Android的Service應用程序組件基本編寫方法

Service是什麼
Service是一個android 系統中的應用程序組件，它跟Activity的級別差不多，但是他沒有圖形化界面，不能自己運行，只能後台運行，並且可以和其他組件進行交互如更新ContentProvider，Intent以及系統的通知等等。其啟動方式有兩種：context.startService() 和 context.bindService()。Service通常用來處理一些耗時比較長的操作。

Service的編寫
創建一個類（這裡為FirstService）繼承android.app.Service，並覆蓋以下方法：
onBind(Intent intent) Return the communication channel to the service.
onCreate() Called by the system when the service is first created.
onStartCommand(Intent intent, int flags, int startId) Called by the system every time a client explicitly starts the service by calling startService(Intent), providing the arguments it supplied and a unique integer token representing the start request.
onDestroy() Called by the system to notify a Service that it is no longer used and is being removed.

AndroidManifest.xml文件中添加service配置
復制代碼 代碼如下:
<service android:name=".FirstService"></service>

在Activity中啟動和停止Service的點擊事件的編寫
復制代碼 代碼如下:
class StartServiceListener implements OnClickListener {
@Override
public void onClick(View v) {
Intent intent = new Intent();
intent.setClass(TestActivity.this, FirstService.class);
startService(intent);
}
}
class StopServiceListener implements OnClickListener {
@Override
public void onClick(View v) {
Intent intent = new Intent();
intent.setClass(TestActivity.this, FirstService.class);
stopService(intent);
}
}