1512 lines
52 KiB
Java
1512 lines
52 KiB
Java
/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package me.imid.swipebacklayout.lib;
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import android.content.Context;
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import android.support.v4.view.MotionEventCompat;
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import android.support.v4.view.VelocityTrackerCompat;
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import android.support.v4.view.ViewCompat;
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import android.support.v4.widget.ScrollerCompat;
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import android.view.MotionEvent;
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import android.view.VelocityTracker;
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import android.view.View;
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import android.view.ViewConfiguration;
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import android.view.ViewGroup;
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import android.view.animation.Interpolator;
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import java.util.Arrays;
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/**
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* ViewDragHelper is a utility class for writing custom ViewGroups. It offers a
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* number of useful operations and state tracking for allowing a user to drag
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* and reposition views within their parent ViewGroup.
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*/
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public class ViewDragHelper {
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/**
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* A null/invalid pointer ID.
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*/
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public static final int INVALID_POINTER = -1;
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/**
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* A view is not currently being dragged or animating as a result of a
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* fling/snap.
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*/
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public static final int STATE_IDLE = 0;
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/**
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* A view is currently being dragged. The position is currently changing as
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* a result of user input or simulated user input.
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*/
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public static final int STATE_DRAGGING = 1;
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/**
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* A view is currently settling into place as a result of a fling or
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* predefined non-interactive motion.
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*/
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public static final int STATE_SETTLING = 2;
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/**
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* Edge flag indicating that the left edge should be affected.
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*/
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public static final int EDGE_LEFT = 1 << 0;
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/**
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* Edge flag indicating that the right edge should be affected.
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*/
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public static final int EDGE_RIGHT = 1 << 1;
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/**
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* Edge flag indicating that the top edge should be affected.
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*/
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public static final int EDGE_TOP = 1 << 2;
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/**
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* Edge flag indicating that the bottom edge should be affected.
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*/
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public static final int EDGE_BOTTOM = 1 << 3;
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/**
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* Edge flag set indicating all edges should be affected.
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*/
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public static final int EDGE_ALL = EDGE_LEFT | EDGE_TOP | EDGE_RIGHT | EDGE_BOTTOM;
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/**
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* Indicates that a check should occur along the horizontal axis
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*/
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public static final int DIRECTION_HORIZONTAL = 1 << 0;
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/**
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* Indicates that a check should occur along the vertical axis
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*/
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public static final int DIRECTION_VERTICAL = 1 << 1;
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/**
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* Indicates that a check should occur along all axes
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*/
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public static final int DIRECTION_ALL = DIRECTION_HORIZONTAL | DIRECTION_VERTICAL;
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public static final int EDGE_SIZE = 20; // dp
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private static final int BASE_SETTLE_DURATION = 256; // ms
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private static final int MAX_SETTLE_DURATION = 600; // ms
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// Current drag state; idle, dragging or settling
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private int mDragState;
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// Distance to travel before a drag may begin
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private int mTouchSlop;
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// Last known position/pointer tracking
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private int mActivePointerId = INVALID_POINTER;
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private float[] mInitialMotionX;
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private float[] mInitialMotionY;
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private float[] mLastMotionX;
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private float[] mLastMotionY;
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private int[] mInitialEdgesTouched;
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private int[] mEdgeDragsInProgress;
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private int[] mEdgeDragsLocked;
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private int mPointersDown;
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private VelocityTracker mVelocityTracker;
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private final float mMaxVelocity;
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private float mMinVelocity;
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private int mEdgeSize;
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private int mTrackingEdges;
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private final ScrollerCompat mScroller;
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private final Callback mCallback;
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private View mCapturedView;
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private boolean mReleaseInProgress;
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private final ViewGroup mParentView;
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/**
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* Interpolator defining the animation curve for mScroller
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*/
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private static final Interpolator sInterpolator = new Interpolator() {
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@Override
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public float getInterpolation(float t) {
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t -= 1.0f;
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return t * t * t * t * t + 1.0f;
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}
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};
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private final Runnable mSetIdleRunnable = new Runnable() {
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@Override
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public void run() {
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setDragState(STATE_IDLE);
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}
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};
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/**
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* Apps should use ViewDragHelper.create() to get a new instance. This will
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* allow VDH to use internal compatibility implementations for different
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* platform versions.
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*
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* @param context Context to initialize config-dependent params from
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* @param forParent Parent view to monitor
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*/
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private ViewDragHelper(final Context context, final ViewGroup forParent, final Callback cb) {
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if (forParent == null) throw new IllegalArgumentException("Parent view may not be null");
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if (cb == null) throw new IllegalArgumentException("Callback may not be null");
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mParentView = forParent;
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mCallback = cb;
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final ViewConfiguration vc = ViewConfiguration.get(context);
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final float density = context.getResources().getDisplayMetrics().density;
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mEdgeSize = (int) (EDGE_SIZE * density + 0.5f);
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mTouchSlop = vc.getScaledTouchSlop();
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mMaxVelocity = vc.getScaledMaximumFlingVelocity();
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mMinVelocity = vc.getScaledMinimumFlingVelocity();
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mScroller = ScrollerCompat.create(context, sInterpolator);
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}
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/**
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* {@link #cancel()}, but also abort all motion in progress and snap to the
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* end of any animation.
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*/
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public void abort() {
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cancel();
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if (mDragState == STATE_SETTLING) {
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final int oldX = mScroller.getCurrX();
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final int oldY = mScroller.getCurrY();
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mScroller.abortAnimation();
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final int newX = mScroller.getCurrX();
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final int newY = mScroller.getCurrY();
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mCallback.onViewPositionChanged(mCapturedView, newX, newY, newX - oldX, newY - oldY);
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}
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setDragState(STATE_IDLE);
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}
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/**
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* The result of a call to this method is equivalent to
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* {@link #processTouchEvent(android.view.MotionEvent)} receiving an
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* ACTION_CANCEL event.
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*/
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public void cancel() {
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mActivePointerId = INVALID_POINTER;
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clearMotionHistory();
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if (mVelocityTracker != null) {
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mVelocityTracker.recycle();
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mVelocityTracker = null;
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}
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}
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/**
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* Capture a specific child view for dragging within the parent. The
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* callback will be notified but
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* {@link me.imid.swipebacklayout.lib.ViewDragHelper.Callback#tryCaptureView(android.view.View, int)}
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* will not be asked permission to capture this view.
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*
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* @param childView Child view to capture
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* @param activePointerId ID of the pointer that is dragging the captured
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* child view
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*/
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public void captureChildView(final View childView, final int activePointerId) {
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if (childView.getParent() != mParentView)
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throw new IllegalArgumentException("captureChildView: parameter must be a descendant "
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+ "of the ViewDragHelper's tracked parent view (" + mParentView + ")");
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mCapturedView = childView;
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mActivePointerId = activePointerId;
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mCallback.onViewCaptured(childView, activePointerId);
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setDragState(STATE_DRAGGING);
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}
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/**
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* Check if any pointer tracked in the current gesture has crossed the
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* required slop threshold.
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* <p>
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* This depends on internal state populated by
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* {@link #shouldInterceptTouchEvent(android.view.MotionEvent)} or
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* {@link #processTouchEvent(android.view.MotionEvent)}. You should only
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* rely on the results of this method after all currently available touch
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* data has been provided to one of these two methods.
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* </p>
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*
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* @param directions Combination of direction flags, see
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* {@link #DIRECTION_HORIZONTAL}, {@link #DIRECTION_VERTICAL},
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* {@link #DIRECTION_ALL}
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* @return true if the slop threshold has been crossed, false otherwise
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*/
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public boolean checkTouchSlop(final int directions) {
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final int count = mInitialMotionX.length;
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for (int i = 0; i < count; i++) {
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if (checkTouchSlop(directions, i)) return true;
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}
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return false;
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}
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/**
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* Check if the specified pointer tracked in the current gesture has crossed
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* the required slop threshold.
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* <p>
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* This depends on internal state populated by
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* {@link #shouldInterceptTouchEvent(android.view.MotionEvent)} or
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* {@link #processTouchEvent(android.view.MotionEvent)}. You should only
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* rely on the results of this method after all currently available touch
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* data has been provided to one of these two methods.
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* </p>
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*
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* @param directions Combination of direction flags, see
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* {@link #DIRECTION_HORIZONTAL}, {@link #DIRECTION_VERTICAL},
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* {@link #DIRECTION_ALL}
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* @param pointerId ID of the pointer to slop check as specified by
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* MotionEvent
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* @return true if the slop threshold has been crossed, false otherwise
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*/
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public boolean checkTouchSlop(final int directions, final int pointerId) {
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if (!isPointerDown(pointerId)) return false;
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final boolean checkHorizontal = (directions & DIRECTION_HORIZONTAL) == DIRECTION_HORIZONTAL;
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final boolean checkVertical = (directions & DIRECTION_VERTICAL) == DIRECTION_VERTICAL;
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final float dx = mLastMotionX[pointerId] - mInitialMotionX[pointerId];
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final float dy = mLastMotionY[pointerId] - mInitialMotionY[pointerId];
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if (checkHorizontal && checkVertical)
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return dx * dx + dy * dy > mTouchSlop * mTouchSlop;
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else if (checkHorizontal)
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return Math.abs(dx) > mTouchSlop;
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else if (checkVertical) return Math.abs(dy) > mTouchSlop;
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return false;
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}
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/**
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* Move the captured settling view by the appropriate amount for the current
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* time. If <code>continueSettling</code> returns true, the caller should
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* call it again on the next frame to continue.
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*
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* @param deferCallbacks true if state callbacks should be deferred via
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* posted message. Set this to true if you are calling this
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* method from {@link android.view.View#computeScroll()} or
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* similar methods invoked as part of layout or drawing.
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* @return true if settle is still in progress
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*/
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public boolean continueSettling(final boolean deferCallbacks) {
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if (mDragState == STATE_SETTLING) {
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boolean keepGoing = mScroller.computeScrollOffset();
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final int x = mScroller.getCurrX();
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final int y = mScroller.getCurrY();
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final int dx = x - mCapturedView.getLeft();
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final int dy = y - mCapturedView.getTop();
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if (dx != 0) {
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mCapturedView.offsetLeftAndRight(dx);
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}
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if (dy != 0) {
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mCapturedView.offsetTopAndBottom(dy);
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}
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if (dx != 0 || dy != 0) {
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mCallback.onViewPositionChanged(mCapturedView, x, y, dx, dy);
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}
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if (keepGoing && x == mScroller.getFinalX() && y == mScroller.getFinalY()) {
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// Close enough. The interpolator/scroller might think we're
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// still moving
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// but the user sure doesn't.
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mScroller.abortAnimation();
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keepGoing = mScroller.isFinished();
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}
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if (!keepGoing) {
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if (deferCallbacks) {
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mParentView.post(mSetIdleRunnable);
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} else {
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setDragState(STATE_IDLE);
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}
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}
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}
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return mDragState == STATE_SETTLING;
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}
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/**
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* Find the topmost child under the given point within the parent view's
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* coordinate system. The child order is determined using
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* {@link me.imid.swipebacklayout.lib.ViewDragHelper.Callback#getOrderedChildIndex(int)}
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* .
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*
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* @param x X position to test in the parent's coordinate system
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* @param y Y position to test in the parent's coordinate system
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* @return The topmost child view under (x, y) or null if none found.
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*/
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public View findTopChildUnder(final int x, final int y) {
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final int childCount = mParentView.getChildCount();
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for (int i = childCount - 1; i >= 0; i--) {
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final View child = mParentView.getChildAt(mCallback.getOrderedChildIndex(i));
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if (x >= child.getLeft() && x < child.getRight() && y >= child.getTop() && y < child.getBottom())
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return child;
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}
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return null;
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}
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/**
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* Settle the captured view based on standard free-moving fling behavior.
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* The caller should invoke {@link #continueSettling(boolean)} on each
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* subsequent frame to continue the motion until it returns false.
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*
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* @param minLeft Minimum X position for the view's left edge
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* @param minTop Minimum Y position for the view's top edge
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* @param maxLeft Maximum X position for the view's left edge
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* @param maxTop Maximum Y position for the view's top edge
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*/
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public void flingCapturedView(final int minLeft, final int minTop, final int maxLeft, final int maxTop) {
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if (!mReleaseInProgress)
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throw new IllegalStateException("Cannot flingCapturedView outside of a call to "
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+ "Callback#onViewReleased");
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mScroller.fling(mCapturedView.getLeft(), mCapturedView.getTop(),
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(int) VelocityTrackerCompat.getXVelocity(mVelocityTracker, mActivePointerId),
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(int) VelocityTrackerCompat.getYVelocity(mVelocityTracker, mActivePointerId), minLeft, maxLeft, minTop,
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maxTop);
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setDragState(STATE_SETTLING);
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}
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/**
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* @return The ID of the pointer currently dragging the captured view, or
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* {@link #INVALID_POINTER}.
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*/
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public int getActivePointerId() {
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return mActivePointerId;
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}
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/**
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* @return The currently captured view, or null if no view has been
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* captured.
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*/
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public View getCapturedView() {
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return mCapturedView;
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}
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/**
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* Return the size of an edge. This is the range in pixels along the edges
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* of this view that will actively detect edge touches or drags if edge
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* tracking is enabled.
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*
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* @return The size of an edge in pixels
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* @see #setEdgeTrackingEnabled(int)
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*/
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public int getEdgeSize() {
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return mEdgeSize;
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}
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/**
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* Return the currently configured minimum velocity. Any flings with a
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* magnitude less than this value in pixels per second. Callback methods
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* accepting a velocity will receive zero as a velocity value if the real
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* detected velocity was below this threshold.
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*
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* @return the minimum velocity that will be detected
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*/
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public float getMinVelocity() {
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return mMinVelocity;
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}
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/**
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* @return The minimum distance in pixels that the user must travel to
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* initiate a drag
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*/
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public int getTouchSlop() {
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return mTouchSlop;
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}
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/**
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* Retrieve the current drag state of this helper. This will return one of
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* {@link #STATE_IDLE}, {@link #STATE_DRAGGING} or {@link #STATE_SETTLING}.
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*
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* @return The current drag state
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*/
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public int getViewDragState() {
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return mDragState;
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}
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/**
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* Determine if the currently captured view is under the given point in the
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* parent view's coordinate system. If there is no captured view this method
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* will return false.
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*
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* @param x X position to test in the parent's coordinate system
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* @param y Y position to test in the parent's coordinate system
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* @return true if the captured view is under the given point, false
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* otherwise
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*/
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public boolean isCapturedViewUnder(final int x, final int y) {
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return isViewUnder(mCapturedView, x, y);
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}
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/**
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* Check if any of the edges specified were initially touched in the
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* currently active gesture. If there is no currently active gesture this
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* method will return false.
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*
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* @param edges Edges to check for an initial edge touch. See
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* {@link #EDGE_LEFT}, {@link #EDGE_TOP}, {@link #EDGE_RIGHT},
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* {@link #EDGE_BOTTOM} and {@link #EDGE_ALL}
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* @return true if any of the edges specified were initially touched in the
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* current gesture
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*/
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public boolean isEdgeTouched(final int edges) {
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final int count = mInitialEdgesTouched.length;
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for (int i = 0; i < count; i++) {
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if (isEdgeTouched(edges, i)) return true;
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}
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return false;
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}
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/**
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* Check if any of the edges specified were initially touched by the pointer
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* with the specified ID. If there is no currently active gesture or if
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* there is no pointer with the given ID currently down this method will
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* return false.
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*
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* @param edges Edges to check for an initial edge touch. See
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* {@link #EDGE_LEFT}, {@link #EDGE_TOP}, {@link #EDGE_RIGHT},
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* {@link #EDGE_BOTTOM} and {@link #EDGE_ALL}
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* @return true if any of the edges specified were initially touched in the
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* current gesture
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*/
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public boolean isEdgeTouched(final int edges, final int pointerId) {
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return isPointerDown(pointerId) && (mInitialEdgesTouched[pointerId] & edges) != 0;
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}
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/**
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* Check if the given pointer ID represents a pointer that is currently down
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* (to the best of the ViewDragHelper's knowledge).
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* <p>
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* The state used to report this information is populated by the methods
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* {@link #shouldInterceptTouchEvent(android.view.MotionEvent)} or
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* {@link #processTouchEvent(android.view.MotionEvent)}. If one of these
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* methods has not been called for all relevant MotionEvents to track, the
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* information reported by this method may be stale or incorrect.
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* </p>
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*
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* @param pointerId pointer ID to check; corresponds to IDs provided by
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* MotionEvent
|
|
* @return true if the pointer with the given ID is still down
|
|
*/
|
|
public boolean isPointerDown(final int pointerId) {
|
|
return (mPointersDown & 1 << pointerId) != 0;
|
|
}
|
|
|
|
/**
|
|
* Determine if the supplied view is under the given point in the parent
|
|
* view's coordinate system.
|
|
*
|
|
* @param view Child view of the parent to hit test
|
|
* @param x X position to test in the parent's coordinate system
|
|
* @param y Y position to test in the parent's coordinate system
|
|
* @return true if the supplied view is under the given point, false
|
|
* otherwise
|
|
*/
|
|
public boolean isViewUnder(final View view, final int x, final int y) {
|
|
if (view == null) return false;
|
|
return x >= view.getLeft() && x < view.getRight() && y >= view.getTop() && y < view.getBottom();
|
|
}
|
|
|
|
/**
|
|
* Process a touch event received by the parent view. This method will
|
|
* dispatch callback events as needed before returning. The parent view's
|
|
* onTouchEvent implementation should call this.
|
|
*
|
|
* @param ev The touch event received by the parent view
|
|
*/
|
|
public void processTouchEvent(final MotionEvent ev) {
|
|
final int action = MotionEventCompat.getActionMasked(ev);
|
|
final int actionIndex = MotionEventCompat.getActionIndex(ev);
|
|
|
|
if (action == MotionEvent.ACTION_DOWN) {
|
|
// Reset things for a new event stream, just in case we didn't get
|
|
// the whole previous stream.
|
|
cancel();
|
|
}
|
|
|
|
if (mVelocityTracker == null) {
|
|
mVelocityTracker = VelocityTracker.obtain();
|
|
}
|
|
mVelocityTracker.addMovement(ev);
|
|
|
|
switch (action) {
|
|
case MotionEvent.ACTION_DOWN: {
|
|
final float x = ev.getX();
|
|
final float y = ev.getY();
|
|
final int pointerId = MotionEventCompat.getPointerId(ev, 0);
|
|
final View toCapture = findTopChildUnder((int) x, (int) y);
|
|
|
|
saveInitialMotion(x, y, pointerId);
|
|
|
|
// Since the parent is already directly processing this touch
|
|
// event,
|
|
// there is no reason to delay for a slop before dragging.
|
|
// Start immediately if possible.
|
|
tryCaptureViewForDrag(toCapture, pointerId);
|
|
|
|
final int edgesTouched = mInitialEdgesTouched[pointerId];
|
|
if ((edgesTouched & mTrackingEdges) != 0) {
|
|
mCallback.onEdgeTouched(edgesTouched & mTrackingEdges, pointerId);
|
|
}
|
|
break;
|
|
}
|
|
|
|
case MotionEventCompat.ACTION_POINTER_DOWN: {
|
|
final int pointerId = MotionEventCompat.getPointerId(ev, actionIndex);
|
|
final float x = MotionEventCompat.getX(ev, actionIndex);
|
|
final float y = MotionEventCompat.getY(ev, actionIndex);
|
|
|
|
saveInitialMotion(x, y, pointerId);
|
|
|
|
// A ViewDragHelper can only manipulate one view at a time.
|
|
if (mDragState == STATE_IDLE) {
|
|
// If we're idle we can do anything! Treat it like a normal
|
|
// down event.
|
|
|
|
final View toCapture = findTopChildUnder((int) x, (int) y);
|
|
tryCaptureViewForDrag(toCapture, pointerId);
|
|
|
|
final int edgesTouched = mInitialEdgesTouched[pointerId];
|
|
if ((edgesTouched & mTrackingEdges) != 0) {
|
|
mCallback.onEdgeTouched(edgesTouched & mTrackingEdges, pointerId);
|
|
}
|
|
} else if (isCapturedViewUnder((int) x, (int) y)) {
|
|
// We're still tracking a captured view. If the same view is
|
|
// under this
|
|
// point, we'll swap to controlling it with this pointer
|
|
// instead.
|
|
// (This will still work if we're "catching" a settling
|
|
// view.)
|
|
|
|
tryCaptureViewForDrag(mCapturedView, pointerId);
|
|
}
|
|
break;
|
|
}
|
|
|
|
case MotionEvent.ACTION_MOVE: {
|
|
if (mDragState == STATE_DRAGGING) {
|
|
final int index = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
|
|
final float x = MotionEventCompat.getX(ev, index);
|
|
final float y = MotionEventCompat.getY(ev, index);
|
|
final int idx = (int) (x - mLastMotionX[mActivePointerId]);
|
|
final int idy = (int) (y - mLastMotionY[mActivePointerId]);
|
|
|
|
dragTo(mCapturedView.getLeft() + idx, mCapturedView.getTop() + idy, idx, idy);
|
|
|
|
saveLastMotion(ev);
|
|
} else {
|
|
// Check to see if any pointer is now over a draggable view.
|
|
final int pointerCount = MotionEventCompat.getPointerCount(ev);
|
|
for (int i = 0; i < pointerCount; i++) {
|
|
final int pointerId = MotionEventCompat.getPointerId(ev, i);
|
|
final float x = MotionEventCompat.getX(ev, i);
|
|
final float y = MotionEventCompat.getY(ev, i);
|
|
final float dx = x - mInitialMotionX[pointerId];
|
|
final float dy = y - mInitialMotionY[pointerId];
|
|
|
|
reportNewEdgeDrags(dx, dy, pointerId);
|
|
if (mDragState == STATE_DRAGGING) {
|
|
// Callback might have started an edge drag.
|
|
break;
|
|
}
|
|
|
|
final View toCapture = findTopChildUnder((int) x, (int) y);
|
|
if (checkTouchSlop(toCapture, dx, dy) && tryCaptureViewForDrag(toCapture, pointerId)) {
|
|
break;
|
|
}
|
|
}
|
|
saveLastMotion(ev);
|
|
}
|
|
break;
|
|
}
|
|
|
|
case MotionEventCompat.ACTION_POINTER_UP: {
|
|
final int pointerId = MotionEventCompat.getPointerId(ev, actionIndex);
|
|
if (mDragState == STATE_DRAGGING && pointerId == mActivePointerId) {
|
|
// Try to find another pointer that's still holding on to
|
|
// the captured view.
|
|
int newActivePointer = INVALID_POINTER;
|
|
final int pointerCount = MotionEventCompat.getPointerCount(ev);
|
|
for (int i = 0; i < pointerCount; i++) {
|
|
final int id = MotionEventCompat.getPointerId(ev, i);
|
|
if (id == mActivePointerId) {
|
|
// This one's going away, skip.
|
|
continue;
|
|
}
|
|
|
|
final float x = MotionEventCompat.getX(ev, i);
|
|
final float y = MotionEventCompat.getY(ev, i);
|
|
if (findTopChildUnder((int) x, (int) y) == mCapturedView
|
|
&& tryCaptureViewForDrag(mCapturedView, id)) {
|
|
newActivePointer = mActivePointerId;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (newActivePointer == INVALID_POINTER) {
|
|
// We didn't find another pointer still touching the
|
|
// view, release it.
|
|
releaseViewForPointerUp();
|
|
}
|
|
}
|
|
clearMotionHistory(pointerId);
|
|
break;
|
|
}
|
|
|
|
case MotionEvent.ACTION_UP: {
|
|
if (mDragState == STATE_DRAGGING) {
|
|
releaseViewForPointerUp();
|
|
}
|
|
cancel();
|
|
break;
|
|
}
|
|
|
|
case MotionEvent.ACTION_CANCEL: {
|
|
if (mDragState == STATE_DRAGGING) {
|
|
dispatchViewReleased(0, 0);
|
|
}
|
|
cancel();
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Set the size of an edge. This is the range in pixels along the edges of
|
|
* this view that will actively detect edge touches or drags if edge
|
|
* tracking is enabled.
|
|
*
|
|
* @param size The size of an edge in pixels
|
|
*/
|
|
public void setEdgeSize(final int size) {
|
|
mEdgeSize = size;
|
|
}
|
|
|
|
/**
|
|
* Enable edge tracking for the selected edges of the parent view. The
|
|
* callback's
|
|
* {@link me.imid.swipebacklayout.lib.ViewDragHelper.Callback#onEdgeTouched(int, int)}
|
|
* and
|
|
* {@link me.imid.swipebacklayout.lib.ViewDragHelper.Callback#onEdgeDragStarted(int, int)}
|
|
* methods will only be invoked for edges for which edge tracking has been
|
|
* enabled.
|
|
*
|
|
* @param edgeFlags Combination of edge flags describing the edges to watch
|
|
* @see #EDGE_LEFT
|
|
* @see #EDGE_TOP
|
|
* @see #EDGE_RIGHT
|
|
* @see #EDGE_BOTTOM
|
|
*/
|
|
public void setEdgeTrackingEnabled(final int edgeFlags) {
|
|
mTrackingEdges = edgeFlags;
|
|
}
|
|
|
|
/**
|
|
* Set the minimum velocity that will be detected as having a magnitude
|
|
* greater than zero in pixels per second. Callback methods accepting a
|
|
* velocity will be clamped appropriately.
|
|
*
|
|
* @param minVel Minimum velocity to detect
|
|
*/
|
|
public void setMinVelocity(final float minVel) {
|
|
mMinVelocity = minVel;
|
|
}
|
|
|
|
/**
|
|
* Settle the captured view at the given (left, top) position. The
|
|
* appropriate velocity from prior motion will be taken into account. If
|
|
* this method returns true, the caller should invoke
|
|
* {@link #continueSettling(boolean)} on each subsequent frame to continue
|
|
* the motion until it returns false. If this method returns false there is
|
|
* no further work to do to complete the movement.
|
|
*
|
|
* @param finalLeft Settled left edge position for the captured view
|
|
* @param finalTop Settled top edge position for the captured view
|
|
* @return true if animation should continue through
|
|
* {@link #continueSettling(boolean)} calls
|
|
*/
|
|
public boolean settleCapturedViewAt(final int finalLeft, final int finalTop) {
|
|
if (!mReleaseInProgress)
|
|
throw new IllegalStateException("Cannot settleCapturedViewAt outside of a call to "
|
|
+ "Callback#onViewReleased");
|
|
|
|
return forceSettleCapturedViewAt(finalLeft, finalTop,
|
|
(int) VelocityTrackerCompat.getXVelocity(mVelocityTracker, mActivePointerId),
|
|
(int) VelocityTrackerCompat.getYVelocity(mVelocityTracker, mActivePointerId));
|
|
}
|
|
|
|
/**
|
|
* Check if this event as provided to the parent view's
|
|
* onInterceptTouchEvent should cause the parent to intercept the touch
|
|
* event stream.
|
|
*
|
|
* @param ev MotionEvent provided to onInterceptTouchEvent
|
|
* @return true if the parent view should return true from
|
|
* onInterceptTouchEvent
|
|
*/
|
|
public boolean shouldInterceptTouchEvent(final MotionEvent ev) {
|
|
final int action = MotionEventCompat.getActionMasked(ev);
|
|
final int actionIndex = MotionEventCompat.getActionIndex(ev);
|
|
|
|
if (action == MotionEvent.ACTION_DOWN) {
|
|
// Reset things for a new event stream, just in case we didn't get
|
|
// the whole previous stream.
|
|
cancel();
|
|
}
|
|
|
|
if (mVelocityTracker == null) {
|
|
mVelocityTracker = VelocityTracker.obtain();
|
|
}
|
|
mVelocityTracker.addMovement(ev);
|
|
|
|
switch (action) {
|
|
case MotionEvent.ACTION_DOWN: {
|
|
final float x = ev.getX();
|
|
final float y = ev.getY();
|
|
final int pointerId = MotionEventCompat.getPointerId(ev, 0);
|
|
saveInitialMotion(x, y, pointerId);
|
|
|
|
final View toCapture = findTopChildUnder((int) x, (int) y);
|
|
|
|
// Catch a settling view if possible.
|
|
if (toCapture == mCapturedView && mDragState == STATE_SETTLING) {
|
|
tryCaptureViewForDrag(toCapture, pointerId);
|
|
}
|
|
|
|
final int edgesTouched = mInitialEdgesTouched[pointerId];
|
|
if ((edgesTouched & mTrackingEdges) != 0) {
|
|
mCallback.onEdgeTouched(edgesTouched & mTrackingEdges, pointerId);
|
|
}
|
|
break;
|
|
}
|
|
|
|
case MotionEventCompat.ACTION_POINTER_DOWN: {
|
|
final int pointerId = MotionEventCompat.getPointerId(ev, actionIndex);
|
|
final float x = MotionEventCompat.getX(ev, actionIndex);
|
|
final float y = MotionEventCompat.getY(ev, actionIndex);
|
|
|
|
saveInitialMotion(x, y, pointerId);
|
|
|
|
// A ViewDragHelper can only manipulate one view at a time.
|
|
if (mDragState == STATE_IDLE) {
|
|
final int edgesTouched = mInitialEdgesTouched[pointerId];
|
|
if ((edgesTouched & mTrackingEdges) != 0) {
|
|
mCallback.onEdgeTouched(edgesTouched & mTrackingEdges, pointerId);
|
|
}
|
|
} else if (mDragState == STATE_SETTLING) {
|
|
// Catch a settling view if possible.
|
|
final View toCapture = findTopChildUnder((int) x, (int) y);
|
|
if (toCapture == mCapturedView) {
|
|
tryCaptureViewForDrag(toCapture, pointerId);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
case MotionEvent.ACTION_MOVE: {
|
|
// First to cross a touch slop over a draggable view wins. Also
|
|
// report edge drags.
|
|
final int pointerCount = MotionEventCompat.getPointerCount(ev);
|
|
for (int i = 0; i < pointerCount; i++) {
|
|
final int pointerId = MotionEventCompat.getPointerId(ev, i);
|
|
final float x = MotionEventCompat.getX(ev, i);
|
|
final float y = MotionEventCompat.getY(ev, i);
|
|
final float dx = x - mInitialMotionX[pointerId];
|
|
final float dy = y - mInitialMotionY[pointerId];
|
|
|
|
reportNewEdgeDrags(dx, dy, pointerId);
|
|
if (mDragState == STATE_DRAGGING) {
|
|
// Callback might have started an edge drag
|
|
break;
|
|
}
|
|
|
|
final View toCapture = findTopChildUnder((int) x, (int) y);
|
|
if (toCapture != null && checkTouchSlop(toCapture, dx, dy)
|
|
&& tryCaptureViewForDrag(toCapture, pointerId)) {
|
|
break;
|
|
}
|
|
}
|
|
saveLastMotion(ev);
|
|
break;
|
|
}
|
|
|
|
case MotionEventCompat.ACTION_POINTER_UP: {
|
|
final int pointerId = MotionEventCompat.getPointerId(ev, actionIndex);
|
|
clearMotionHistory(pointerId);
|
|
break;
|
|
}
|
|
|
|
case MotionEvent.ACTION_UP:
|
|
case MotionEvent.ACTION_CANCEL: {
|
|
cancel();
|
|
break;
|
|
}
|
|
}
|
|
|
|
return mDragState == STATE_DRAGGING;
|
|
}
|
|
|
|
/**
|
|
* Animate the view <code>child</code> to the given (left, top) position. If
|
|
* this method returns true, the caller should invoke
|
|
* {@link #continueSettling(boolean)} on each subsequent frame to continue
|
|
* the motion until it returns false. If this method returns false there is
|
|
* no further work to do to complete the movement.
|
|
* <p>
|
|
* This operation does not count as a capture event, though
|
|
* {@link #getCapturedView()} will still report the sliding view while the
|
|
* slide is in progress.
|
|
* </p>
|
|
*
|
|
* @param child Child view to capture and animate
|
|
* @param finalLeft Final left position of child
|
|
* @param finalTop Final top position of child
|
|
* @return true if animation should continue through
|
|
* {@link #continueSettling(boolean)} calls
|
|
*/
|
|
public boolean smoothSlideViewTo(final View child, final int finalLeft, final int finalTop) {
|
|
mCapturedView = child;
|
|
mActivePointerId = INVALID_POINTER;
|
|
|
|
return forceSettleCapturedViewAt(finalLeft, finalTop, 0, 0);
|
|
}
|
|
|
|
/**
|
|
* Tests scrollability within child views of v given a delta of dx.
|
|
*
|
|
* @param v View to test for horizontal scrollability
|
|
* @param checkV Whether the view v passed should itself be checked for
|
|
* scrollability (true), or just its children (false).
|
|
* @param dx Delta scrolled in pixels along the X axis
|
|
* @param dy Delta scrolled in pixels along the Y axis
|
|
* @param x X coordinate of the active touch point
|
|
* @param y Y coordinate of the active touch point
|
|
* @return true if child views of v can be scrolled by delta of dx.
|
|
*/
|
|
protected boolean canScroll(final View v, final boolean checkV, final int dx, final int dy, final int x, final int y) {
|
|
if (v instanceof ViewGroup) {
|
|
final ViewGroup group = (ViewGroup) v;
|
|
final int scrollX = v.getScrollX();
|
|
final int scrollY = v.getScrollY();
|
|
final int count = group.getChildCount();
|
|
// Count backwards - let topmost views consume scroll distance
|
|
// first.
|
|
for (int i = count - 1; i >= 0; i--) {
|
|
// TODO: Add versioned support here for transformed views.
|
|
// This will not work for transformed views in Honeycomb+
|
|
final View child = group.getChildAt(i);
|
|
if (x + scrollX >= child.getLeft() && x + scrollX < child.getRight() && y + scrollY >= child.getTop()
|
|
&& y + scrollY < child.getBottom()
|
|
&& canScroll(child, true, dx, dy, x + scrollX - child.getLeft(), y + scrollY - child.getTop()))
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return checkV && (ViewCompat.canScrollHorizontally(v, -dx) || ViewCompat.canScrollVertically(v, -dy));
|
|
}
|
|
|
|
private boolean checkNewEdgeDrag(final float delta, final float odelta, final int pointerId, final int edge) {
|
|
final float absDelta = Math.abs(delta);
|
|
final float absODelta = Math.abs(odelta);
|
|
|
|
if ((mInitialEdgesTouched[pointerId] & edge) != edge || (mTrackingEdges & edge) == 0
|
|
|| (mEdgeDragsLocked[pointerId] & edge) == edge || (mEdgeDragsInProgress[pointerId] & edge) == edge
|
|
|| absDelta <= mTouchSlop && absODelta <= mTouchSlop) return false;
|
|
if (absDelta < absODelta * 0.5f && mCallback.onEdgeLock(edge)) {
|
|
mEdgeDragsLocked[pointerId] |= edge;
|
|
return false;
|
|
}
|
|
return (mEdgeDragsInProgress[pointerId] & edge) == 0 && absDelta > mTouchSlop;
|
|
}
|
|
|
|
/**
|
|
* Check if we've crossed a reasonable touch slop for the given child view.
|
|
* If the child cannot be dragged along the horizontal or vertical axis,
|
|
* motion along that axis will not count toward the slop check.
|
|
*
|
|
* @param child Child to check
|
|
* @param dx Motion since initial position along X axis
|
|
* @param dy Motion since initial position along Y axis
|
|
* @return true if the touch slop has been crossed
|
|
*/
|
|
private boolean checkTouchSlop(final View child, final float dx, final float dy) {
|
|
if (child == null) return false;
|
|
final boolean checkHorizontal = mCallback.getViewHorizontalDragRange(child) > 0;
|
|
final boolean checkVertical = mCallback.getViewVerticalDragRange(child) > 0;
|
|
|
|
if (checkHorizontal && checkVertical)
|
|
return dx * dx + dy * dy > mTouchSlop * mTouchSlop;
|
|
else if (checkHorizontal)
|
|
return Math.abs(dx) > mTouchSlop;
|
|
else if (checkVertical) return Math.abs(dy) > mTouchSlop;
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Clamp the magnitude of value for absMin and absMax. If the value is below
|
|
* the minimum, it will be clamped to zero. If the value is above the
|
|
* maximum, it will be clamped to the maximum.
|
|
*
|
|
* @param value Value to clamp
|
|
* @param absMin Absolute value of the minimum significant value to return
|
|
* @param absMax Absolute value of the maximum value to return
|
|
* @return The clamped value with the same sign as <code>value</code>
|
|
*/
|
|
private float clampMag(final float value, final float absMin, final float absMax) {
|
|
final float absValue = Math.abs(value);
|
|
if (absValue < absMin) return 0;
|
|
if (absValue > absMax) return value > 0 ? absMax : -absMax;
|
|
return value;
|
|
}
|
|
|
|
/**
|
|
* Clamp the magnitude of value for absMin and absMax. If the value is below
|
|
* the minimum, it will be clamped to zero. If the value is above the
|
|
* maximum, it will be clamped to the maximum.
|
|
*
|
|
* @param value Value to clamp
|
|
* @param absMin Absolute value of the minimum significant value to return
|
|
* @param absMax Absolute value of the maximum value to return
|
|
* @return The clamped value with the same sign as <code>value</code>
|
|
*/
|
|
private int clampMag(final int value, final int absMin, final int absMax) {
|
|
final int absValue = Math.abs(value);
|
|
if (absValue < absMin) return 0;
|
|
if (absValue > absMax) return value > 0 ? absMax : -absMax;
|
|
return value;
|
|
}
|
|
|
|
private void clearMotionHistory() {
|
|
if (mInitialMotionX == null) return;
|
|
Arrays.fill(mInitialMotionX, 0);
|
|
Arrays.fill(mInitialMotionY, 0);
|
|
Arrays.fill(mLastMotionX, 0);
|
|
Arrays.fill(mLastMotionY, 0);
|
|
Arrays.fill(mInitialEdgesTouched, 0);
|
|
Arrays.fill(mEdgeDragsInProgress, 0);
|
|
Arrays.fill(mEdgeDragsLocked, 0);
|
|
mPointersDown = 0;
|
|
}
|
|
|
|
private void clearMotionHistory(final int pointerId) {
|
|
if (mInitialMotionX == null) return;
|
|
mInitialMotionX[pointerId] = 0;
|
|
mInitialMotionY[pointerId] = 0;
|
|
mLastMotionX[pointerId] = 0;
|
|
mLastMotionY[pointerId] = 0;
|
|
mInitialEdgesTouched[pointerId] = 0;
|
|
mEdgeDragsInProgress[pointerId] = 0;
|
|
mEdgeDragsLocked[pointerId] = 0;
|
|
mPointersDown &= ~(1 << pointerId);
|
|
}
|
|
|
|
private int computeAxisDuration(final int delta, int velocity, final int motionRange) {
|
|
if (delta == 0) return 0;
|
|
|
|
final int width = mParentView.getWidth();
|
|
final int halfWidth = width / 2;
|
|
final float distanceRatio = Math.min(1f, (float) Math.abs(delta) / width);
|
|
final float distance = halfWidth + halfWidth * distanceInfluenceForSnapDuration(distanceRatio);
|
|
|
|
int duration;
|
|
velocity = Math.abs(velocity);
|
|
if (velocity > 0) {
|
|
duration = 4 * Math.round(1000 * Math.abs(distance / velocity));
|
|
} else {
|
|
final float range = (float) Math.abs(delta) / motionRange;
|
|
duration = (int) ((range + 1) * BASE_SETTLE_DURATION);
|
|
}
|
|
return Math.min(duration, MAX_SETTLE_DURATION);
|
|
}
|
|
|
|
private int computeSettleDuration(final View child, final int dx, final int dy, int xvel, int yvel) {
|
|
xvel = clampMag(xvel, (int) mMinVelocity, (int) mMaxVelocity);
|
|
yvel = clampMag(yvel, (int) mMinVelocity, (int) mMaxVelocity);
|
|
final int absDx = Math.abs(dx);
|
|
final int absDy = Math.abs(dy);
|
|
final int absXVel = Math.abs(xvel);
|
|
final int absYVel = Math.abs(yvel);
|
|
final int addedVel = absXVel + absYVel;
|
|
final int addedDistance = absDx + absDy;
|
|
|
|
final float xweight = xvel != 0 ? (float) absXVel / addedVel : (float) absDx / addedDistance;
|
|
final float yweight = yvel != 0 ? (float) absYVel / addedVel : (float) absDy / addedDistance;
|
|
|
|
final int xduration = computeAxisDuration(dx, xvel, mCallback.getViewHorizontalDragRange(child));
|
|
final int yduration = computeAxisDuration(dy, yvel, mCallback.getViewVerticalDragRange(child));
|
|
|
|
return (int) (xduration * xweight + yduration * yweight);
|
|
}
|
|
|
|
/**
|
|
* Like all callback events this must happen on the UI thread, but release
|
|
* involves some extra semantics. During a release (mReleaseInProgress) is
|
|
* the only time it is valid to call {@link #settleCapturedViewAt(int, int)}
|
|
* or {@link #flingCapturedView(int, int, int, int)}.
|
|
*/
|
|
private void dispatchViewReleased(final float xvel, final float yvel) {
|
|
mReleaseInProgress = true;
|
|
mCallback.onViewReleased(mCapturedView, xvel, yvel);
|
|
mReleaseInProgress = false;
|
|
|
|
if (mDragState == STATE_DRAGGING) {
|
|
// onViewReleased didn't call a method that would have changed this.
|
|
// Go idle.
|
|
setDragState(STATE_IDLE);
|
|
}
|
|
}
|
|
|
|
private float distanceInfluenceForSnapDuration(float f) {
|
|
f -= 0.5f; // center the values about 0.
|
|
f *= 0.3f * Math.PI / 2.0f;
|
|
return (float) Math.sin(f);
|
|
}
|
|
|
|
private void dragTo(final int left, final int top, final int dx, final int dy) {
|
|
int clampedX = left;
|
|
int clampedY = top;
|
|
final int oldLeft = mCapturedView.getLeft();
|
|
final int oldTop = mCapturedView.getTop();
|
|
if (dx != 0) {
|
|
clampedX = mCallback.clampViewPositionHorizontal(mCapturedView, left, dx);
|
|
mCapturedView.offsetLeftAndRight(clampedX - oldLeft);
|
|
}
|
|
if (dy != 0) {
|
|
clampedY = mCallback.clampViewPositionVertical(mCapturedView, top, dy);
|
|
mCapturedView.offsetTopAndBottom(clampedY - oldTop);
|
|
}
|
|
|
|
if (dx != 0 || dy != 0) {
|
|
final int clampedDx = clampedX - oldLeft;
|
|
final int clampedDy = clampedY - oldTop;
|
|
mCallback.onViewPositionChanged(mCapturedView, clampedX, clampedY, clampedDx, clampedDy);
|
|
}
|
|
}
|
|
|
|
private void ensureMotionHistorySizeForId(final int pointerId) {
|
|
if (mInitialMotionX == null || mInitialMotionX.length <= pointerId) {
|
|
final float[] imx = new float[pointerId + 1];
|
|
final float[] imy = new float[pointerId + 1];
|
|
final float[] lmx = new float[pointerId + 1];
|
|
final float[] lmy = new float[pointerId + 1];
|
|
final int[] iit = new int[pointerId + 1];
|
|
final int[] edip = new int[pointerId + 1];
|
|
final int[] edl = new int[pointerId + 1];
|
|
|
|
if (mInitialMotionX != null) {
|
|
System.arraycopy(mInitialMotionX, 0, imx, 0, mInitialMotionX.length);
|
|
System.arraycopy(mInitialMotionY, 0, imy, 0, mInitialMotionY.length);
|
|
System.arraycopy(mLastMotionX, 0, lmx, 0, mLastMotionX.length);
|
|
System.arraycopy(mLastMotionY, 0, lmy, 0, mLastMotionY.length);
|
|
System.arraycopy(mInitialEdgesTouched, 0, iit, 0, mInitialEdgesTouched.length);
|
|
System.arraycopy(mEdgeDragsInProgress, 0, edip, 0, mEdgeDragsInProgress.length);
|
|
System.arraycopy(mEdgeDragsLocked, 0, edl, 0, mEdgeDragsLocked.length);
|
|
}
|
|
|
|
mInitialMotionX = imx;
|
|
mInitialMotionY = imy;
|
|
mLastMotionX = lmx;
|
|
mLastMotionY = lmy;
|
|
mInitialEdgesTouched = iit;
|
|
mEdgeDragsInProgress = edip;
|
|
mEdgeDragsLocked = edl;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Settle the captured view at the given (left, top) position.
|
|
*
|
|
* @param finalLeft Target left position for the captured view
|
|
* @param finalTop Target top position for the captured view
|
|
* @param xvel Horizontal velocity
|
|
* @param yvel Vertical velocity
|
|
* @return true if animation should continue through
|
|
* {@link #continueSettling(boolean)} calls
|
|
*/
|
|
private boolean forceSettleCapturedViewAt(final int finalLeft, final int finalTop, final int xvel, final int yvel) {
|
|
final int startLeft = mCapturedView.getLeft();
|
|
final int startTop = mCapturedView.getTop();
|
|
final int dx = finalLeft - startLeft;
|
|
final int dy = finalTop - startTop;
|
|
|
|
if (dx == 0 && dy == 0) {
|
|
// Nothing to do. Send callbacks, be done.
|
|
mScroller.abortAnimation();
|
|
setDragState(STATE_IDLE);
|
|
return false;
|
|
}
|
|
|
|
final int duration = computeSettleDuration(mCapturedView, dx, dy, xvel, yvel);
|
|
mScroller.startScroll(startLeft, startTop, dx, dy, duration);
|
|
|
|
setDragState(STATE_SETTLING);
|
|
return true;
|
|
}
|
|
|
|
private int getEdgesTouched(final int x, final int y) {
|
|
int result = 0;
|
|
|
|
if (x < mParentView.getLeft() + mEdgeSize) {
|
|
result |= EDGE_LEFT;
|
|
}
|
|
if (y < mParentView.getTop() + mEdgeSize) {
|
|
result |= EDGE_TOP;
|
|
}
|
|
if (x > mParentView.getRight() - mEdgeSize) {
|
|
result |= EDGE_RIGHT;
|
|
}
|
|
if (y > mParentView.getBottom() - mEdgeSize) {
|
|
result |= EDGE_BOTTOM;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
private void releaseViewForPointerUp() {
|
|
mVelocityTracker.computeCurrentVelocity(1000, mMaxVelocity);
|
|
final float xvel = clampMag(VelocityTrackerCompat.getXVelocity(mVelocityTracker, mActivePointerId),
|
|
mMinVelocity, mMaxVelocity);
|
|
final float yvel = clampMag(VelocityTrackerCompat.getYVelocity(mVelocityTracker, mActivePointerId),
|
|
mMinVelocity, mMaxVelocity);
|
|
dispatchViewReleased(xvel, yvel);
|
|
}
|
|
|
|
private void reportNewEdgeDrags(final float dx, final float dy, final int pointerId) {
|
|
int dragsStarted = 0;
|
|
if (checkNewEdgeDrag(dx, dy, pointerId, EDGE_LEFT)) {
|
|
dragsStarted |= EDGE_LEFT;
|
|
}
|
|
if (checkNewEdgeDrag(dy, dx, pointerId, EDGE_TOP)) {
|
|
dragsStarted |= EDGE_TOP;
|
|
}
|
|
if (checkNewEdgeDrag(dx, dy, pointerId, EDGE_RIGHT)) {
|
|
dragsStarted |= EDGE_RIGHT;
|
|
}
|
|
if (checkNewEdgeDrag(dy, dx, pointerId, EDGE_BOTTOM)) {
|
|
dragsStarted |= EDGE_BOTTOM;
|
|
}
|
|
|
|
if (dragsStarted != 0) {
|
|
mEdgeDragsInProgress[pointerId] |= dragsStarted;
|
|
mCallback.onEdgeDragStarted(dragsStarted, pointerId);
|
|
}
|
|
}
|
|
|
|
private void saveInitialMotion(final float x, final float y, final int pointerId) {
|
|
ensureMotionHistorySizeForId(pointerId);
|
|
mInitialMotionX[pointerId] = mLastMotionX[pointerId] = x;
|
|
mInitialMotionY[pointerId] = mLastMotionY[pointerId] = y;
|
|
mInitialEdgesTouched[pointerId] = getEdgesTouched((int) x, (int) y);
|
|
mPointersDown |= 1 << pointerId;
|
|
}
|
|
|
|
private void saveLastMotion(final MotionEvent ev) {
|
|
final int pointerCount = MotionEventCompat.getPointerCount(ev);
|
|
for (int i = 0; i < pointerCount; i++) {
|
|
final int pointerId = MotionEventCompat.getPointerId(ev, i);
|
|
final float x = MotionEventCompat.getX(ev, i);
|
|
final float y = MotionEventCompat.getY(ev, i);
|
|
mLastMotionX[pointerId] = x;
|
|
mLastMotionY[pointerId] = y;
|
|
}
|
|
}
|
|
|
|
void setDragState(final int state) {
|
|
if (mDragState != state) {
|
|
mDragState = state;
|
|
mCallback.onViewDragStateChanged(state);
|
|
if (state == STATE_IDLE) {
|
|
mCapturedView = null;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Attempt to capture the view with the given pointer ID. The callback will
|
|
* be involved. This will put us into the "dragging" state. If we've already
|
|
* captured this view with this pointer this method will immediately return
|
|
* true without consulting the callback.
|
|
*
|
|
* @param toCapture View to capture
|
|
* @param pointerId Pointer to capture with
|
|
* @return true if capture was successful
|
|
*/
|
|
boolean tryCaptureViewForDrag(final View toCapture, final int pointerId) {
|
|
if (toCapture == mCapturedView && mActivePointerId == pointerId) // Already
|
|
// done!
|
|
return true;
|
|
if (toCapture != null && mCallback.tryCaptureView(toCapture, pointerId)) {
|
|
mActivePointerId = pointerId;
|
|
captureChildView(toCapture, pointerId);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Factory method to create a new ViewDragHelper.
|
|
*
|
|
* @param forParent Parent view to monitor
|
|
* @param cb Callback to provide information and receive events
|
|
* @return a new ViewDragHelper instance
|
|
*/
|
|
public static ViewDragHelper create(final ViewGroup forParent, final Callback cb) {
|
|
return new ViewDragHelper(forParent.getContext(), forParent, cb);
|
|
}
|
|
|
|
/**
|
|
* Factory method to create a new ViewDragHelper.
|
|
*
|
|
* @param forParent Parent view to monitor
|
|
* @param sensitivity Multiplier for how sensitive the helper should be
|
|
* about detecting the start of a drag. Larger values are more
|
|
* sensitive. 1.0f is normal.
|
|
* @param cb Callback to provide information and receive events
|
|
* @return a new ViewDragHelper instance
|
|
*/
|
|
public static ViewDragHelper create(final ViewGroup forParent, final float sensitivity, final Callback cb) {
|
|
final ViewDragHelper helper = create(forParent, cb);
|
|
helper.mTouchSlop = (int) (helper.mTouchSlop * (1 / sensitivity));
|
|
return helper;
|
|
}
|
|
|
|
/**
|
|
* A Callback is used as a communication channel with the ViewDragHelper
|
|
* back to the parent view using it. <code>on*</code>methods are invoked on
|
|
* siginficant events and several accessor methods are expected to provide
|
|
* the ViewDragHelper with more information about the state of the parent
|
|
* view upon request. The callback also makes decisions governing the range
|
|
* and draggability of child views.
|
|
*/
|
|
public static abstract class Callback {
|
|
/**
|
|
* Restrict the motion of the dragged child view along the horizontal
|
|
* axis. The default implementation does not allow horizontal motion;
|
|
* the extending class must override this method and provide the desired
|
|
* clamping.
|
|
*
|
|
* @param child Child view being dragged
|
|
* @param left Attempted motion along the X axis
|
|
* @param dx Proposed change in position for left
|
|
* @return The new clamped position for left
|
|
*/
|
|
public int clampViewPositionHorizontal(final View child, final int left, final int dx) {
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Restrict the motion of the dragged child view along the vertical
|
|
* axis. The default implementation does not allow vertical motion; the
|
|
* extending class must override this method and provide the desired
|
|
* clamping.
|
|
*
|
|
* @param child Child view being dragged
|
|
* @param top Attempted motion along the Y axis
|
|
* @param dy Proposed change in position for top
|
|
* @return The new clamped position for top
|
|
*/
|
|
public int clampViewPositionVertical(final View child, final int top, final int dy) {
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Called to determine the Z-order of child views.
|
|
*
|
|
* @param index the ordered position to query for
|
|
* @return index of the view that should be ordered at position
|
|
* <code>index</code>
|
|
*/
|
|
public int getOrderedChildIndex(final int index) {
|
|
return index;
|
|
}
|
|
|
|
/**
|
|
* Return the magnitude of a draggable child view's horizontal range of
|
|
* motion in pixels. This method should return 0 for views that cannot
|
|
* move horizontally.
|
|
*
|
|
* @param child Child view to check
|
|
* @return range of horizontal motion in pixels
|
|
*/
|
|
public int getViewHorizontalDragRange(final View child) {
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Return the magnitude of a draggable child view's vertical range of
|
|
* motion in pixels. This method should return 0 for views that cannot
|
|
* move vertically.
|
|
*
|
|
* @param child Child view to check
|
|
* @return range of vertical motion in pixels
|
|
*/
|
|
public int getViewVerticalDragRange(final View child) {
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Called when the user has started a deliberate drag away from one of
|
|
* the subscribed edges in the parent view while no child view is
|
|
* currently captured.
|
|
*
|
|
* @param edgeFlags A combination of edge flags describing the edge(s)
|
|
* dragged
|
|
* @param pointerId ID of the pointer touching the described edge(s)
|
|
* @see #EDGE_LEFT
|
|
* @see #EDGE_TOP
|
|
* @see #EDGE_RIGHT
|
|
* @see #EDGE_BOTTOM
|
|
*/
|
|
public void onEdgeDragStarted(final int edgeFlags, final int pointerId) {
|
|
}
|
|
|
|
/**
|
|
* Called when the given edge may become locked. This can happen if an
|
|
* edge drag was preliminarily rejected before beginning, but after
|
|
* {@link #onEdgeTouched(int, int)} was called. This method should
|
|
* return true to lock this edge or false to leave it unlocked. The
|
|
* default behavior is to leave edges unlocked.
|
|
*
|
|
* @param edgeFlags A combination of edge flags describing the edge(s)
|
|
* locked
|
|
* @return true to lock the edge, false to leave it unlocked
|
|
*/
|
|
public boolean onEdgeLock(final int edgeFlags) {
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Called when one of the subscribed edges in the parent view has been
|
|
* touched by the user while no child view is currently captured.
|
|
*
|
|
* @param edgeFlags A combination of edge flags describing the edge(s)
|
|
* currently touched
|
|
* @param pointerId ID of the pointer touching the described edge(s)
|
|
* @see #EDGE_LEFT
|
|
* @see #EDGE_TOP
|
|
* @see #EDGE_RIGHT
|
|
* @see #EDGE_BOTTOM
|
|
*/
|
|
public void onEdgeTouched(final int edgeFlags, final int pointerId) {
|
|
}
|
|
|
|
/**
|
|
* Called when a child view is captured for dragging or settling. The ID
|
|
* of the pointer currently dragging the captured view is supplied. If
|
|
* activePointerId is identified as {@link #INVALID_POINTER} the capture
|
|
* is programmatic instead of pointer-initiated.
|
|
*
|
|
* @param capturedChild Child view that was captured
|
|
* @param activePointerId Pointer id tracking the child capture
|
|
*/
|
|
public void onViewCaptured(final View capturedChild, final int activePointerId) {
|
|
}
|
|
|
|
/**
|
|
* Called when the drag state changes. See the <code>STATE_*</code>
|
|
* constants for more information.
|
|
*
|
|
* @param state The new drag state
|
|
* @see #STATE_IDLE
|
|
* @see #STATE_DRAGGING
|
|
* @see #STATE_SETTLING
|
|
*/
|
|
public void onViewDragStateChanged(final int state) {
|
|
}
|
|
|
|
/**
|
|
* Called when the captured view's position changes as the result of a
|
|
* drag or settle.
|
|
*
|
|
* @param changedView View whose position changed
|
|
* @param left New X coordinate of the left edge of the view
|
|
* @param top New Y coordinate of the top edge of the view
|
|
* @param dx Change in X position from the last call
|
|
* @param dy Change in Y position from the last call
|
|
*/
|
|
public void onViewPositionChanged(final View changedView, final int left, final int top, final int dx,
|
|
final int dy) {
|
|
}
|
|
|
|
/**
|
|
* Called when the child view is no longer being actively dragged. The
|
|
* fling velocity is also supplied, if relevant. The velocity values may
|
|
* be clamped to system minimums or maximums.
|
|
* <p>
|
|
* Calling code may decide to fling or otherwise release the view to let
|
|
* it settle into place. It should do so using
|
|
* {@link #settleCapturedViewAt(int, int)} or
|
|
* {@link #flingCapturedView(int, int, int, int)}. If the Callback
|
|
* invokes one of these methods, the ViewDragHelper will enter
|
|
* {@link #STATE_SETTLING} and the view capture will not fully end until
|
|
* it comes to a complete stop. If neither of these methods is invoked
|
|
* before <code>onViewReleased</code> returns, the view will stop in
|
|
* place and the ViewDragHelper will return to {@link #STATE_IDLE}.
|
|
* </p>
|
|
*
|
|
* @param releasedChild The captured child view now being released
|
|
* @param xvel X velocity of the pointer as it left the screen in pixels
|
|
* per second.
|
|
* @param yvel Y velocity of the pointer as it left the screen in pixels
|
|
* per second.
|
|
*/
|
|
public void onViewReleased(final View releasedChild, final float xvel, final float yvel) {
|
|
}
|
|
|
|
/**
|
|
* Called when the user's input indicates that they want to capture the
|
|
* given child view with the pointer indicated by pointerId. The
|
|
* callback should return true if the user is permitted to drag the
|
|
* given view with the indicated pointer.
|
|
* <p>
|
|
* ViewDragHelper may call this method multiple times for the same view
|
|
* even if the view is already captured; this indicates that a new
|
|
* pointer is trying to take control of the view.
|
|
* </p>
|
|
* <p>
|
|
* If this method returns true, a call to
|
|
* {@link #onViewCaptured(android.view.View, int)} will follow if the
|
|
* capture is successful.
|
|
* </p>
|
|
*
|
|
* @param child Child the user is attempting to capture
|
|
* @param pointerId ID of the pointer attempting the capture
|
|
* @return true if capture should be allowed, false otherwise
|
|
*/
|
|
public abstract boolean tryCaptureView(View child, int pointerId);
|
|
}
|
|
}
|