111 lines
3.6 KiB
Java
111 lines
3.6 KiB
Java
/*
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* Twidere - Twitter client for Android
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*
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* Copyright (C) 2012-2015 Mariotaku Lee <mariotaku.lee@gmail.com>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package org.mariotaku.twidere.util;
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import android.support.annotation.NonNull;
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import android.support.v7.widget.RecyclerView;
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import android.support.v7.widget.RecyclerView.OnScrollListener;
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import org.apache.commons.lang3.ArrayUtils;
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import org.mariotaku.twidere.adapter.iface.ILoadMoreSupportAdapter;
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/**
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* Created by mariotaku on 15/3/15.
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*/
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public class ContentListScrollListener extends OnScrollListener {
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private int mScrollState;
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private int mScrollSum;
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private int mTouchSlop;
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private ContentListSupport mContentListSupport;
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public ContentListScrollListener(@NonNull ContentListSupport contentListSupport) {
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mContentListSupport = contentListSupport;
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}
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@Override
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public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
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if (mScrollState != RecyclerView.SCROLL_STATE_IDLE) {
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notifyScrollStateChanged();
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}
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mScrollState = newState;
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}
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@Override
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public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
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//Reset mScrollSum when scrolling in reverse direction
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if (dy * mScrollSum < 0) {
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mScrollSum = 0;
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}
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mScrollSum += dy;
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if (Math.abs(mScrollSum) > mTouchSlop) {
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mContentListSupport.setControlVisible(dy < 0);
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mScrollSum = 0;
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}
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if (recyclerView.getScrollState() == RecyclerView.SCROLL_STATE_IDLE) {
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notifyScrollStateChanged();
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}
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}
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public void setTouchSlop(int touchSlop) {
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mTouchSlop = touchSlop;
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}
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private void notifyScrollStateChanged() {
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final Object adapter = mContentListSupport.getAdapter();
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if (!(adapter instanceof ILoadMoreSupportAdapter)) return;
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final ILoadMoreSupportAdapter loadMoreAdapter = (ILoadMoreSupportAdapter) adapter;
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if (!mContentListSupport.isRefreshing() && loadMoreAdapter.isLoadMoreSupported()
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&& !loadMoreAdapter.isLoadMoreIndicatorVisible()) {
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if (reachedEnd()) {
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mContentListSupport.onLoadMoreContents(false);
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} else if (reachedStart()) {
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mContentListSupport.onLoadMoreContents(true);
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}
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}
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}
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private boolean reachedStart() {
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return ArrayUtils.contains(mContentListSupport.findFirstVisibleItemPositions(), 0);
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}
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private boolean reachedEnd() {
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return ArrayUtils.contains(mContentListSupport.findLastVisibleItemPositions(), mContentListSupport.getItemCount() - 1);
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}
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public interface ContentListSupport {
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Object getAdapter();
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boolean isRefreshing();
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void onLoadMoreContents(boolean fromStart);
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void setControlVisible(boolean visible);
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int[] findLastVisibleItemPositions();
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int[] findFirstVisibleItemPositions();
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int getItemCount();
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}
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}
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