/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.launcher3.util;
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import android.graphics.Rect;
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import android.graphics.RectF;
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import android.view.MotionEvent;
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import android.view.TouchDelegate;
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import android.view.View;
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/**
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* This class differs from the framework {@link TouchDelegate} in that it transforms the
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* coordinates of the motion event to the provided bounds.
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*
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* You can also modify the bounds post construction. Since the bounds are available during layout,
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* this avoids new object creation during every layout.
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*/
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public class TransformingTouchDelegate extends TouchDelegate {
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private static final Rect sTempRect = new Rect();
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private final RectF mBounds;
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private final RectF mTouchCheckBounds;
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private float mTouchExtension;
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private boolean mWasTouchOutsideBounds;
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private View mDelegateView;
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private boolean mDelegateTargeted;
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public TransformingTouchDelegate(View delegateView) {
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super(sTempRect, delegateView);
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mDelegateView = delegateView;
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mBounds = new RectF();
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mTouchCheckBounds = new RectF();
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}
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public void setBounds(int left, int top, int right, int bottom) {
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mBounds.set(left, top, right, bottom);
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updateTouchBounds();
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}
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public void extendTouchBounds(float extension) {
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mTouchExtension = extension;
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updateTouchBounds();
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}
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private void updateTouchBounds() {
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mTouchCheckBounds.set(mBounds);
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mTouchCheckBounds.inset(-mTouchExtension, -mTouchExtension);
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}
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public void setDelegateView(View view) {
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mDelegateView = view;
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}
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/**
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* Will forward touch events to the delegate view if the event is within the bounds
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* specified in the constructor.
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*
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* @param event The touch event to forward
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* @return True if the event was forwarded to the delegate, false otherwise.
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*/
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public boolean onTouchEvent(MotionEvent event) {
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boolean sendToDelegate = false;
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switch (event.getAction()) {
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case MotionEvent.ACTION_DOWN:
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mDelegateTargeted = mTouchCheckBounds.contains(event.getX(), event.getY());
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if (mDelegateTargeted) {
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mWasTouchOutsideBounds = !mBounds.contains(event.getX(), event.getY());
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sendToDelegate = true;
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}
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break;
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case MotionEvent.ACTION_MOVE:
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sendToDelegate = mDelegateTargeted;
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break;
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case MotionEvent.ACTION_UP:
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case MotionEvent.ACTION_CANCEL:
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sendToDelegate = mDelegateTargeted;
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mDelegateTargeted = false;
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break;
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}
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boolean handled = false;
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if (sendToDelegate) {
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float x = event.getX();
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float y = event.getY();
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if (mWasTouchOutsideBounds) {
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event.setLocation(mBounds.centerX(), mBounds.centerY());
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} else {
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event.offsetLocation(-mBounds.left, -mBounds.top);
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}
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handled = mDelegateView.dispatchTouchEvent(event);
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event.setLocation(x, y);
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}
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return handled;
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}
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}
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