Binder 讣告应用于进程守护

Binder 讣告应用于进程守护

Binder 应用于C/S通信中，有时候Server可能需要知道Client进程是否存在，当Client挂掉后，Server可以及时清理资源。
利用这种机制，同样可以实现简单的程序守护，当Client崩溃后，Server帮助重启Client程序。

守护程序

守护程序开放一个Service，提供给被守护程序调用

• AIDL

ample.guardapp;
import android.os.IBinder;interface IGuardService {void attachBinder(IBinder token);
}

• Service

public class GuardService extends Service {private static final String TAG = "GuardService";private static final String MAIN_APP_PACKAGE = &#ample.mainapplciation";private static final String MAIN_MAIN_ACTIVITY = &#ample.mainapplciation.MainActivity";private IGuardService.Stub mStub = new IGuardService.Stub() {@Overridepublic void attachBinder(IBinder token) throws RemoteException {//客户端注册死亡讣告token.linkToDeath(recipient, 0);}};private IBinder.DeathRecipient recipient = new IBinder.DeathRecipient() {@Overridepublic void binderDied() {//侦听到客户端死亡，重启客户端主程序restartMainApp();}};private void restartMainApp() {Intent intent = new Intent(Intent.ACTION_MAIN);intent.addCategory(Intent.CATEGORY_LAUNCHER);ComponentName cn = new ComponentName(MAIN_APP_PACKAGE, MAIN_MAIN_ACTIVITY);intent.setComponent(cn);intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);startActivity(intent);}@Overridepublic IBinder onBind(Intent intent) {return mStub;}
}

被守护程序

主程序即被守护程序，只要调用远程的GuardService接口即可。

//客户端Binder
private Binder mBinder = new Binder();
private ServiceConnection mConnection = new ServiceConnection() {@Overridepublic void onServiceConnected(ComponentName name, IBinder service) {IGuardService guardService = IGuardService.Stub.asInterface(service);try {guardService.attachBinder(mBinder);} catch (RemoteException e) {e.printStackTrace();}}@Overridepublic void onServiceDisconnected(ComponentName name) {}
};private void bindGuardService() {Intent intent = new Intent();intent.setPackage(GUARD_APP_PACKAGE);intent.setAction(GUARD_SERVICE_ACTION);bindService(intent, mConnection, BIND_AUTO_CREATE);}

测试

使用adb kill 杀掉主程序，观察主程序是否重启。

示例

查看demo