android - 如何从服务转到主屏幕？

Question

我有这个 MainService，一旦启动，它会关闭屏幕并仅在计时器结束后打开它(此外，所述服务也会在计时器结束后停止)。

我的问题是:有没有办法让应用程序也进入后台，就在屏幕关闭之前？进入后台是指出现主屏幕。

主要 Activity :

public class MainActivity extends AppCompatActivity {

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

    final Button startApp = (Button) findViewById(R.id.startApp);
    final EditText timer = (EditText) findViewById(R.id.insertTimer);

    assert startApp != null;
    startApp.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Toast.makeText(MainActivity.this, "Countdown, Started", Toast.LENGTH_SHORT).show();

            Intent intent = new Intent(MainActivity.this, MainService.class);

            assert timer != null;
            intent.putExtra("timer", timer.getText().toString());

            Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_OFF_TIMEOUT, 1000);

            registerReceiver(broadcastReceiver, new IntentFilter(MainService.BROADCAST_ACTION));

            startService(intent);
        }
    });
}

private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        updateUI(intent);
    }
};

private void updateUI(Intent intent) {
    String counter = intent.getStringExtra("counter");
    TextView txtCounter = (TextView) findViewById(R.id.txtCounter);
    assert txtCounter != null;
    txtCounter.setText(counter);
}

主要服务:

public class MainService extends Service {

public static final String BROADCAST_ACTION = "com.example.vladpintea.friendsbeforecents.displayevent";
private final Handler handler = new Handler();
int counterr = 0;
Intent intentt;

String usedTimer;
long interval;

//TimerTask that will cause the run() runnable to happen.
TimerTask myTask = new TimerTask() {
    public void run() {
        stopSelf();
    }
};
//Timer that will make the runnable run.
Timer myTimer = new Timer();

@Override
public void onCreate() {
    intentt = new Intent(BROADCAST_ACTION);

    registerReceiver(counter, new IntentFilter(Intent.ACTION_SCREEN_ON));

    Toast.makeText(MainService.this, "Service, Created", Toast.LENGTH_SHORT).show();
}

private BroadcastReceiver counter = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(MainService.this, "Whoops! You've Lost.", Toast.LENGTH_SHORT).show();
        Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_OFF_TIMEOUT, 30000);
    }
};

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    Toast.makeText(MainService.this, "Service, Started", Toast.LENGTH_SHORT).show();

    usedTimer = intent.getStringExtra("timer");
    try {
        interval = Long.parseLong(usedTimer);
    } catch (NumberFormatException ignored) {}

    myTimer.schedule(myTask, interval);

    handler.removeCallbacks(sendUpdatesToUI);
    handler.postDelayed(sendUpdatesToUI, 1000);

    return super.onStartCommand(intent, flags, startId);
}

private Runnable sendUpdatesToUI = new Runnable() {
    public void run() {
        handler.postDelayed(this, 1000);
    }
};

public void DisplayLoggingInfoPlus() {
    intentt.putExtra("counter", String.valueOf(++counterr));
    sendBroadcast(intentt);
}

@Override
public void onDestroy() {
    DisplayLoggingInfoPlus();

    PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
    PowerManager.WakeLock wakeLock = pm.newWakeLock(PowerManager.FULL_WAKE_LOCK
            | PowerManager.ACQUIRE_CAUSES_WAKEUP
            | PowerManager.ON_AFTER_RELEASE, "MyWakeLock");
    wakeLock.acquire();

    Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_OFF_TIMEOUT, 30000);
}

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

Answer 1

使用this post查看如何触发手动按下的 home。现在只需在您希望此行为发生的任何地方触发此代码，例如在锁定屏幕的计时器中。