Android Open Source - ImageCropper Touch Event Detector

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License

The source code is released under:

Apache License

Java Source Code

/*
 *  COPYRIGHT NOTICE  //from   w w  w.  ja va  2  s .  c o m
 *  Copyright (C) 2015, ticktick <lujun.hust@gmail.com>
 *  http://ticktick.blog.51cto.com/
 *   
 *  @license under the Apache License, Version 2.0 
 *
 *  @file    TouchEventDetector.java
 *  @brief   Detect the touch event
 *  
 *  @version 1.0     
 *  @author  ticktick
 *  @date    2015/01/09    
 */
package com.ticktick.imagecropper;

import android.graphics.PointF;
import android.view.MotionEvent;

public class TouchEventDetector {

    private static final float DETECT_THRESHOLD = (float)0.05;

    private PointF mPoint = new PointF(0,0);  
    private TouchEventListener mTouchEventListener;
    private boolean mIsDetectStarted = false;

    public interface TouchEventListener {
  public void onTouchDown( float x, float y );
  public void onTouchUp( float x, float y );
  public void onTouchMoved( float srcX, float srcY, float deltaX, float deltaY );    
    }

    public void setTouchEventListener( TouchEventListener listener ) {
  mTouchEventListener = listener;
    }
  
    public boolean onTouchEvent( MotionEvent event ) {
  
  if( mTouchEventListener == null || event.getPointerCount() != 1 ) {
            mIsDetectStarted = false;
            return false;
  }
  
  int action = event.getAction() & MotionEvent.ACTION_MASK;
  if( action == MotionEvent.ACTION_DOWN ) {      
            mTouchEventListener.onTouchDown(event.getX(), event.getY());
            mIsDetectStarted = true;
  }    
  else if( action == MotionEvent.ACTION_UP ) {            
            mTouchEventListener.onTouchUp(event.getX(), event.getY());
            mIsDetectStarted = false;
  }
  else if( mIsDetectStarted && action == MotionEvent.ACTION_MOVE ) {      
            if( Math.abs(mPoint.x - event.getX()) > DETECT_THRESHOLD || Math.abs(mPoint.y-event.getY()) > DETECT_THRESHOLD ) {        
    mTouchEventListener.onTouchMoved(mPoint.x, mPoint.y, event.getX()-mPoint.x,event.getY()-mPoint.y);
      }                
  }    

  mPoint.set(event.getX(),event.getY());
  
  return true;    
    }
}

Java Source Code List

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