/* * Copyright 2012 Roman Nurik * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.mozilla.gecko.widget; import android.graphics.Rect; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.widget.AbsListView; import android.widget.AbsListView.RecyclerListener; import android.widget.ListView; import android.animation.Animator; import android.animation.AnimatorListenerAdapter; import android.animation.ValueAnimator; import android.view.ViewPropertyAnimator; import org.mozilla.gecko.R; /** * This code is based off of Jake Wharton's NOA port (https://github.com/JakeWharton/SwipeToDismissNOA) * of Roman Nurik's SwipeToDismiss library. It has been modified for better support with async * adapters. * * A {@link android.view.View.OnTouchListener} that makes the list items in a {@link ListView} * dismissable. {@link ListView} is given special treatment because by default it handles touches * for its list items... i.e. it's in charge of drawing the pressed state (the list selector), * handling list item clicks, etc. * *
After creating the listener, the caller should also call * {@link ListView#setOnScrollListener(android.widget.AbsListView.OnScrollListener)}, passing * in the scroll listener returned by {@link #makeScrollListener()}. If a scroll listener is * already assigned, the caller should still pass scroll changes through to this listener. This will * ensure that this {@link SwipeDismissListViewTouchListener} is paused during list view * scrolling.
* *Example usage:
* ** SwipeDismissListViewTouchListener touchListener = * new SwipeDismissListViewTouchListener( * listView, * new SwipeDismissListViewTouchListener.OnDismissCallback() { * public void onDismiss(ListView listView, int[] reverseSortedPositions) { * for (int position : reverseSortedPositions) { * adapter.remove(adapter.getItem(position)); * } * adapter.notifyDataSetChanged(); * } * }); * listView.setOnTouchListener(touchListener); * listView.setOnScrollListener(touchListener.makeScrollListener()); ** *
For a generalized {@link android.view.View.OnTouchListener} that makes any view dismissable, * see {@link SwipeDismissTouchListener}.
* * @see SwipeDismissTouchListener */ public class SwipeDismissListViewTouchListener implements View.OnTouchListener { // Cached ViewConfiguration and system-wide constant values private final int mSlop; private final int mMinFlingVelocity; private final int mMaxFlingVelocity; private final long mAnimationTime; // Fixed properties private final ListView mListView; private final OnDismissCallback mCallback; private int mViewWidth = 1; // 1 and not 0 to prevent dividing by zero // Transient properties private float mDownX; private boolean mSwiping; private VelocityTracker mVelocityTracker; private int mDownPosition; private View mDownView; private boolean mPaused; private boolean mDismissing; /** * The callback interface used by {@link SwipeDismissListViewTouchListener} to inform its client * about a successful dismissal of a list item. */ public interface OnDismissCallback { /** * Called when the user has indicated they she would like to dismiss one or more list item * positions. * * @param listView The originating {@link ListView}. * @param position The position being dismissed. */ void onDismiss(ListView listView, int position); } /** * Constructs a new swipe-to-dismiss touch listener for the given list view. * * @param listView The list view whose items should be dismissable. * @param callback The callback to trigger when the user has indicated that she would like to * dismiss one or more list items. */ public SwipeDismissListViewTouchListener(ListView listView, OnDismissCallback callback) { ViewConfiguration vc = ViewConfiguration.get(listView.getContext()); mSlop = vc.getScaledTouchSlop(); mMinFlingVelocity = vc.getScaledMinimumFlingVelocity(); mMaxFlingVelocity = vc.getScaledMaximumFlingVelocity(); mAnimationTime = listView.getContext().getResources().getInteger( android.R.integer.config_shortAnimTime); mListView = listView; mCallback = callback; } /** * Enables or disables (pauses or resumes) watching for swipe-to-dismiss gestures. * * @param enabled Whether or not to watch for gestures. */ public void setEnabled(boolean enabled) { mPaused = !enabled; } /** * Returns an {@link android.widget.AbsListView.OnScrollListener} to be added to the * {@link ListView} using * {@link ListView#setOnScrollListener(android.widget.AbsListView.OnScrollListener)}. * If a scroll listener is already assigned, the caller should still pass scroll changes * through to this listener. This will ensure that this * {@link SwipeDismissListViewTouchListener} is paused during list view scrolling. * * @see {@link SwipeDismissListViewTouchListener} */ public AbsListView.OnScrollListener makeScrollListener() { return new AbsListView.OnScrollListener() { @Override public void onScrollStateChanged(AbsListView absListView, int scrollState) { setEnabled(scrollState != AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL); } @Override public void onScroll(AbsListView absListView, int i, int i1, int i2) { } }; } /** * Returns a {@link android.widget.AbsListView.RecyclerListener} to be added to the * {@link ListView} using {@link ListView#setRecyclerListener(RecyclerListener)}. */ public AbsListView.RecyclerListener makeRecyclerListener() { return new AbsListView.RecyclerListener() { @Override public void onMovedToScrapHeap(View view) { final Object tag = view.getTag(R.id.original_height); // To reset the view to the correct height after its animation, the view's height // is stored in its tag. Reset the view here. if (tag instanceof Integer) { view.setAlpha(1f); view.setTranslationX(0); final ViewGroup.LayoutParams lp = view.getLayoutParams(); lp.height = (int) tag; view.setLayoutParams(lp); view.setTag(R.id.original_height, null); } } }; } @Override public boolean onTouch(View view, MotionEvent motionEvent) { if (mViewWidth < 2) { mViewWidth = mListView.getWidth(); } switch (motionEvent.getActionMasked()) { case MotionEvent.ACTION_DOWN: { if (mPaused) { return false; } if (mDismissing) { return true; } // TODO: ensure this is a finger, and set a flag // Find the child view that was touched (perform a hit test) Rect rect = new Rect(); int childCount = mListView.getChildCount(); int[] listViewCoords = new int[2]; mListView.getLocationOnScreen(listViewCoords); int x = (int) motionEvent.getRawX() - listViewCoords[0]; int y = (int) motionEvent.getRawY() - listViewCoords[1]; View child; for (int i = 0; i < childCount; i++) { child = mListView.getChildAt(i); child.getHitRect(rect); if (rect.contains(x, y)) { mDownView = child; break; } } if (mDownView != null) { mDownX = motionEvent.getRawX(); mDownPosition = mListView.getPositionForView(mDownView); mVelocityTracker = VelocityTracker.obtain(); mVelocityTracker.addMovement(motionEvent); } view.onTouchEvent(motionEvent); return true; } case MotionEvent.ACTION_UP: { if (mVelocityTracker == null) { break; } float deltaX = motionEvent.getRawX() - mDownX; mVelocityTracker.addMovement(motionEvent); mVelocityTracker.computeCurrentVelocity(1000); float velocityX = Math.abs(mVelocityTracker.getXVelocity()); float velocityY = Math.abs(mVelocityTracker.getYVelocity()); boolean dismiss = false; boolean dismissRight = false; if (Math.abs(deltaX) > mViewWidth / 2) { dismiss = true; dismissRight = deltaX > 0; } else if (mMinFlingVelocity <= velocityX && velocityX <= mMaxFlingVelocity && velocityY < velocityX) { dismiss = true; dismissRight = mVelocityTracker.getXVelocity() > 0; } if (dismiss) { // dismiss mDismissing = true; final View downView = mDownView; // mDownView gets null'd before animation ends final int downPosition = mDownPosition; mDownView.animate() .translationX(dismissRight ? mViewWidth : -mViewWidth) .alpha(0) .setDuration(mAnimationTime) .setListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { performDismiss(downView, downPosition); } }); } else { // cancel mDownView.animate() .translationX(0) .alpha(1) .setDuration(mAnimationTime) .setListener(null); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } mDownX = 0; mDownView = null; mDownPosition = ListView.INVALID_POSITION; mSwiping = false; break; } case MotionEvent.ACTION_MOVE: { if (mVelocityTracker == null || mPaused) { break; } mVelocityTracker.addMovement(motionEvent); float deltaX = motionEvent.getRawX() - mDownX; if (Math.abs(deltaX) > mSlop) { mSwiping = true; mListView.requestDisallowInterceptTouchEvent(true); // Cancel ListView's touch (un-highlighting the item) MotionEvent cancelEvent = MotionEvent.obtain(motionEvent); cancelEvent.setAction(MotionEvent.ACTION_CANCEL | (motionEvent.getActionIndex() << MotionEvent.ACTION_POINTER_INDEX_SHIFT)); mListView.onTouchEvent(cancelEvent); cancelEvent.recycle(); } if (mSwiping) { mDownView.setTranslationX(deltaX); mDownView.setAlpha(Math.max(0f, Math.min(1f, 1f - 2f * Math.abs(deltaX) / mViewWidth))); return true; } break; } } return false; } /** * Animate the dismissed list item to zero-height and fire the dismiss callback when it finishes. * * @param dismissView ListView item to dismiss * @param dismissPosition Position of dismissed item */ private void performDismiss(final View dismissView, final int dismissPosition) { final ViewGroup.LayoutParams lp = dismissView.getLayoutParams(); final int originalHeight = lp.height; ValueAnimator animator = ValueAnimator.ofInt(dismissView.getHeight(), 1).setDuration(mAnimationTime); animator.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { // Since the view is still a part of the ListView, we can't reset the animated // properties yet; otherwise, the view would briefly reappear. Store the original // height in the view's tag to flag it for the recycler. This is racy since the user // could scroll the dismissed view off the screen, then back on the screen, before // it's removed from the adapter, causing the dismissed view to briefly reappear. dismissView.setTag(R.id.original_height, originalHeight); mCallback.onDismiss(mListView, dismissPosition); mDismissing = false; } }); animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator valueAnimator) { lp.height = (Integer) valueAnimator.getAnimatedValue(); dismissView.setLayoutParams(lp); } }); animator.start(); } }