Question

有没有办法确保服务在启动后继续在后台运行，即使用户从最近屏幕清除应用程序？一个完美的例子就是潘多拉的应用程序，一旦它开始播放，即使你从最近清除它，音乐仍然在播放，通知仍然存在。

在我的示例应用程序中，我有一个简单的处理程序，只记录当前时间500毫秒，所以我可以看到服务是否正在运行，并且我使用4个切换之一启动它，每个切换设置为使其开始4个服务启动类型（START_STICKY，START_NOT_STICKY，START_REDELIVER_INTENT，START_STICKY_COMPATIBILITY）。我启动服务，退出应用程序，然后从最近清除它。在每种情况下，服务都会终止并且循环日志记录停止。

MainActivity.java

public class MainActivity extends Activity {

    private Boolean recording = false;
    private Intent recordingService;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        recordingService = new Intent(this, RecordingService.class);

        Button START_STICKY = (Button) findViewById(R.id.START_STICKY);
        START_STICKY.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View arg0) {
                startStopRecordingService(Service.START_STICKY);
            }
        });

        Button START_NOT_STICKY = (Button) findViewById(R.id.START_NOT_STICKY);
        START_NOT_STICKY.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View arg0) {
                startStopRecordingService(Service.START_NOT_STICKY);
            }
        });

        Button START_REDELIVER_INTENT = (Button) findViewById(R.id.START_REDELIVER_INTENT);
        START_REDELIVER_INTENT.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View arg0) {
                startStopRecordingService(Service.START_REDELIVER_INTENT);
            }
        });

        Button START_STICKY_COMPATIBILITY = (Button) findViewById(R.id.START_STICKY_COMPATIBILITY);
        START_STICKY_COMPATIBILITY.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View arg0) {
                startStopRecordingService(Service.START_STICKY_COMPATIBILITY);
            }
        });
    }

    private void startStopRecordingService(int START_TYPE) {
        if (recording) {
            recordingService.removeExtra(RecordingService.START_TYPE);
            stopService(recordingService);
        } else {
            recordingService.putExtra(RecordingService.START_TYPE, START_TYPE);
            startService(recordingService);
        }

        recording = !recording;
    }
}

RecordingService.java

public class RecordingService extends Service
{
    public final static String START_TYPE = "START_TYPE";

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startID) {
        Log.i(getClass().getName(), "onStartCommand");

        int start_type = intent.getExtras().getInt(START_TYPE);
        Log.i(getClass().getName(), "START_STICKY: " + String.valueOf(start_type == Service.START_STICKY));
        Log.i(getClass().getName(), "START_NOT_STICKY: " + String.valueOf(start_type == Service.START_NOT_STICKY));
        Log.i(getClass().getName(), "START_REDELIVER_INTENT: " + String.valueOf(start_type == Service.START_REDELIVER_INTENT));
        Log.i(getClass().getName(), "START_STICKY_COMPATIBILITY: " + String.valueOf(start_type == Service.START_STICKY_COMPATIBILITY));

        logTime();

        return start_type;
    }

    @Override
    public void onDestroy() {
        Log.i(getClass().getName(), "onDestroy");
        updateDisplayTimer.removeCallbacks(updateDisplayHandler);
    }

    public void logTime() {
        Log.i(getClass().getName(), String.valueOf(System.currentTimeMillis()));
        updateDisplayTimer.postDelayed(updateDisplayHandler, LOOP_TIME);
    }

    private static final int LOOP_TIME = 500;
    private Handler updateDisplayTimer = new Handler();
    private Runnable updateDisplayHandler = new Runnable() {
        @Override
        public void run() {
            logTime();
        }
    };
}

Answer 1

尝试实施前台服务。 foreground service

前台服务显示通知，永不停止。

在您的服务中实施此代码段

Notification notification = new Notification(R.drawable.icon, getText(R.string.ticker_text),
        System.currentTimeMillis());
Intent notificationIntent = new Intent(this, ExampleActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
notification.setLatestEventInfo(this, getText(R.string.notification_title),
        getText(R.string.notification_message), pendingIntent);
startForeground(ONGOING_NOTIFICATION_ID, notification);

即使应用程序被清除，如何保持服务运行？

1 个答案: