android 图片点击一下就放大到全屏,再点一下就回到原界面

1、MainActivity.java

package com.example.imagetofullscreen;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.util.DisplayMetrics;
import android.view.Display;
import android.view.MotionEvent;
import android.widget.ImageView;

/*android 图片点击一下就放大到全屏,再点一下就回到原界面 */
public class MainActivity extends Activity {

	 
    /** Called when the activity is first created. */  
    Bitmap bp=null;  
    ImageView imageview;  
    float scaleWidth;  
    float scaleHeight;  
      
    int h;  
    boolean num=false;  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

  DisplayMetrics dm=new DisplayMetrics();//创建矩阵  
  getWindowManager().getDefaultDisplay().getMetrics(dm);
  
    imageview=(ImageView)findViewById(R.id.imageview);  
    bp=BitmapFactory.decodeResource(getResources(),R.drawable.xiaoyua);  
    int width=bp.getWidth();  
    int height=bp.getHeight();  
    int w=dm.widthPixels; //得到屏幕的宽度 
    int h=dm.heightPixels; //得到屏幕的高度
    scaleWidth=((float)w)/width;  
    scaleHeight=((float)h)/height;  
    imageview.setImageBitmap(bp);  
}  
    @Override  
    public boolean onTouchEvent(MotionEvent event) {  
              
           switch(event.getAction()){  
              
           case MotionEvent.ACTION_DOWN:  //当屏幕检测到第一个触点按下之后就会触发到这个事件。
            if(num==true)        {  
                    Matrix matrix=new Matrix();  
                    matrix.postScale(scaleWidth,scaleHeight);  
                      
                   Bitmap newBitmap=Bitmap.createBitmap(bp, 0, 0, bp.getWidth(), bp.getHeight(), matrix, true);  
                    imageview.setImageBitmap(newBitmap);  
                    num=false;  
                    }  
            else{  
                    Matrix matrix=new Matrix();  
                    matrix.postScale(1.0f,1.0f);  
                    Bitmap newBitmap=Bitmap.createBitmap(bp, 0, 0, bp.getWidth(), bp.getHeight(), matrix, true);  
                imageview.setImageBitmap(newBitmap);  
                num=true;  
            }  
                    break;  
            }  
              
             
           return super.onTouchEvent(event);  
    }       
}

2、activity_main.xml

实例代码下载： http://download.csdn.net/detail/baidu_28479651/9187679