public class ex04_22 extends Activity{private ImageView mImageView;private Button btn1,btn2;private TextView mTextView;private AbsoluteLayout layout1;private Bitmap bmp;private int id=0;private int displayWidth,displayHeight;private float scaleWidth=1,scaleHeight=1;private final static String filename="/data/data/ex04_22.lcs/ex04_22_2.png";@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);//取得屏幕分辨率DisplayMetrics dm=new DisplayMetrics();getWindowManager().getDefaultDisplay().getMetrics(dm);displayWidth=dm.widthPixels;displayHeight=dm.heightPixels-80;bmp=BitmapFactory.decodeResource(this.getResources(),R.drawable.ex04_22_1);layout1=(AbsoluteLayout)findViewById(R.id.layout1);mImageView=(ImageView)findViewById(R.id.myImageView);btn1=(Button)findViewById(R.id.myButton1);btn1.setOnClickListener(new OnClickListener(){public void onClick(View v){small();}});btn2=(Button)findViewById(R.id.myButton2);btn2.setOnClickListener(new OnClickListener(){public void onClick(View v){big();}});}private void small(){//获得Bitmap的高和宽int bmpWidth=bmp.getWidth();int bmpHeight=bmp.getHeight();//设置缩小比例double scale=0.8;//计算出这次要缩小的比例scaleWidth=(float)(scaleWidth*scale);scaleHeight=(float)(scaleHeight*scale);//产生resize后的Bitmap对象Matrix matrix=new Matrix();matrix.postScale(scaleWidth, scaleHeight);Bitmap resizeBmp=Bitmap.createBitmap(bmp, 0, 0, bmpWidth, bmpHeight, matrix, true);if(id==0){layout1.removeView(mImageView);}else{layout1.removeView((ImageView)findViewById(id));}id++;ImageView imageView=new ImageView(this);imageView.setId(id);imageView.setImageBitmap(resizeBmp);layout1.addView(imageView);setContentView(layout1);btn2.setEnabled(true);}private void big(){//获得Bitmap的高和宽int bmpWidth=bmp.getWidth();int bmpHeight=bmp.getHeight();//设置缩小比例double scale=1.25;//计算出这次要缩小的比例scaleWidth=(float)(scaleWidth*scale);scaleHeight=(float)(scaleHeight*scale);//产生resize后的Bitmap对象Matrix matrix=new Matrix();matrix.postScale(scaleWidth, scaleHeight);Bitmap resizeBmp=Bitmap.createBitmap(bmp, 0, 0, bmpWidth, bmpHeight, matrix, true);if(id==0){layout1.removeView(mImageView);}else{layout1.removeView((ImageView)findViewById(id));}id++;ImageView imageView=new ImageView(this);imageView.setId(id);imageView.setImageBitmap(resizeBmp);layout1.addView(imageView);setContentView(layout1);if(scaleWidth*scale*bmpWidth>displayWidth||scaleHeight*scale*scaleHeight>displayHeight){btn2.setEnabled(false);}}
}
xml文件
<?xml version="1.0" encoding="utf-8"?>
<AbsoluteLayoutandroid:id="@+id/layout1"android:layout_width="fill_parent"android:layout_height="fill_parent"xmlns:android="http://schemas.android.com/apk/res/android"><ImageViewandroid:id="@+id/myImageView"android:layout_width="200px"android:layout_height="150px"android:src="@drawable/ex04_22_1"android:layout_x="0px"android:layout_y="0px"></ImageView><Buttonandroid:id="@+id/myButton1"android:layout_width="90px"android:layout_height="60px"android:text="缩小"android:textSize="18sp"android:layout_x="20px"android:layout_y="372px"></Button><Buttonandroid:id="@+id/myButton2"android:layout_width="90px"android:layout_height="60px"android:text="放大"android:textSize="18sp"android:layout_x="210px"android:layout_y="372px"></Button></AbsoluteLayout>