Allow "new posts" button to be swiped away

mastodon/src/main/java/org/joinmastodon/android/fragments/HomeTimelineFragment.java

@@ -4,6 +4,7 @@ import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
+import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
@@ -34,7 +35,6 @@ import android.widget.Toolbar;
 
 import com.squareup.otto.Subscribe;
 
-import org.joinmastodon.android.BuildConfig;
 import org.joinmastodon.android.E;
 import org.joinmastodon.android.R;
 import org.joinmastodon.android.api.MastodonAPIRequest;
@@ -61,6 +61,7 @@ import org.joinmastodon.android.ui.utils.DiscoverInfoBannerHelper;
 import org.joinmastodon.android.ui.viewcontrollers.HomeTimelineMenuController;
 import org.joinmastodon.android.ui.viewcontrollers.ToolbarDropdownMenuController;
 import org.joinmastodon.android.ui.views.FixedAspectRatioImageView;
+import org.joinmastodon.android.ui.views.NewPostsButtonContainer;
 import org.joinmastodon.android.updater.GithubSelfUpdater;
 import org.parceler.Parcels;
 
@@ -89,7 +90,7 @@ public class HomeTimelineFragment extends StatusListFragment implements ToolbarD
 	private FixedAspectRatioImageView listsDropdownArrow;
 	private TextView listsDropdownText;
 	private Button newPostsBtn;
-	private View newPostsBtnWrap;
+	private NewPostsButtonContainer newPostsBtnWrap;
 	private boolean newPostsBtnShown;
 	private AnimatorSet currentNewPostsAnim;
 	private ToolbarDropdownMenuController dropdownController;
@@ -249,6 +250,7 @@ public class HomeTimelineFragment extends StatusListFragment implements ToolbarD
 		}
 	}
 
+	@SuppressLint("ClickableViewAccessibility")
 	@Override
 	public void onViewCreated(View view, Bundle savedInstanceState){
 		super.onViewCreated(view, savedInstanceState);
@@ -267,6 +269,7 @@ public class HomeTimelineFragment extends StatusListFragment implements ToolbarD
 			newPostsBtnWrap.setAlpha(0f);
 			newPostsBtnWrap.setTranslationY(V.dp(-56));
 		}
+		newPostsBtnWrap.setOnHideButtonListener(this::hideNewPostsButton);
 		updateToolbarLogo();
 		list.addOnScrollListener(new RecyclerView.OnScrollListener(){
 			@Override
@@ -602,6 +605,7 @@ public class HomeTimelineFragment extends StatusListFragment implements ToolbarD
 			@Override
 			public void onAnimationEnd(Animator animation){
 				newPostsBtnWrap.setVisibility(View.GONE);
+				newPostsBtn.setTranslationY(0);
 				currentNewPostsAnim=null;
 			}
 		});

mastodon/src/main/java/org/joinmastodon/android/ui/views/NewPostsButtonContainer.java

@@ -0,0 +1,84 @@
+package org.joinmastodon.android.ui.views;
+
+import android.annotation.SuppressLint;
+import android.content.Context;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.GestureDetector;
+import android.view.MotionEvent;
+import android.view.ViewConfiguration;
+import android.widget.FrameLayout;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import me.grishka.appkit.utils.CubicBezierInterpolator;
+
+public class NewPostsButtonContainer extends FrameLayout{
+	private GestureDetector gestureDetector;
+	private Runnable onHideButtonListener;
+	private float touchslop;
+
+	public NewPostsButtonContainer(Context context){
+		this(context, null);
+	}
+
+	public NewPostsButtonContainer(Context context, AttributeSet attrs){
+		this(context, attrs, 0);
+	}
+
+	public NewPostsButtonContainer(Context context, AttributeSet attrs, int defStyle){
+		super(context, attrs, defStyle);
+		gestureDetector=new GestureDetector(context, new GestureDetector.SimpleOnGestureListener(){
+			private float totalYOffset;
+
+			@Override
+			public boolean onDown(@NonNull MotionEvent e){
+				totalYOffset=0;
+				getChildAt(0).animate().cancel();
+				return false;
+			}
+
+			@Override
+			public boolean onScroll(@Nullable MotionEvent e1, @NonNull MotionEvent e2, float distanceX, float distanceY){
+				totalYOffset+=distanceY;
+				getChildAt(0).setTranslationY(-Math.max(0, totalYOffset));
+				return totalYOffset>0;
+			}
+		});
+		gestureDetector.setIsLongpressEnabled(false);
+		touchslop=ViewConfiguration.get(context).getScaledTouchSlop();
+	}
+
+	@Override
+	public boolean onInterceptTouchEvent(MotionEvent ev){
+		if(gestureDetector.onTouchEvent(ev))
+			return true;
+		return super.onInterceptTouchEvent(ev);
+	}
+
+	@SuppressLint("ClickableViewAccessibility")
+	@Override
+	public boolean onTouchEvent(MotionEvent ev){
+		boolean r=gestureDetector.onTouchEvent(ev);
+		if(ev.getAction()==MotionEvent.ACTION_UP){
+			if(!r){
+				if(getChildAt(0).getTranslationY()<-touchslop){
+					onHideButtonListener.run();
+				}else{
+					animateBack();
+				}
+			}
+		}else if(ev.getAction()==MotionEvent.ACTION_CANCEL){
+			animateBack();
+		}
+		return r;
+	}
+
+	private void animateBack(){
+		getChildAt(0).animate().translationY(0).setDuration(150).setInterpolator(CubicBezierInterpolator.DEFAULT).start();
+	}
+
+	public void setOnHideButtonListener(Runnable onHideButtonListener){
+		this.onHideButtonListener=onHideButtonListener;
+	}
+}

mastodon/src/main/res/layout/fragment_timeline.xml

@@ -34,7 +34,7 @@
 			android:contentDescription="@string/new_post"
 			android:src="@drawable/ic_edit_24px"/>
 
-		<FrameLayout
+		<org.joinmastodon.android.ui.views.NewPostsButtonContainer
 			android:id="@+id/new_posts_btn_wrap"
 			android:layout_width="wrap_content"
 			android:layout_height="wrap_content"
@@ -56,7 +56,7 @@
 				android:elevation="@dimen/m3_sys_elevation_level4"
 				android:stateListAnimator="@animator/squish"
 				android:text="@string/see_new_posts"/>
-		</FrameLayout>
+		</org.joinmastodon.android.ui.views.NewPostsButtonContainer>
 
 		<ViewStub
 			android:id="@+id/donation_banner"