android拖动图片移动效果

java代码
Java代码
package com.twy.test;

import android.app.Activity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;

public class TestDemo extends Activity {
    private ImageView img1;
    private ImageView img2;
    private int screenWidth;
    private int screenHeight;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        img1 = (ImageView) findViewById(R.id.imageView1);
        img2 = (ImageView) findViewById(R.id.imageView2);

        DisplayMetrics dm = getResources().getDisplayMetrics();
        screenWidth = dm.widthPixels;
        screenHeight = dm.heightPixels - 50;

        img1.setOnTouchListener(movingEventListener);
        img2.setOnTouchListener(movingEventListener);

    }

    private OnTouchListener movingEventListener = new OnTouchListener() {
        int lastX, lastY;

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                lastX = (int) event.getRawX();
                lastY = (int) event.getRawY();
                break;
            case MotionEvent.ACTION_MOVE:
                int dx = (int) event.getRawX() - lastX;
                int dy = (int) event.getRawY() - lastY;

                int left = v.getLeft() + dx;
                int top = v.getTop() + dy;
                int right = v.getRight() + dx;
                int bottom = v.getBottom() + dy;
                // 设置不能出界
                if (left < 0) {
                    left = 0;
                    right = left + v.getWidth();
                }

                if (right > screenWidth) {
                    right = screenWidth;
                    left = right - v.getWidth();
                }

                if (top < 0) {
                    top = 0;
                    bottom = top + v.getHeight();
                }

                if (bottom > screenHeight) {
                    bottom = screenHeight;
                    top = bottom - v.getHeight();
                }

                v.layout(left, top, right, bottom);

                lastX = (int) event.getRawX();
                lastY = (int) event.getRawY();

                break;
            case MotionEvent.ACTION_UP:
                break;
            }
            return true;
        }
    };
}

xml 代码
Java代码
<?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">
    <RelativeLayout android:id="@+id/relativeLayout1"
        android:layout_width="fill_parent" android:layout_height="fill_parent">
        <ImageView android:id="@+id/imageView1"

补充：移动开发 , Android ,