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

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >    <ImageView         android:id="@+id/imageview"        android:layout_width="wrap_content"        android:layout_height="wrap_content"       /></LinearLayout>

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

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