知识点：

1 使用Service服务后台运行Toast显示小火箭

2 使用子线程更新火箭发射功能

3 使用handle.post在主线程中充当延时函数

1 使用Service服务后台运行Toast显示小火箭

1建立一个Service类，并在AndroidManifest.xml中进行注册：

public class RocketService extends Service

<service android:name=".RocketService"            ></service>

2使用WindowManager设置界面显示参数：

private void InitRocket() {mWM = (WindowManager) this.getSystemService(Context.WINDOW_SERVICE);winWidth = mWM.getDefaultDisplay().getWidth();winHeight = mWM.getDefaultDisplay().getHeight();params = new WindowManager.LayoutParams();params.height = WindowManager.LayoutParams.WRAP_CONTENT;params.width = WindowManager.LayoutParams.WRAP_CONTENT;params.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON;params.format = PixelFormat.TRANSLUCENT;params.type = WindowManager.LayoutParams.TYPE_PHONE; // 需要将类型改为TYPE_PHONE才能移动params.gravity = Gravity.LEFT + Gravity.TOP;params.setTitle("Toast");view_toastrocket = View.inflate(RocketService.this, R.layout.rocket_toast, null);ivRocket = (ImageView) view_toastrocket.findViewById(R.id.iv_rocket);// 添加view对象mWM.addView(view_toastrocket, params);view_toastrocket.setOnTouchListener(new OnTouchListener() {private int startx;private int starty;@Overridepublic boolean onTouch(View v, MotionEvent event) {switch (event.getAction()) {case MotionEvent.ACTION_DOWN:startx = (int) event.getRawX();starty = (int) event.getRawY();System.out.println("点击图片");break;case MotionEvent.ACTION_MOVE:int endx = (int) event.getRawX();int endy = (int) event.getRawY();int dx = endx - startx;int dy = endy - starty;params.x += dx;params.y += dy;if (params.x < 0) {params.x = 0;}if (params.y < 0) {params.y = 0;}if (params.x > winWidth - view_toastrocket.getWidth()) {params.x = winWidth - view_toastrocket.getWidth();}if (params.y > winHeight - view_toastrocket.getHeight()) {params.y = winHeight - view_toastrocket.getHeight();}mWM.updateViewLayout(view_toastrocket, params); // 更新图片在屏幕上的位置startx = (int) event.getRawX();starty = (int) event.getRawY();break;case MotionEvent.ACTION_UP:if (params.x > 100 && params.x < 250) {if (params.y > 300) {sendRocket();}}default:break;}return true;}});}

3 用户抬起时（MotionEvent.ACTION_UP）发射火箭：

if (params.x > 100 && params.x < 250) {if (params.y > 300) {sendRocket();}}

4 添加权限：

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>

2 使用子线程更新火箭发射功能

1 创建Thread子线程：

new Thread(){@Overridepublic void run() {// TODO Auto-generated method stubsuper.run();}}.start();

2 使用handler 更新视图

 由于在子线程中无法更新视图（视图只能在主线程中进行更新），所以使用handler的handeMessage接收子线程发送的消息来实现更新界面视图。

 （1）创建一个handler，并重写handlemessage

private Handler mHandler = new Handler() {public void handleMessage(android.os.Message msg) {};};

（2）拼接一个Message发送给handler

Message message = Message.obtain();message.arg1 = params.y;mHandler.sendMessage(message);

（3）在handleMessage中更新视图：

mWM.updateViewLayout(view_toastrocket, params);

过程：

private Handler mHandler = new Handler() {public void handleMessage(android.os.Message msg) {int y = msg.arg1;params.y = y;mWM.updateViewLayout(view_toastrocket, params);};};protected void sendRocket() {// for (int i = 300; i >= 0; i++) {// params.y = i;// mWM.updateViewLayout(view_toastrocket, params);// }System.out.println("发射火箭！！！");new Thread() { // 创建一个子线程进行更新@Overridepublic void run() {System.out.println("子线程");params.x = winWidth / 2 - view_toastrocket.getWidth() / 2;for (int i = 0; i < 10; i++) {params.y = 380 - 38 * i;Message message = Message.obtain();message.arg1 = params.y;mHandler.sendMessage(message);// mWM.updateViewLayout(view_toastrocket, params);// //无法再子线程中更新视图/** 在主线程中使用thread.sleep会导致主线程阻塞，发生崩溃*/try {Thread.sleep(100);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}.start();}

3 使用handle.post在主线程中充当延时函数

new Handler().postDelayed(new Runnable() { //运行在主线程中@Overridepublic void run() {finish();				}}, 1000);

package com.example.rocket2;import android.R.anim;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.animation.AlphaAnimation;
import android.widget.ImageView;public class BackGroundActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.background_activity);ImageView msmoke = (ImageView)findViewById(R.id.iv_smoke_m);ImageView  tsmoke =(ImageView) findViewById(R.id.iv_smoke_t);AlphaAnimation animi = new AlphaAnimation(0, 1);animi.setDuration(1000);animi.setFillAfter(true);tsmoke.startAnimation(animi);msmoke.startAnimation(animi);new Handler().postDelayed(new Runnable() { //运行在主线程中@Overridepublic void run() {finish();				}}, 1000);}
}