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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.gallery3d.ui;
     18 
     19 import android.content.Context;
     20 import android.os.SystemClock;
     21 import android.view.GestureDetector;
     22 import android.view.MotionEvent;
     23 import android.view.ScaleGestureDetector;
     24 
     25 // This class aggregates three gesture detectors: GestureDetector,
     26 // ScaleGestureDetector, and DownUpDetector.
     27 public class GestureRecognizer {
     28     private static final String TAG = "GestureRecognizer";
     29 
     30     public interface Listener {
     31         boolean onSingleTapUp(float x, float y);
     32         boolean onDoubleTap(float x, float y);
     33         boolean onScroll(float dx, float dy, float totalX, float totalY);
     34         boolean onFling(float velocityX, float velocityY);
     35         boolean onScaleBegin(float focusX, float focusY);
     36         boolean onScale(float focusX, float focusY, float scale);
     37         void onScaleEnd();
     38         void onDown(float x, float y);
     39         void onUp();
     40     }
     41 
     42     private final GestureDetector mGestureDetector;
     43     private final ScaleGestureDetector mScaleDetector;
     44     private final DownUpDetector mDownUpDetector;
     45     private final Listener mListener;
     46 
     47     public GestureRecognizer(Context context, Listener listener) {
     48         mListener = listener;
     49         mGestureDetector = new GestureDetector(context, new MyGestureListener(),
     50                 null, true /* ignoreMultitouch */);
     51         mScaleDetector = new ScaleGestureDetector(
     52                 context, new MyScaleListener());
     53         mDownUpDetector = new DownUpDetector(new MyDownUpListener());
     54     }
     55 
     56     public void onTouchEvent(MotionEvent event) {
     57         mGestureDetector.onTouchEvent(event);
     58         mScaleDetector.onTouchEvent(event);
     59         mDownUpDetector.onTouchEvent(event);
     60     }
     61 
     62     public boolean isDown() {
     63         return mDownUpDetector.isDown();
     64     }
     65 
     66     public void cancelScale() {
     67         long now = SystemClock.uptimeMillis();
     68         MotionEvent cancelEvent = MotionEvent.obtain(
     69                 now, now, MotionEvent.ACTION_CANCEL, 0, 0, 0);
     70         mScaleDetector.onTouchEvent(cancelEvent);
     71         cancelEvent.recycle();
     72     }
     73 
     74     private class MyGestureListener
     75                 extends GestureDetector.SimpleOnGestureListener {
     76         @Override
     77         public boolean onSingleTapUp(MotionEvent e) {
     78             return mListener.onSingleTapUp(e.getX(), e.getY());
     79         }
     80 
     81         @Override
     82         public boolean onDoubleTap(MotionEvent e) {
     83             return mListener.onDoubleTap(e.getX(), e.getY());
     84         }
     85 
     86         @Override
     87         public boolean onScroll(
     88                 MotionEvent e1, MotionEvent e2, float dx, float dy) {
     89             return mListener.onScroll(
     90                     dx, dy, e2.getX() - e1.getX(), e2.getY() - e1.getY());
     91         }
     92 
     93         @Override
     94         public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
     95                 float velocityY) {
     96             return mListener.onFling(velocityX, velocityY);
     97         }
     98     }
     99 
    100     private class MyScaleListener
    101             extends ScaleGestureDetector.SimpleOnScaleGestureListener {
    102         @Override
    103         public boolean onScaleBegin(ScaleGestureDetector detector) {
    104             return mListener.onScaleBegin(
    105                     detector.getFocusX(), detector.getFocusY());
    106         }
    107 
    108         @Override
    109         public boolean onScale(ScaleGestureDetector detector) {
    110             return mListener.onScale(detector.getFocusX(),
    111                     detector.getFocusY(), detector.getScaleFactor());
    112         }
    113 
    114         @Override
    115         public void onScaleEnd(ScaleGestureDetector detector) {
    116             mListener.onScaleEnd();
    117         }
    118     }
    119 
    120     private class MyDownUpListener implements DownUpDetector.DownUpListener {
    121         @Override
    122         public void onDown(MotionEvent e) {
    123             mListener.onDown(e.getX(), e.getY());
    124         }
    125 
    126         @Override
    127         public void onUp(MotionEvent e) {
    128             mListener.onUp();
    129         }
    130     }
    131 }
    132