使用Service服务后台运行Toast显示小火箭

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;

@Override
public 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(){
@Override
public void run() {
// TODO Auto-generated method stub
super.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
@Override
public 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 block
e.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

@Override
public 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 {

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.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

@Override
public void run() {
finish();
}
}, 1000);
}
}