图片随着手指动

MainActivity：

package com.example.day2_one;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.RelativeLayout.LayoutParams;

public class MainActivity extends Activity {

    private ImageView image_view;
    float lastDistance = -1;
    float x0 = 0;
    float y0 = 0;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        image_view=(ImageView) findViewById(R.id.image_view);
        image_view.setOnTouchListener(new OnTouchListener() {

            @Override
            public boolean onTouch(View v, MotionEvent event) {
                // TODO Auto-generated method stub
                int action=event.getAction();
                switch (action) {
                //触摸开始
                case MotionEvent.ACTION_UP:
                    image_view.setX(event.getX());
                    image_view.setY(event.getY());

                    break;
                case MotionEvent.ACTION_MOVE:
                    //得到触摸点的个数
                    int count=event.getPointerCount();
                    if(count>1){
                    //获得亮点的坐标差
                        float distanceX=event.getX(0)-event.getX(1);
                        float distanceY=event.getY(0)-event.getY(1);
                        //获得来那个两点之间的距离
                        float between=(float) Math.sqrt(distanceX*distanceY+distanceX*distanceY);
                        if(between<1){
                            lastDistance=between;
                        }else if((between-lastDistance)>5){
                            //放大
                            lastDistance=between;
                            //获得布局参数
                            RelativeLayout.LayoutParams parmars=(LayoutParams) image_view.getLayoutParams();
                            parmars.width=(int) (image_view.getWidth()*1.1f);
                            parmars.height=(int) (image_view.getHeight()*1.1f);
                            image_view.setLayoutParams(parmars);

                        }else if((lastDistance-between)>5){
                            lastDistance=between;
                            //获得布局参数
                            RelativeLayout.LayoutParams params=(LayoutParams) image_view.getLayoutParams();
                            params.width=(int) (image_view.getWidth()*0.9f);
                            params.height=(int) (image_view.getHeight()*0.9f);
                            image_view.setLayoutParams(params);

                        }

                    }else if(count==1){
                        image_view.setX(event.getX());
                        image_view.setY(event.getY());
                    }
                    break;

                default:
                    break;
                }

                return true;
            }
        });
    }

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // TODO Auto-generated method stub
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;

}

}

布局：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <ImageView
        android:id="@+id/image_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
       android:src="@drawable/ic_launcher" />

</RelativeLayout>

menu文件：activity_main:

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

    <item
        android:id="@+id/menu_settings"
        android:orderInCategory="100"
        android:showAsAction="never"
        android:title="@string/menu_settings"/>

</menu>