I've been wondering if it is possible to use an IntentService to do some networking while keeping the queue of pending intents prioritized. My goal to be able to download some images in the background, add more if needed (send another Intent) and be able to reset the queue if necessary (preferably using a specific Intent). That is all possible with an IntentServie but when I send that 'stop' Intent it needs to be processed as the next item in the queue, not the last where it is right now.
EDIT
For those interested I have taken the AOSP code for IntentService and modified it to meet my needs. The reason I cannot just subclass IntentHandler is because of the private ServiceHandler class inside of IntentHandler.
Inside of the ServiceHandler I have a new method:
public final boolean sendPriorityMessage(Message msg)
{
int priority = msg.arg2;
//Log.i(GenericList.TAG,"recieved message priority: "+priority);
if(priority>PRIORITY_NORMAL){
return sendMessageAtFrontOfQueue(msg);
}else{
return sendMessage(msg);
}
}
This method is called from onStart instead of just sendMessage
#Override
public void onStart(Intent intent, int startId) {
Message msg = mServiceHandler.obtainMessage();
msg.arg1 = startId;
msg.obj = intent;
try{
msg.arg2 = intent.getExtras().getInt(KEY_PRIORITY);
}catch(Exception e){
msg.arg2 = PRIORITY_NORMAL;
}
mServiceHandler.sendPriorityMessage(msg);
}
Overall the code is still limited but I am able to fast track some messages to the front of the queue, which is what I was after anyway.
you could implement/extend your own PriorityQueue that simply checks every new intent added to the queue. if it's the stop intent, it moves it straight to the front of the line.
Related
Im trying to implement MVVM architecture using ViewModel and LiveData. These two methods are inside a Activity:
private void handleResult(BoardViewModel vm) {
vm.getLiveDataSingleObj("Result").observe(this, new Observer<Object>() {
#Override
public void onChanged(#Nullable Object resultObj) {
Result result = (Result) resultObj;
if (!result.isCompleted()) return;
gotoResult();
}
});
}
And
private void gotoResult() {
Log.w(LOG_TAG, "Result: Moving to next activity");
Intent intent = new Intent(boardActivity, ResultActivity.class);
intent.putExtra("LEVEL", levelIndex);
intent.putExtra("MAP", mapIndex);
startActivity(intent);
}
The handleResult method is setup to listen for result objects that indicate that the game has ended and it is time to move on to the next activity ("gotoResult"). However, this completely breaks the navigation of the app, when i go back and then say attempt to start a new game session i instead instantly go to the next activity telling me I've already won.
Any ideas as to why it fires multiple times and eventually stops, letting me start a new session. To clarify, if I remove the gotoResult the logic works every single time no errors with indexes out of bounds or what have you, it's only when I add the goto that everything breaks.
ViewModel:
private void setupHashTypes() {
hashLiveData.put(KEY_BOARD, liveDataBoardQuery);
hashLiveData.put(KEY_STEPS_COUNTER, game.getStepsTakenLiveData());
hashLiveData.put(KEY_PATH_CHANGE, game.getPathChangedLiveData());
hashLiveData.put(KEY_VALUE_CHANGE, game.getValueChangeLiveData());
hashLiveData.put(KEY_TIMER, game.getTimerLiveData());
hashLiveData.put(KEY_SELECTED, game.getSelectedLiveData());
hashLiveData.put(KEY_DESELECTED, game.getDeselectedLiveData());
hashLiveData.put(KEY_HOLD, game.getHoldLiveData());
hashLiveData.put(KEY_UNHOLD, game.getUnholdLiveData());
hashLiveData.put(KEY_RESULT, game.getResultLiveData());
}
public LiveData<Object> getLiveDataSingleObj(String type) {
if (hashLiveData.containsKey(type)) {
return (LiveData<Object>) hashLiveData.get(type);
}
throw new IllegalArgumentException("Invalid: key was not found: " + type);
}
And the Model has getters, example:
private final SingleLiveEvent<Result> resultLiveData = new SingleLiveEvent<>();
public LiveData<Result> getResultLiveData() {
return resultLiveData;
}
you should remove the observer in onDestroy() method
Changing from MutableLiveData which always resends the previous set values to new subscribers, to SingleLiveEvent which doesn't have this behaviour, solved the problem.
The class can be found here: https://github.com/googlesamples/android-architecture/tree/dev-todo-mvvm-live/todoapp/app/src/main/java/com/example/android/architecture/blueprints/todoapp
I won't show a received push notification from appearing top notifications menu my notification if it has for example key update. For now if I get notification with this key, all notifications are in the notification bar. I want to not present this notifications for user.
I'm using WakefulBroadcastReceiver for handle notifications like below:
public class PusherReceiver extends WakefulBroadcastReceiver {
private boolean isAppOnForeground(Context context) {
ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
if (appProcesses == null)
return false;
final String packageName = context.getPackageName();
for (ActivityManager.RunningAppProcessInfo appProcess : appProcesses) {
if (appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND && appProcess.processName.equals(packageName)) {
return true;
}
}
return false;
}
public void onReceive(final Context context, Intent intent) {
Log.i("SimpleWakefulReceiver", "Starting service # " + SystemClock.elapsedRealtime());
if (!isAppOnForeground((context))) {
String pushNotificationBody = intent.getStringExtra("alert");
try {
JSONObject notificationData = new JSONObject(pushNotificationBody);
// This is the Intent to deliver to our service.
Intent service = new Intent(context, BackgroundService.class);
// Put here your data from the json as extra in in the intent
service.putExtra("notification", pushNotificationBody);
Log.i("PUSH_NOTIFICATION_JSON", "RECEIVED JSON " + notificationData);
// Start the service, keeping the device awake while it is launching.
if (!notificationData.has("update")) {
startWakefulService(context, service);
} else {
// Do nothing
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
UPDATE:
I changed project a little and with Onesignal and his NotificationExtenderService, I did something like below:
public class NotificationNotDisplayingExtender extends NotificationExtenderService {
#Override
protected boolean onNotificationProcessing(OSNotificationReceivedResult receivedResult) {
String notification = receivedResult.toString();
String notificationBody = receivedResult.payload.body;
JSONObject notificationBodyJSON = null;
try {
notificationBodyJSON = new JSONObject(notificationBody);
} catch (JSONException e) {
e.printStackTrace();
}
JSONObject pushNotificationData = notificationBodyJSON;
boolean hidden = false;
if (pushNotificationData.has("update")) {
Log.i("NOTIFICATION MANAGER", "PREVENT DISPLAY NOTIFICATION");
hidden = true;
}
// Return true to stop the notification from displaying.
return hidden;
}
}
And it prevent displaying notifications with update key, but now I don't receive it in my PusherReceiver to start my service. Is there easy way to send data from my NotificationNotDisplayingExtender receivedResult to my PusherReceiver?
For now it looks like my PusherReceiver don't fire his onReceive method.
Many thanks for help in advance.
There are two types of payload.
1. Data
2. Notification
https://developers.google.com/cloud-messaging/concept-options
Use only data payload. Then you always get the call in FirebaseMessagingService onMessageRececived Method
The thing is basically we have two type of notifications.
One which can be called Notification Type, is that the push has a notification object in sent/received bundle, in which you have to handle it when your app is in foreground and the notification is received. In this case, if your app is in foreground, then you can handle it and do whatever you like which is not showing a notification. But if the app is in background, a notification will automatically create by google and it takes predefined title and message objects within the received push bundle to make the notification.
Second type which can be called Data Type, do not have any notification object in the sent/received bundle. In this scenario, your app is in foreground or background, you should handle everything. So, if you put your data in data object of your push notification message, everything will be in your hands.
So, in short, just put your data in data object of your notification and implement your desired logic.
I do not see the JSON data you are referring to. However, I suppose the update key in your JSON is containing null. In your code you are checking if the JSON data has the key update in it. This function will always return true if the key exists in the JSON body. You might have the field with null value which is indicating that you are not supposed to show the notification in the system tray.
In that case, you might consider using isNull function. It returns true if this object has no mapping for update or if it has a mapping whose value is null.
// Start the service, keeping the device awake while it is launching.
if (!notificationData.isNull("update")) {
startWakefulService(context, service);
} else {
// Do nothing
}
And yes, please use the data payload from the notification that you get.
Every time you notify the NotificationManager to show a notification, you provide an ID to be used for the notification to edit or cancel that notification later on. If you show a notification by manager.notify(notificationId, notification), you can cancel it with manager.cancel(notificationId).
If you want to remove all the notifications, you can use NotificationManager.cancelAll().
I have a class in a service
MyClass m = new MyClass();
and inside my class I check if I have permission to overlay the view; if so, it's ok, otherwise I must start an activity
if (Settings.canDrawOverlays(mContext)) {
// draw over app
} else {
// start the activity
Intent i = new Intent(context,Calls.class);
context.startActivity(i);
}
When I start the activity I have a problem communicating between the class and the activity. I know how to use the interface but how can I register it in activity.
Some time I want to pass an object or data from the class to the activity or from the activity to the class... how can I do that?
I saw many examples in Stack Overflow about how to communicate between service and activity; they suggest to start the class from the activity but this does not work in my app because my class must be running all the time.
Perhaps you could use an event bus like mechanism where you can send or receive events through out your app, Though there are several libraries out there, I would recommend using Otto library for android.
Usage is pretty simple just register in your activity onCreate
Bus bus = new Bus();
bus.register(this);
For sending events
// example data to post
public class TestData {
public String message;
}
// post this data
bus.post(new TestData().message="Hello from the activity");
And subscribe to events like this
#Subscribe public void getMessage(TestData data) {
// TODO: React to the event somehow!
}
More info here
If you want to implement a communication pattern between a Service and an Activity, you should use a LocalBroadcastManager.
It will turn handy because, in case your Service is still on but your Activity
has been destroyed (very common situation), then the 'messagging' between the two will simply have no effect (no NPE or whatsoever will be thrown).
Step 1
Create a BroadcastReceiver in your Activity and define an ID / Filter
this.localBroadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
// Do what you have to do here if you receive data from the Service / Background Task
}
}
public static final IntentFilter SIGNAL_FILTER = new IntentFilter("com.you.yourapp.MY_SIGNAL")
Step 2
In your Activity register the broadcast in onResume() and unregister it in onPause().
#Override
protected void onResume() {
// Listen if a Service send me some data
LocalBroadcastManager.getInstance(getApplicationContext()).registerReceiver(this.localBroadcastReceiver, SIGNAL_FILTER);
}
#Override
protected void onPause() {
// I'm going to the background / or being destroyed: no need to listen to anything anymore...
LocalBroadcastManager.getInstance(getApplicationContext()).unregisterReceiver(this.localBroadcastReceiver);
}
Your Activity is now ready to receive data from any other component in your Application.
If it's in the background, then there is no need to update the UI: in fact the Activity will not respond if in the background.
In the same way, if it's being garbage collected, the Receiver will be unregistered and the Activity will just not respond to anything.
If the Activity is resumed / restarted, onResume() will be triggered and the Receiver will be registered again.
Step 3
All you need to do right now, is send data from the Service.
Simply call
final Intent intent = new Intent();
intent.setAction(SomeActivity.SIGNAL_FILTER);
// put your data in intent
LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(intent);
and your Activity will accordingly respond to the signal.
It's surprising how few people know about the LocalBroadcastManager and instead use some self-implemented callback / singleton pattern, which increases complexity and non-readability.
This pattern is built-in in Android, so you don't need external libraries. As for security, this ensures that your signals stay internal to your application: no data can therefore be read by other apps.
I similarly answered to another question here.
i have a class(location2.java) that finds location for me,I use this code in my class :
What is the simplest and most robust way to get the user's current location on Android?
and I have a service that override that abstract "locationResult";Now i want my service after running its codes,service doesn't finish and stay alive for receiving location from location2.java.
appreciating any help for this.
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Location2.LocationResult locate = new Location2.LocationResult() {
#Override
public void gotLocation(Location location1, Boolean Gps, Boolean Net) {
if (location1 != null) {
Log.e("Loc", String.valueOf(location1.getLatitude()));
}
try {
//this is a method that i want to be run after receiving location from location2.java
json_maker(location1, speed_computation(location1), Gps, Net);
} catch (JSONException e) {
e.printStackTrace();
}
}
};
Location2 location = new Location2();
location.getLocation(context, locate);
return Service.START_FLAG_REDELIVERY;
}
The most successful way is to use return START_STICKY.
"and if service wants to restart, multiple constants for example START_STICKY can be used.doesn't it?" - Yes, we can use.
START_STICKY
Constant to return from onStartCommand(Intent, int, int) if this service's process is killed while it is started (after returning from onStartCommand(Intent, int, int)), then leave it in the started state but don't retain this delivered intent. Developer guide: Android
I search a lot and I tried several ways but I couldn't find anything that avoid my error.
I'm working on app for my learning, where is an String in my MainActivity and then I call it in my Service. I tried something like this:
This next one goes in my myService.class
//In my myService.class that extends Service
public class myService extends Service{
AlarmManager manager;
PendingIntent pintent;
String te;
#Override
public void onCreate()
{
manager = (AlarmManager)(this.getSystemService(Context.ALARM_SERVICE));
pintent = PendingIntent.getBroadcast( this, 0, new Intent("blahblah"), 0 );}
#Override
public int onStartCommand(Intent intent, int flags, int startid)
{
super.onStartCommand(intent, flags, startid);
te = intent.getStringExtra("tst"); //if I change this line to te = "something", everything goes fine
BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive( Context context, Intent intent )
{
Toast.makeText(getApplicationContext(),te, Toast.LENGTH_SHORT).show();
}
};
this.registerReceiver(receiver, new IntentFilter("blahblah") );
// set alarm to fire 30 min and waits 2 min
manager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime() + 1000*30*60, 1000*2*60, pintent);
return START_STICKY;}
public IBinder onBind(Intent p1)
{
// TODO: Implement this method
return null;
}
}
Here the code runs perfectly, but when I exit my App, it crashes. After 1 minute, my device shows again that my App crashes, confirming my app "successfully" ran into background. What is wrong with it?
I also learned I could use IntentService instead of Service, wich one is better for long tasks and what is the difference between them ?
EDIT***
I received the following error: java.lang.NullPointerExeption.
So I change this:
te = intent.getStringExtra("tst");
To this:
try
{
te = intent.getStringExtra("tst");
}
catch(NullPointerException e)
{}
When I changed it my app works with any error, but The problem is: I need to retrieve my String from my MainActivity, when I close my app my service runs without errors but my "te" String takes null valor, what can I do to "save" my String in my service, to be able to use it and keeping showing the "working" message after I close my App ? Should I use SharedPreferences ?
Hope I was clear.
IntentService is different from Service.
IntentService Self kills the service as it finishes the task. Whereas Service runs for ever unless you kill it.
For my coding experience, I would use IntentService only for small tasks that run for a couple of seconds and use Service for long running one and call StopSelf() as needed.
Kindly post the log to answer your problem