android背景滚动+Matrix实现图片拉伸（实现近大远小效果），,package com.

android背景滚动+Matrix实现图片拉伸（实现近大远小效果），,package com.

package com.sarnath.activity;import java.util.Timer;import java.util.TimerTask;import android.app.Activity;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Matrix;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.view.Display;import android.view.View;public class GbdemoActivity extends Activity {    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(new MyView(this));    }    class MyView extends View {        // 得到容器分辨率 高，宽        Display display = getWindowManager().getDefaultDisplay();        // 记录背景图片实际的高度        final int BACK_HEIGHT = 960;        // 背景图片        private Bitmap back;        private Bitmap plane;        private Bitmap map_01;        // 背景图片的开始位置  320 480        final int WIDTH = display.getWidth();        final int HEIGHT = display.getHeight();        private int startY = BACK_HEIGHT - HEIGHT;        public MyView(Context context) {            super(context);            // 获取背景图片            back = BitmapFactory.decodeResource(context.getResources(),                    R.drawable.map_02);            plane = BitmapFactory.decodeResource(context.getResources(),                    R.drawable.plan_1);            final Handler handler = new Handler() {                public void handleMessage(Message msg) {                    if (msg.what == 0x123) {                        // 重新开始移动                        if (startY <= 0) {                            startY = BACK_HEIGHT - HEIGHT;                        } else {                            startY -= 10;                        }                    }                    //该函数的作用是使整个窗口客户区无效。窗口的客户区无效意味着需要重绘                    invalidate();                }            };            new Timer().schedule(new TimerTask(){                @Override                public void run() {                    handler.sendEmptyMessage(0x123);                }            }, 0,100);        }        @Override        protected void onDraw(Canvas canvas) {            // 根据原始位图和Matrix创建新图片            Bitmap bitmap2 = Bitmap.createBitmap(back, 0, startY, WIDTH,HEIGHT);            //设置拉伸的比例  实现 等腰梯形            float[] src=new float[] { 0, 0, WIDTH,    0, WIDTH, HEIGHT, 0, HEIGHT };            float[] dst=new float[] { 100, 0, 200, 0, 500, 450, -150, 450 };            //获取Matrix对象 实现 图片拉伸            Matrix mMatrix=new Matrix();            mMatrix.setPolyToPoly(src, 0, dst, 0, src.length >> 1);            // 绘制新位图            canvas.drawBitmap(bitmap2, mMatrix, null);            //绘制小飞机            canvas.drawBitmap(plane, 160, 380 ,null);        }    }}//该片段来自于http://byrx.net