SwipeDismissListViewTouchListener.java

// 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.marshalchen.common.uimodule.listviewanimations.itemmanipulation.swipedismiss;

import android.annotation.SuppressLint;
import android.graphics.Rect;
import android.view.*;
import android.widget.AbsListView;
import com.marshalchen.common.uimodule.listviewanimations.itemmanipulation.OnDismissCallback;
import com.marshalchen.common.uimodule.listviewanimations.util.AdapterViewUtil;
import com.marshalchen.common.uimodule.nineoldandroids.animation.Animator;
import com.marshalchen.common.uimodule.nineoldandroids.animation.AnimatorListenerAdapter;
import com.marshalchen.common.uimodule.nineoldandroids.animation.ValueAnimator;
import com.marshalchen.common.uimodule.nineoldandroids.view.ViewHelper;
import com.marshalchen.common.uimodule.nineoldandroids.view.ViewPropertyAnimator;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import static com.marshalchen.common.uimodule.nineoldandroids.view.ViewPropertyAnimator.animate;

/**
 * A {@link android.view.View.OnTouchListener} that makes the list items in a
 * {@link android.widget.ListView} dismissable. {@link android.widget.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 com.marshalchen.common.uimodule.listviewanimations.itemmanipulation.swipedismiss.SwipeDismissAdapter}.
 */
@SuppressLint("Recycle")
public class SwipeDismissListViewTouchListener implements SwipeOnTouchListener {

    private static final int MIN_FLING_VELOCITY_FACTOR = 16;
    // Cached ViewConfiguration and system-wide constant values
    private final int mSlop;
    private final int mMinFlingVelocity;
    private final int mMaxFlingVelocity;
    protected long mAnimationTime;

    // Fixed properties
    private final AbsListView mListView;
    private final 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;

    private VelocityTracker mVelocityTracker;
    private PendingDismissData mCurrentDismissData;

    private int mVirtualListCount = -1;

    private boolean mDisallowSwipe;
    private boolean mIsParentHorizontalScrollContainer;
    private int mResIdOfTouchChild;
    private boolean mTouchChildTouched;

    private DismissableManager mDismissableManager;

    /**
     * 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(final AbsListView listView, final OnDismissCallback callback, final SwipeOnScrollListener onScroll) {
        ViewConfiguration vc = ViewConfiguration.get(listView.getContext());
        mSlop = vc.getScaledTouchSlop();
        mMinFlingVelocity = vc.getScaledMinimumFlingVelocity() * MIN_FLING_VELOCITY_FACTOR;
        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;
    }

    @SuppressWarnings("UnusedDeclaration")
    public void allowSwipe() {
        mDisallowSwipe = false;
    }

    /**
     * Set the {@link com.marshalchen.common.uimodule.listviewanimations.itemmanipulation.swipedismiss.DismissableManager} to specify which views can or cannot be swiped.
     * @param dismissableManager null for no restrictions.
     */
    @SuppressWarnings("UnusedDeclaration")
    public void setDismissableManager(final DismissableManager dismissableManager) {
        mDismissableManager = dismissableManager;
    }

    @Override
    public boolean onTouch(final View view, final 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_CANCEL:
                return handleCancelEvent(motionEvent);
            case MotionEvent.ACTION_UP:

                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(final int position, final View view) {
        return new PendingDismissData(position, view);
    }

    private boolean handleDownEvent(final MotionEvent motionEvent) {
        // 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) {
            mDownX = motionEvent.getRawX();
            mDownY = motionEvent.getRawY();
            int downPosition = AdapterViewUtil.getPositionForView(mListView, downView);

            if (mDismissableManager != null) {
                long downId = mListView.getAdapter().getItemId(downPosition);
                if (!mDismissableManager.isDismissable(downId, downPosition)) {
                    /* Cancel, not dismissable */
                    return false;
                }
            }

            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) motionEvent.getX(), (int) motionEvent.getY())) {
                            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(final 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(final MotionEvent motionEvent) {
        if (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) {
            ViewHelper.setTranslationX(mCurrentDismissData.view, deltaX);
            //noinspection MagicNumber
            ViewHelper.setAlpha(mCurrentDismissData.view, Math.max(0f, Math.min(1f, 1f - 2f * Math.abs(deltaX) / mViewWidth)));
            return true;
        }
        return false;
    }

    @SuppressWarnings("UnusedParameters")
    private boolean handleCancelEvent(final MotionEvent motionEvent) {
        if (mVelocityTracker == null) {
            return false;
        }

        if (mCurrentDismissData != null && mSwiping) {
            ViewPropertyAnimator.animate(mCurrentDismissData.view)
                    .translationX(0)
                    .alpha(1)
                    .setDuration(mAnimationTime)
                    .setListener(null);
        }
        mVelocityTracker.recycle();
        mVelocityTracker = null;
        mDownX = 0;
        mDownY = 0;
        mCurrentDismissData = null;
        mSwiping = false;
        return false;
    }


    private boolean handleUpEvent(final 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) {
                // 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(final Animator animation) {
                        onDismiss(pendingDismissData);
                    }
                });

                mVirtualListCount--;
                mPendingDismisses.add(mCurrentDismissData);
            } else {
                // cancel
                animate(mCurrentDismissData.view).translationX(0).alpha(1).setDuration(mAnimationTime).setListener(null);
            }
        }

        mVelocityTracker.recycle();
        mVelocityTracker = null;
        mDownX = 0;
        mDownY = 0;
        mCurrentDismissData = null;
        mSwiping = false;
        return false;
    }

    protected class PendingDismissData implements Comparable<PendingDismissData> {
        public final int position;
        public final View view;

        public PendingDismissData(final int position, final View view) {
            this.position = position;
            this.view = view;
        }

        @Override
        public int compareTo(final 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(final Object obj) {
            if (this == obj)
                return true;
            if (obj == null)
                return false;
            if (((Object) this).getClass() != obj.getClass())
                return false;
            PendingDismissData other = (PendingDismissData) obj;
            return position == other.position;
        }

    }

    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.

        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(final ValueAnimator valueAnimator) {
                lp.height = (Integer) valueAnimator.getAnimatedValue();
                data.view.setLayoutParams(lp);
            }
        });

        animator.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(final Animator animation) {
                finalizeDismiss();
            }
        });
        animator.start();
    }

    /**
     * Here you can manage dismissed View.
     */
    protected void recycleDismissedViewsItems(final List<PendingDismissData> pendingDismisses) {
        ViewGroup.LayoutParams lp;
        for (final 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(final boolean isParentHorizontalScrollContainer) {
        mIsParentHorizontalScrollContainer = mResIdOfTouchChild == 0 && isParentHorizontalScrollContainer;
    }

    void setTouchChild(final int childResId) {
        mResIdOfTouchChild = childResId;
        if (childResId != 0) {
            setIsParentHorizontalScrollContainer(false);
        }
    }

    public void notifyDataSetChanged() {
        mVirtualListCount = mListView.getAdapter().getCount();
    }
}