问题
I'm trying to create a service where I want to detect something about user, let's say when user lays the device on a table, the thing is that I have that action detected but I have it on a MainActivty
and I want it to put on Service
.
The thing is that on my MainActivity()
I had my registerAction()
and on my onResume()
were called and in onPause()
I call the unregisterListener()
from my sensor
, as well I have a HandlerThread
where I start it on my onCreate()
how do I change it to Service
? Would be a problem? I see that there aren't the same methods...
I've created my Service
and I've got :
public class MyService extends Service {
public MyService() {
}
@Override
public IBinder onBind(Intent intent) {
// TODO: Return the communication channel to the service.
throw new UnsupportedOperationException("Not yet implemented");
}
@Override
public void onCreate() {
super.onCreate();
Log.d("CREATE","ONCREATE");
}
@Override
public void onDestroy() {
super.onDestroy();
Log.d("DESTROY","ONDESTROY");
}
}
Also my MainActivity
I have put implements SensorEventListener
.
A skeleton of my class is :
public class MainActivity extends Activity implements SensorEventListener {
private HandlerThread mSensorThread;
private SensorManager mSensorManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mSensorThread = new HandlerThread("sensor_thread");
mSensorThread.start();
}
private void registerSensorListener() {
mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_FASTEST, new Handler(mSensorThread.getLooper()));
}
@Override
public void onSensorChanged(SensorEvent event) {
//DO stuff
if (isLayed()) {
runOnUiThread(new Runnable() {
@Override
public void run() {
Log.d("LAY","LAYLAY");
}
});
mSensorManager.unregisterListener(this);
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
private boolean isLayed() {
return stuff;
}
@Override
protected void onResume() {
super.onResume();
registerSensorListener();
}
@Override
protected void onPause() {
super.onPause();
mSensorManager.unregisterListener(this);
}
}
EDIT
I'm using szamani20 code, but I'm having problems with runOnUiThread
because I can not call from my Service
also, I'm having this issue
java.lang.RuntimeException: Unable to start service com.example.developer.qwe.MyService@d8c613b with null: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getAction()' on a null object reference
回答1:
First of all you need to decide whether you want the user to be aware of your running service or not. Take a review on Background Execution Limits in android Oreo:
To improve the user experience, Android 8.0 (API level 26) imposes limitations on what apps can do while running in the background.
So considering your case where it seems there are lots of work to do in many situations, it would be a better approach to use a foreground service. As android document says about foreground services:
A foreground service is a service that the user is actively aware of and is not a candidate for the system to kill when low on memory. A foreground service must provide a notification for the status bar, which is placed under the Ongoing heading. This means that the notification cannot be dismissed unless the service is either stopped or removed from the foreground.
Since you mentioned that you have the action detected I won't enter that part of your code. So you need to create a subclass of Service
as you did and use the startService
method to get it's onCreate
called. One thing you need to notice is that the onCreate
method of service is called once you call startService
on that service for the first time, no matter how many times you call startService
again the onCreate
method won't get called and only the onStartCommand
get called. We use that fact alongside that you could provide a string action within your intent
to properly register and unregister your listener.
In MainActivity.java
:
String action = "start"; // Or to unregister listener "stop"!
final Intent intent = new Intent(this, MyService.class);
intent.setAction(action);
startService(intent);
and then in MyService.java
:
@Override
public void onCreate() {
super.onCreate();
// Do initialization or whatever here (executed once per service lifecycle)
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
if (intent.getAction().equals("start")) {
// Register your listener or whatever
showForegroundNotification();
}
if (intent.getAction().equals("stop")) {
// Unregister your listener or whatever
stopForeground(true);
stopSelf();
}
return START_STICKY;
}
private void showForegroundNotification() {
Intent myServiceNotificationIntent = new Intent(this, MainActivity.class);
myServiceNotificationIntent.setFlags(
Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
PendingIntent pendingIntent = PendingIntent
.getActivity(this, MY_SERVICE_REQUEST_CODE,
myServiceNotificationIntent, MY_SERVICE_FLAG);
Notification notification = new NotificationCompat.Builder(this)
.setContentTitle(MY_SERVICE_NOTIFICATION_CONTENT_TITLE)
.setTicker(MY_SERVICE_NOTIFICATION_TICKER)
.setContentText(MY_SERVICE_NOTIFICATION_CONTENT_TEXT)
.setSmallIcon(R.drawable.ic_whatever)
.setContentIntent(pendingIntent)
.setOngoing(true)
.build();
startForeground(MY_SERVICE_NOTIFICATION_ID, notification);
}
Finally don't forget to unregister your listener in onDestroy
in case of android kill your service (which is very rare):
@Override
public void onDestroy() {
super.onDestroy();
// Unregister your listener
}
回答2:
You can register SensorManager inside service in OnStartCommand.Also try using startForeground as android os will kill your service when app is killed
来源:https://stackoverflow.com/questions/46958600/create-service-to-detect-any-action-from-the-user