content: // THIS IS A BETA! I DON'T RECOMMEND USING IT IN PRODUCTION CODE JUST YET
  
  /*
   * Copyright 2012 Roman Nurik
   * Copyright 2013 Niek Haarman
   *
   * 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 com.haarman.listviewanimations.itemmanipulation;
  
  //import static com.nineoldandroids.view.ViewHelper.setAlpha;
  import static com.nineoldandroids.view.ViewPropertyAnimator.animate;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import android.annotation.SuppressLint;
  import android.graphics.Rect;
  import android.util.Log;
  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.ListView;
  
  import com.nineoldandroids.animation.Animator;
  import com.nineoldandroids.animation.AnimatorListenerAdapter;
  import com.nineoldandroids.animation.ValueAnimator;
  import com.nineoldandroids.view.ViewHelper;
  
  /**
   * 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.
   *
   * For performance reasons, do not use this class directly, but use the {@link SwipeDismissAdapter}.
   */
  @SuppressLint("Recycle")
  public class SwipeDismissListViewTouchListener implements SwipeOnTouchListener {
  
  	// Cached ViewConfiguration and system-wide constant values
  	private int mSlop;
  	private int mMinFlingVelocity;
  	private int mMaxFlingVelocity;
  	protected long mAnimationTime;
  
  	// Fixed properties
  	private AbsListView mListView;
  	private OnDismissCallback mCallback;
  	private int mViewWidth = 1; // 1 and not 0 to prevent dividing by zero
  
  	// Transient properties
  	protected List<PendingDismissData> mPendingDismisses = new ArrayList<PendingDismissData>();
  	private int mDismissAnimationRefCount = 0;
  	private float mDownX;
  	private float mDownY;
  	private boolean mSwiping;
  
  	/**
  	 * A state to help determine the first loop/time we are swiping
  	 */
  	private boolean mSwipeInitiated;
  	private VelocityTracker mVelocityTracker;
  	private boolean mPaused;
  	private PendingDismissData mCurrentDismissData;
  
  	private int mVirtualListCount = -1;
  
  	private boolean mDisallowSwipe;
  	private boolean mIsParentHorizontalScrollContainer;
  	private int mResIdOfTouchChild;
  	private boolean mTouchChildTouched;
  
  	/**
  	 * 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(AbsListView listView, OnDismissCallback callback, SwipeOnScrollListener onScroll) {
  		ViewConfiguration vc = ViewConfiguration.get(listView.getContext());
  		mSlop = vc.getScaledTouchSlop();
  		mMinFlingVelocity = vc.getScaledMinimumFlingVelocity() * 16;
  		mMaxFlingVelocity = vc.getScaledMaximumFlingVelocity();
  		mAnimationTime = listView.getContext().getResources().getInteger(android.R.integer.config_shortAnimTime);
  		mListView = listView;
  		mCallback = callback;
  
  		onScroll.setTouchListener(this);
  		mListView.setOnScrollListener(onScroll);
  	}
  
  	public void disallowSwipe() {
  		mDisallowSwipe = true;
  	}
  
  	public void allowSwipe() {
  		mDisallowSwipe = false;
  	}
  
  	@Override
  	public boolean onTouch(View view, MotionEvent motionEvent) {
  		if (mVirtualListCount == -1) {
  			mVirtualListCount = mListView.getAdapter().getCount();
  		}
  
  		if (mViewWidth < 2) {
  			mViewWidth = mListView.getWidth();
  		}
  
  		switch (motionEvent.getActionMasked()) {
  		case MotionEvent.ACTION_DOWN:
  
  			mDisallowSwipe = false;
  			view.onTouchEvent(motionEvent);
  			return handleDownEvent(motionEvent);
  
  		case MotionEvent.ACTION_MOVE:
  
  			return handleMoveEvent(motionEvent);
  
  		case MotionEvent.ACTION_UP:
  		case MotionEvent.ACTION_CANCEL:
  
  			mDisallowSwipe = false;
  			mTouchChildTouched = false;
  			return handleUpEvent(motionEvent);
  
  		}
  		return false;
  	}
  
  	@Override
  	public boolean isSwiping() {
  		return mSwiping;
  	}
  
  	/**
  	 * Factory to allow override of dismiss data
  	 */
  	protected PendingDismissData createPendingDismissData(int position, View view) {
  		return new PendingDismissData(position, view);
  	}
  
  	private boolean handleDownEvent(MotionEvent motionEvent) {
  		if (mPaused) {
  			return false;
  		}
  
  		mSwipeInitiated = false;
  
  		// 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 downView = null;
  		for (int i = 0; i < childCount && downView == null; i++) {
  			View child = mListView.getChildAt(i);
  			child.getHitRect(rect);
  			if (rect.contains(x, y)) {
  				downView = child;
  			}
  		}
  
  		if (downView != null) {
  			Log.d("SwipeDismissListViewTouchListener", "hit child !");
  			mDownX = motionEvent.getRawX();
  			mDownY = motionEvent.getRawY();
  			int downPosition = mListView.getPositionForView(downView);
  
  			mCurrentDismissData = createPendingDismissData(downPosition, downView);
  
  			if (mPendingDismisses.contains(mCurrentDismissData) || downPosition >= mVirtualListCount) {
  				// Cancel, we're already processing this position
  				mCurrentDismissData = null;
  				return false;
  			} else {
  				mTouchChildTouched = !mIsParentHorizontalScrollContainer && (mResIdOfTouchChild == 0);
  
  				if (mResIdOfTouchChild != 0) {
  					mIsParentHorizontalScrollContainer = false;
  
  					final View childView = downView.findViewById(mResIdOfTouchChild);
  					if (childView != null) {
  						final Rect childRect = getChildViewRect(mListView, childView);
  						if (childRect.contains((int) mDownX, (int) mDownY)) {
  							mTouchChildTouched = true;
  							mListView.requestDisallowInterceptTouchEvent(true);
  						}
  					}
  				}
  
  				if (mIsParentHorizontalScrollContainer) {
  					// Do it now and don't wait until the user moves more than
  					// the slop factor.
  					mTouchChildTouched = true;
  					mListView.requestDisallowInterceptTouchEvent(true);
  				}
  
  				mVelocityTracker = VelocityTracker.obtain();
  				mVelocityTracker.addMovement(motionEvent);
  			}
  		}
  		return true;
  	}
  
  	private Rect getChildViewRect(View parentView, View childView) {
  		final Rect childRect = new Rect(childView.getLeft(), childView.getTop(), childView.getRight(), childView.getBottom());
  		if (parentView == childView) {
  			return childRect;
  
  		}
  
  		ViewGroup parent;
  		while ((parent = (ViewGroup) childView.getParent()) != parentView) {
  			childRect.offset(parent.getLeft(), parent.getTop());
  			childView = parent;
  		}
  
  		return childRect;
  	}
  
  	private boolean handleMoveEvent(MotionEvent motionEvent) {
  		if (mPaused || (mVelocityTracker == null)) {
  			return false;
  		}
  
  		mVelocityTracker.addMovement(motionEvent);
  		float deltaX = motionEvent.getRawX() - mDownX;
  		float deltaY = motionEvent.getRawY() - mDownY;
  		if (mTouchChildTouched && !mDisallowSwipe && Math.abs(deltaX) > mSlop && Math.abs(deltaX) > Math.abs(deltaY)) {
  			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);
  		}
  
  		if (mSwiping) {
  			if (!mSwipeInitiated) {
  				Log.d("SwipeDismissListViewTouchListener", "swipe/begin");
  			}
  			mSwipeInitiated = true;
  			ViewHelper.setTranslationX(mCurrentDismissData.view, deltaX);
  			ViewHelper.setAlpha(mCurrentDismissData.view, Math.max(0f, Math.min(1f, 1f - 2f * Math.abs(deltaX) / mViewWidth)));
  			return true;
  		}
  		return false;
  	}
  
  	private boolean handleUpEvent(MotionEvent motionEvent) {
  		if (mVelocityTracker == null) {
  			return false;
  		}
  
  		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 (mSwiping) {
  			if (dismiss) {
  				Log.d("SwipeDismissListViewTouchListener", "swipe/confimed");
  				// mDownView gets null'd before animation ends
  				final PendingDismissData pendingDismissData = mCurrentDismissData;
  				++mDismissAnimationRefCount;
  
  				animate(mCurrentDismissData.view).translationX(dismissRight ? mViewWidth : -mViewWidth).alpha(0).setDuration(mAnimationTime).setListener(new AnimatorListenerAdapter() {
  
  					@Override
  					public void onAnimationEnd(Animator animation) {
  						onDismiss(pendingDismissData);
  					}
  				});
  
  				mVirtualListCount--;
  				mPendingDismisses.add(mCurrentDismissData);
  			} else {
  				Log.d("SwipeDismissListViewTouchListener", "swipe/cancelled");
  				// cancel
  				animate(mCurrentDismissData.view).translationX(0).alpha(1).setDuration(mAnimationTime).setListener(null);
  			}
  		}
  
  		mVelocityTracker.recycle();
  		mVelocityTracker = null;
  		mDownX = 0;
  		mCurrentDismissData = null;
  		mSwiping = false;
  		return false;
  	}
  
  	protected class PendingDismissData implements Comparable<PendingDismissData> {
  		public int position;
  		public View view;
  
  		public PendingDismissData(int position, View view) {
  			this.position = position;
  			this.view = view;
  		}
  
  		@Override
  		public int compareTo(PendingDismissData other) {
  			// Sort by descending position
  			return other.position - position;
  		}
  
  		@Override
  		public int hashCode() {
  			final int prime = 31;
  			int result = 1;
  			result = prime * result + position;
  			return result;
  		}
  
  		@Override
  		public boolean equals(Object obj) {
  			if (this == obj)
  				return true;
  			if (obj == null)
  				return false;
  			if (((Object) this).getClass() != obj.getClass())
  				return false;
  			PendingDismissData other = (PendingDismissData) obj;
  			if (position != other.position)
  				return false;
  			return true;
  		}
  
  	}
  
  	protected void onDismiss(final PendingDismissData data) {
  		// default behaviour
  		performDismiss(data);
  	}
  
  	protected void performDismiss(final PendingDismissData data) {
  		// Animate the dismissed list item to zero-height and fire the
  		// dismiss callback when all dismissed list item animations have
  		// completed.
  
  		Log.d("SwipeDismissListViewTouchListener", "performDismiss");
  
  		final ViewGroup.LayoutParams lp = data.view.getLayoutParams();
  		final int originalHeight = data.view.getHeight();
  
  		ValueAnimator animator = ValueAnimator.ofInt(originalHeight, 1).setDuration(mAnimationTime);
  
  		animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
  			@Override
  			public void onAnimationUpdate(ValueAnimator valueAnimator) {
  				lp.height = (Integer) valueAnimator.getAnimatedValue();
  				data.view.setLayoutParams(lp);
  			}
  		});
  
  		animator.addListener(new AnimatorListenerAdapter() {
  			@Override
  			public void onAnimationEnd(Animator animation) {
  				finalizeDismiss();
  			}
  		});
  		animator.start();
  	}
  
  	/**
  	 * Here you can manage dismissed View.
  	 */
  	protected void recycleDismissedViewsItems(List<PendingDismissData> pendingDismisses) {
  		ViewGroup.LayoutParams lp;
  		for (PendingDismissData pendingDismiss : pendingDismisses) {
  			// Reset view presentation
  			ViewHelper.setAlpha(pendingDismiss.view, 1f);
  			ViewHelper.setTranslationX(pendingDismiss.view, 0);
  			lp = pendingDismiss.view.getLayoutParams();
  			lp.height = 0;
  			pendingDismiss.view.setLayoutParams(lp);
  		}
  	}
  
  	protected void finalizeDismiss() {
  
  		--mDismissAnimationRefCount;
  		if (mDismissAnimationRefCount == 0) {
  			// No active animations, process all pending dismisses.
  			// Sort by descending position
  			Collections.sort(mPendingDismisses);
  
  			int[] dismissPositions = new int[mPendingDismisses.size()];
  			for (int i = mPendingDismisses.size() - 1; i >= 0; i--) {
  				dismissPositions[i] = mPendingDismisses.get(i).position;
  			}
  			mCallback.onDismiss(mListView, dismissPositions);
  
  			recycleDismissedViewsItems(mPendingDismisses);
  
  			mPendingDismisses.clear();
  		}
  	}
  
  	void setIsParentHorizontalScrollContainer(boolean isParentHorizontalScrollContainer) {
  		mIsParentHorizontalScrollContainer = (mResIdOfTouchChild == 0) ? isParentHorizontalScrollContainer : false;
  	}
  
  	void setTouchChild(int childResId) {
  		mResIdOfTouchChild = childResId;
  		if (childResId != 0) {
  			setIsParentHorizontalScrollContainer(false);
  		}
  	}
  
  	public void notifyDataSetChanged() {
  		mVirtualListCount = mListView.getAdapter().getCount();
  	}
  }
  