1.Activity

package com.fit.touchimage;

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.view.MotionEvent;

import android.view.View;

import android.view.View.OnTouchListener;

import android.view.ViewGroup.MarginLayoutParams;

import android.widget.ImageView;

public class MainActivity extends Activity implements OnTouchListener {

    /** Called when the activity is first created. */

 

 //放大缩小

 Matrix matrix=new Matrix();

 Matrix savedMatrix=new Matrix();

 

 PointF start=new PointF();

 PointF mid=new PointF();

 float oldDist;

 

 private ImageView myImageView;

 

 //模式

 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);

       

        myImageView=(ImageView) findViewById(R.id.myImage);

        myImageView.setOnTouchListener(this);

       

    }

 @Override

 public boolean onTouch(View v, MotionEvent event) {

  ImageView myImageView=(ImageView) v;

  switch(event.getAction()&MotionEvent.ACTION_MASK){

   //设置拖拉模式

  case MotionEvent.ACTION_DOWN:

   matrix.set(myImageView.getImageMatrix());

   savedMatrix.set(matrix);

   start.set(event.getX(),event.getY());

   mode=DRAG;

  break;

  case MotionEvent.ACTION_UP:

  case MotionEvent.ACTION_POINTER_UP:

   mode=NONE;

   break;

  

  //设置多点触摸模式

  case MotionEvent.ACTION_POINTER_DOWN:

   oldDist=spacing(event);

   if(oldDist>10f){

    savedMatrix.set(matrix);

    midPoint(mid, event);

    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);

    matrix.postTranslate(event.getX()-start.x,event.getY()-start.y);

   }

   //若为ZOOM模式，则点击触摸缩放

   else if(mode==ZOOM){

    float newDist=spacing(event);

    if(newDist>10f){

     matrix.set(savedMatrix);

     float scale=newDist/oldDist;

     //设置硕放比例和图片的中点位置

     matrix.postScale(scale,scale, mid.x,mid.y);

    }

   }

   break;

  } 

  myImageView.setImageMatrix(matrix);

  return true;

 }

 //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);

 }

}

 

2.布局

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

<LinearLayout xmlns:android=""

 android:orientation="vertical" android:layout_width="fill_parent"

 android:layout_height="fill_parent" android:gravity="center">

 <ImageView android:layout_width="fill_parent"

  android:layout_height="fill_parent" android:scaleType="matrix"

  android:id="@+id/myImage" android:src="@drawable/xiaoxiong"/>

</LinearLayout>