<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:id="@+id/relativeLayout1"     android:layout_width="fill_parent"     android:layout_height="fill_parent" >     <Button         android:id="@+id/zoom_in"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignParentLeft="true"         android:layout_alignParentTop="true"         android:text="zoom_in" />     <Button         android:id="@+id/zoom_out"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignParentRight="true"         android:layout_alignParentTop="true"         android:text="zoom_out" />     <ScrollView         android:id="@+id/imageContainer"         android:layout_width="fill_parent"         android:layout_height="fill_parent"         android:layout_below="@+id/zoom_in"         android:fadingEdge="none"         android:scrollbars="none" >         <HorizontalScrollView             android:layout_width="fill_parent"             android:layout_height="fill_parent"             android:layout_centerHorizontal="true"             android:fadingEdge="none"             android:scrollbars="none" >             <ImageView                 android:id="@+id/imageView"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"                 android:layout_alignParentTop="true"                 android:layout_centerHorizontal="true"                 android:scaleType="matrix" />         </HorizontalScrollView>     </ScrollView> </RelativeLayout>

package taokun.demo.MutilTouchDemo; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Matrix; import android.graphics.PointF; import android.os.Bundle; import android.util.FloatMath; import android.util.Log; import android.view.MotionEvent; import android.view.View; import android.view.View.OnClickListener; import android.view.View.OnTouchListener; import android.widget.Button; import android.widget.ImageView; public class MutilTouchDemoActivity extends Activity implements OnTouchListener, OnClickListener {    private static final String TAG = "Touch" ;    // These matrices will be used to move and zoom image    Matrix matrix = new Matrix();    Matrix savedMatrix = new Matrix();    PointF start = new PointF();    PointF mid = new PointF();    float  oldDist;    private ImageView view;    private Button zoomIn, zoomOut;    //button zoom    private float scaleWidth = 1;         private float scaleHeight = 1;         private Bitmap bmp, zoomedBMP;         private int zoom_level = 0;         private static final double ZOOM_IN_SCALE = 1.25;//放大系数         private static final double ZOOM_OUT_SCALE = 0.8;//缩小系数    // We can be in one of these 3 states    static final int NONE = 0;    static final int DRAG = 1;    static final int ZOOM = 2;    int mode = NONE;    @Override    public void onCreate(Bundle savedInstanceState) {       super.onCreate(savedInstanceState);       setContentView(R.layout.main);       //放大按钮       zoomIn = (Button) findViewById(R.id.zoom_in);        //缩小按钮       zoomOut = (Button) findViewById(R.id.zoom_out);       zoomIn.setOnClickListener(this);       zoomOut.setOnClickListener(this);       view = (ImageView) findViewById(R.id.imageView);       view.setOnTouchListener(this);       //取得drawable中图片，放大，缩小，多点触摸的作用对象            bmp = BitmapFactory.decodeResource(MutilTouchDemoActivity.this.getResources(), R.drawable.splash);               }    public boolean onTouch(View v, MotionEvent event) {       // Handle touch events here...       ImageView view = (ImageView) v;       // Handle touch events here...       switch (event.getAction() & MotionEvent.ACTION_MASK) {         //设置拖拉模式         case MotionEvent.ACTION_DOWN:             savedMatrix.set(matrix);             start.set(event.getX(), event.getY());             Log.d(TAG, "mode=DRAG" );             mode = DRAG;             break;          case MotionEvent.ACTION_UP:          case MotionEvent.ACTION_POINTER_UP:             mode = NONE;             Log.d(TAG, "mode=NONE" );             break;          //设置多点触摸模式          case MotionEvent.ACTION_POINTER_DOWN:             oldDist = spacing(event);             Log.d(TAG, "oldDist=" + oldDist);             if (oldDist > 10f) {                savedMatrix.set(matrix);                midPoint(mid, event);                mode = ZOOM;                Log.d(TAG, "mode=ZOOM" );             }             break;           //若为DRAG模式，则点击移动图片          case MotionEvent.ACTION_MOVE:             if (mode == DRAG) {                matrix.set(savedMatrix);                // 设置位移                matrix.postTranslate(event.getX() - start.x,               event.getX() - start.x);             }             //若为ZOOM模式，则多点触摸缩放                else if (mode == ZOOM) {                float newDist = spacing(event);                Log.d(TAG, "newDist=" + newDist);                if (newDist > 10f) {                   matrix.set(savedMatrix);                   float scale = newDist / oldDist;                   //设置缩放比例和图片中点位置                   matrix.postScale(scale, scale, mid.x, mid.y);                }             }             break;       }       // Perform the transformation       view.setImageMatrix(matrix);       return true; // indicate event was handled    } //计算移动距离    private float spacing(MotionEvent event) {       float x = event.getX(0) - event.getX(1);       float y = event.getY(0) - event.getY(1);       return FloatMath.sqrt(x * x + y * y);    } // 计算中点位置    private void midPoint(PointF point, MotionEvent event) {       float x = event.getX(0) + event.getX(1);       float y = event.getY(0) + event.getY(1);       point.set(x / 2, y / 2);    } //放大，缩小按钮点击事件 @Override public void onClick(View v) {         if(v == zoomIn){                 enlarge();         }else if (v == zoomOut) {                 small();         } } //按钮点击缩小函数 private void small() {         int bmpWidth = bmp.getWidth();         int bmpHeight = bmp.getHeight();         scaleWidth = (float) (scaleWidth * ZOOM_OUT_SCALE);         scaleHeight = (float) (scaleHeight * ZOOM_OUT_SCALE);         Matrix matrix = new Matrix();         matrix.postScale(scaleWidth, scaleHeight);         zoomedBMP = Bitmap.createBitmap(bmp, 0, 0, bmpWidth, bmpHeight, matrix,                         true);         view.setImageBitmap(zoomedBMP); } //按钮点击放大函数 private void enlarge() {         try {                 int bmpWidth = bmp.getWidth();                 int bmpHeight = bmp.getHeight();                 scaleWidth = (float) (scaleWidth * ZOOM_IN_SCALE);                 scaleHeight = (float) (scaleHeight * ZOOM_IN_SCALE);                 Matrix matrix = new Matrix();                 matrix.postScale(scaleWidth, scaleHeight);                 zoomedBMP = Bitmap.createBitmap(bmp, 0, 0, bmpWidth, bmpHeight, matrix,                                 true);                 view.setImageBitmap(zoomedBMP);         } catch (Exception e) {         } } }