Android ZoomControls放大缩小图片

ZoomControls控件是一个可以缩放但控件，效果如下图以下是它但一些主要但方法

       hasFocus ()：判断焦点
       hide ()：隐藏
       onTouchEvent (MotionEvent event)：现这个方法来处理触摸屏移动事件
       setIsZoomInEnabled (boolean isEnabled)：是否允许放大
       setIsZoomOutEnabled (boolean isEnabled)：是否允许缩小
       setOnZoomInClickListener (View.OnClickListener listener)：注册放大监听器
       setOnZoomOutClickListener (View.OnClickListener listener)：注册缩小监听器
       setZoomSpeed (long speed)：设置缩放速度

       show ()：显示

资源文件如下

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:id="@+id/layout1"

>

<ImageView

android:id="@+id/imgview"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:src="@drawable/yuanyuan"

/>

<ZoomControls

android:id="@+id/zoomcontrol"

android:layout_gravity="bottom"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

/>

</LinearLayout>

代码文件

  package  zoomcontroltest;


    import android.app.Activity;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.graphics.Matrix;
    import android.os.Bundle;
    import android.util.DisplayMetrics;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.ImageView;
    import android.widget.LinearLayout;
    import android.widget.ZoomControls;


    public class ZoomExampleActivity extends Activity {
    private LinearLayout layout1;
    private ZoomControls zoom;
    private ImageView img;
    private int id=0;
    private int displayWidth;
    private int displayHeight;
    private float scaleWidth = 1;
    private float scaleHeight = 1;
    private Bitmap bmp;


    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    layout1 = (LinearLayout)findViewById(R.id.layout1);
    //取得屏幕分辨率大小
    DisplayMetrics dm = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(dm);
    displayWidth = dm.widthPixels;
    //屏幕高度减去zoomControls的高度
    displayHeight = dm.heightPixels;
    bmp = BitmapFactory.decodeResource(getResources(), R.drawable.yuanyuan);
    img = (ImageView)findViewById(R.id.imgview);
    //zoom.hide();隐藏zoomControls
    //zoom.show();显示zoomCOntrols
    zoom = (ZoomControls)findViewById(R.id.zoomcontrol);
    img = (ImageView)findViewById(R.id.imgview);
    zoom.setIsZoomInEnabled(true);
    zoom.setIsZoomOutEnabled(true);
    //图片放大
    zoom.setOnZoomInClickListener(new OnClickListener()
    {
    public void onClick(View v)
    {
    int bmpWidth = bmp.getWidth();
    int bmpHeight = bmp.getHeight();
    //设置图片放大但比例
    double scale = 1.25;
    //计算这次要放大的比例
    scaleWidth = (float)(scaleWidth*scale);
    scaleHeight = (float)(scaleHeight*scale);
    //产生新的大小但Bitmap对象
    Matrix matrix = new Matrix();
    matrix.postScale(scaleWidth, scaleHeight);
    Bitmap resizeBmp = Bitmap.createBitmap(bmp,0,0,bmpWidth,bmpHeight,matrix,true);
    img.setImageBitmap(resizeBmp);
    }
    });
    //图片减小
    zoom.setOnZoomOutClickListener(new OnClickListener()
    {

    public void onClick(View v) {
    int bmpWidth = bmp.getWidth();
    int bmpHeight = bmp.getHeight();
    //设置图片放大但比例
    double scale = 0.8;
    //计算这次要放大的比例
    scaleWidth = (float)(scaleWidth*scale);
    scaleHeight = (float)(scaleHeight*scale);
    //产生新的大小但Bitmap对象
    Matrix matrix = new Matrix();
    matrix.postScale(scaleWidth, scaleHeight);
    Bitmap resizeBmp = Bitmap.createBitmap(bmp,0,0,bmpWidth,bmpHeight,matrix,true);
    img.setImageBitmap(resizeBmp);
    }
    });
    }
    }