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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     @SuppressWarnings("unused")
     29     private static final String TAG = "GestureRecognizer";
     30 
     31     public interface Listener {
     32         boolean onSingleTapUp(float x, float y);
     33         boolean onDoubleTap(float x, float y);
     34         boolean onScroll(float dx, float dy, float totalX, float totalY);
     35         boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY);
     36         boolean onScaleBegin(float focusX, float focusY);
     37         boolean onScale(float focusX, float focusY, float scale);
     38         void onScaleEnd();
     39         void onDown(float x, float y);
     40         void onUp();
     41     }
     42 
     43     private final GestureDetector mGestureDetector;
     44     private final ScaleGestureDetector mScaleDetector;
     45     private final DownUpDetector mDownUpDetector;
     46     private final Listener mListener;
     47 
     48     public GestureRecognizer(Context context, Listener listener) {
     49         mListener = listener;
     50         mGestureDetector = new GestureDetector(context, new MyGestureListener(),
     51                 null, true /* ignoreMultitouch */);
     52         mScaleDetector = new ScaleGestureDetector(
     53                 context, new MyScaleListener());
     54         mDownUpDetector = new DownUpDetector(new MyDownUpListener());
     55     }
     56 
     57     public void onTouchEvent(MotionEvent event) {
     58         mGestureDetector.onTouchEvent(event);
     59         mScaleDetector.onTouchEvent(event);
     60         mDownUpDetector.onTouchEvent(event);
     61     }
     62 
     63     public boolean isDown() {
     64         return mDownUpDetector.isDown();
     65     }
     66 
     67     public void cancelScale() {
     68         long now = SystemClock.uptimeMillis();
     69         MotionEvent cancelEvent = MotionEvent.obtain(
     70                 now, now, MotionEvent.ACTION_CANCEL, 0, 0, 0);
     71         mScaleDetector.onTouchEvent(cancelEvent);
     72         cancelEvent.recycle();
     73     }
     74 
     75     private class MyGestureListener
     76                 extends GestureDetector.SimpleOnGestureListener {
     77         @Override
     78         public boolean onSingleTapUp(MotionEvent e) {
     79             return mListener.onSingleTapUp(e.getX(), e.getY());
     80         }
     81 
     82         @Override
     83         public boolean onDoubleTap(MotionEvent e) {
     84             return mListener.onDoubleTap(e.getX(), e.getY());
     85         }
     86 
     87         @Override
     88         public boolean onScroll(
     89                 MotionEvent e1, MotionEvent e2, float dx, float dy) {
     90             return mListener.onScroll(
     91                     dx, dy, e2.getX() - e1.getX(), e2.getY() - e1.getY());
     92         }
     93 
     94         @Override
     95         public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
     96                 float velocityY) {
     97             return mListener.onFling(e1, e2, velocityX, velocityY);
     98         }
     99     }
    100 
    101     private class MyScaleListener
    102             extends ScaleGestureDetector.SimpleOnScaleGestureListener {
    103         @Override
    104         public boolean onScaleBegin(ScaleGestureDetector detector) {
    105             return mListener.onScaleBegin(
    106                     detector.getFocusX(), detector.getFocusY());
    107         }
    108 
    109         @Override
    110         public boolean onScale(ScaleGestureDetector detector) {
    111             return mListener.onScale(detector.getFocusX(),
    112                     detector.getFocusY(), detector.getScaleFactor());
    113         }
    114 
    115         @Override
    116         public void onScaleEnd(ScaleGestureDetector detector) {
    117             mListener.onScaleEnd();
    118         }
    119     }
    120 
    121     private class MyDownUpListener implements DownUpDetector.DownUpListener {
    122         @Override
    123         public void onDown(MotionEvent e) {
    124             mListener.onDown(e.getX(), e.getY());
    125         }
    126 
    127         @Override
    128         public void onUp(MotionEvent e) {
    129             mListener.onUp();
    130         }
    131     }
    132 }
    133