android 双击图片放大，再双击缩小效果 【安卓进化九】

今天写了个onDoubleTap事件的处理方法，双击屏幕事件的放大缩小的程序，双击屏幕图片放大，再双击屏幕图片缩小到原来的效果。请看截图的效果！

原图： 双击屏幕放大后的效果：

现把代码贴出来：

一、MainActivty.java类中的代码：

package com.cn.android;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.GestureDetector.OnGestureListener;

public class mainActivity extends Activity implements OnGestureListener{
   
    private ImageShowView mImageShowView = null;
    private GestureDetector gestureScanner;
    private double Scale = 1.0;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        mImageShowView = new ImageShowView(this);
        setContentView(mImageShowView);
           
        gestureScanner = new GestureDetector(this);   
        gestureScanner.setOnDoubleTapListener(new GestureDetector.OnDoubleTapListener(){

            @Override
            public boolean onDoubleTap(MotionEvent e) {
                // TODO Auto-generated method stub
                // 双击时产生一次                    
                if(Scale == 1.0){
                    Scale = Scale + 0.5;
                    mImageShowView.setScale(Scale);
                }
                else if(Scale == 1.5){
                    Scale = Scale - 0.5;
                    mImageShowView.setScale(Scale);
                }
                Log.v("daming", "onDoubleTap");
                return true;
            }

            @Override
            public boolean onDoubleTapEvent(MotionEvent e) {
                // TODO Auto-generated method stub
                // 双击时产生两次
                Log.v("daming", "onDoubleTapEvent");
                return false;
            }

            @Override
            public boolean onSingleTapConfirmed(MotionEvent e) {
                //短快的点击算一次单击
                Log.v("daming", "onSingleTapConfirmed");
                return false;  
            }     
        });
    }
    
    @Override  
    public boolean onTouchEvent(MotionEvent me) {   
      return gestureScanner.onTouchEvent(me);   
    }

    @Override
    public boolean onDown(MotionEvent e) {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
            float velocityY) {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public void onLongPress(MotionEvent e) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
            float distanceY) {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public void onShowPress(MotionEvent e) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        // TODO Auto-generated method stub
        return false;
    }   
  

}

二、ImageShowView.java中的代码：

package com.cn.android;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.view.KeyEvent;
import android.view.View;

public class ImageShowView extends View implements Runnable{

    Bitmap mBitmap = null;
    int mBitmapWidth = 0;//定义图片的宽
    int mBitmapHeight = 0;//定义图片的高
    
    private double Scale = 1.0;
    
    Matrix mMatrix = new Matrix();
    
    public ImageShowView(Context context) {
        super(context);
        
        mBitmap = ((BitmapDrawable)getResources().getDrawable(R.drawable.image1)).getBitmap();
        
        mBitmapWidth = mBitmap.getWidth();
        mBitmapHeight = mBitmap.getHeight();
        
        //开启线程
        new Thread(this).start();
    }

    public void setScale(double scale){
         this.Scale = scale;
    }
    
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        mMatrix.reset();
        mMatrix.postScale((float)Scale, (float)Scale);//设置缩放
        
        Bitmap mBitmap2 = Bitmap.createBitmap(mBitmap,0,0,mBitmapWidth,mBitmapHeight,mMatrix,true);
        
        //绘制旋转之后的图像
        ImageShowView.drawImage(canvas,mBitmap2,(320-mBitmapWidth)/2,10);
        mBitmap2 = null;
    }

    @Override
    public void run() {
        
        while(!Thread.currentThread().isInterrupted()){
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            postInvalidate();
        }    
    }
    
    private static void drawImage(Canvas canvas, Bitmap bitmap, int x, int y) {
        // TODO Auto-generated method stub
        canvas.drawBitmap(bitmap, x, y, null);
    }
}

说明：以上就是我的全部代码，项目中的图片就不上传了，大家可以自己传个图片上去就可以了，有需要完整代码的可以留邮箱，大家有任何问题，可以给我留言，我看到就回复！大家有好的意见可以提出来，共同学习，共同进步！