Develop Reference

Is there a reliable way for androidx.lifecycle.DefaultLifecycleObserver to detect app quit event?

Currently, I'm using androidx.lifecycle.DefaultLifecycleObserver, to execute some code when the app is "quit". How I define "quit" are
When HOME button is pressed and app is not visible on screen.
When BACK button is pressed (one time or multiple times) till the app is not visible on screen.
This DOES NOT include when you launch a child activity, and causes onPause of main activity being triggered.
This DOES NOT include configuration change like phone rotation
As such, I using the following way to capture "quit" event.
public class WeNoteApplication extends MultiDexApplication {
public static class AppLifecycleObserver implements DefaultLifecycleObserver {
#Override
public void onResume(LifecycleOwner owner) {
// Capture "launch" event when app is "launched"
}
#Override
public void onPause(LifecycleOwner owner) {
// Capture "quit" event when app is "quit"
}
}
private static final AppLifecycleObserver appLifecycleObserver = new AppLifecycleObserver();
private static WeNoteApplication me;
private SharedPreferences sharedPreferences;
#Override
public void onCreate() {
super.onCreate();
me = this;
initLifecycleObserver();
}
private void initLifecycleObserver() {
Lifecycle lifecycle = ProcessLifecycleOwner.get().getLifecycle();
lifecycle.removeObserver(appLifecycleObserver);
lifecycle.addObserver(appLifecycleObserver);
}
public static WeNoteApplication instance() {
return me;
}
}
This works well most of the time but all the time.
The following is the edge case which makes app "quit" event failed.
Assume there is a home screen widget for the app.
The following code is executed when a component of the home screen widget is being pressed.
Intent i = new Intent(context, NoteListAppWidgetConfigureFragmentActivity.class);
// Avoid crash in Android 6.
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_TOP);
i.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
i.putExtra(NoteListAppWidgetConfigureFragmentActivity.INTENT_EXTRA_NOTE_LIST_CONFIG, noteListConfig);
context.startActivity(i);
Press back button to quit the home widget launched Activity.
Launch the app again by tapping app icon.
Press back button to quit the app. We notice that DefaultLifecycleObserver's onPause is not called.
Is there a reliable way for androidx.lifecycle.DefaultLifecycleObserver to detect app quit event?

This is because in our configuration activity for home screen widget, we're calling super.onPause twice. This makes DefaultLifecycleObserver goes hair-wire.
public class StickyNoteAppWidgetConfigureFragmentActivity extends AppCompatActivity {
#Override
public void onPause() {
super.onPause();
// ...
// ...
// ...
super.onPause();
}
}
We simply fix it by removing call of extra super.onPause().
public class StickyNoteAppWidgetConfigureFragmentActivity extends AppCompatActivity {
#Override
public void onPause() {
super.onPause();
// ...
// ...
// ...
}
}

Check if activity onStop is called while starting a new activity

I am trying to solve a problem. In my application I need to determine if onStop method was called because of starting a new activity or it was called after user had clicked on the home button or had switched to another app.
I have BaseActivity class, and I need to check it here.
I have tried to find a way to do this, but unfortunately still no solution is found.
Maybe there is a workaround for that.
The idea is to differentiate the initiator of onStop method call.
I would be grateful for any help.

A possible solution would be to register an ActivityLifecycleCallbacks and save the reference name of the last activity that called onResume:
public class ActivityChecker implements Application.ActivityLifecycleCallbacks {
private static ActivityChecker mChecker;
private String mCurrentResumedActivity = "";
public static ActivityChecker getInstance() {
return mChecker = mChecker == null ? new ActivityChecker() : mChecker;
}
// If you press the home button or navigate to another app, the onStop callback will be called without touching the mCurrentResumedActivity property.
// When a new activity is open, its onResume method will be called before the onStop from the current activity.
#Override
public void onActivityResumed(Activity activity) {
// I prefer to save the toString() instead of the activity to avoid complications with memory leaks.
mCurrentResumedActivity = activity.toString();
}
public boolean isTheLastResumedActivity(#NonNull Activity activity) {
return activity.toString().equals(mCurrentResumedActivity);
}
// [...] All other lifecycle callbacks were left empty
}
The ActivityLifecycleCallbacks can be registered in your Application class:
public class App extends Application {
public App() {
registerActivityLifecycleCallbacks(ActivityChecker.getInstance());
}
}
Don't forget to register it in your manifest:
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="your.package.name">
<application
...
android:name=".App"
> ...
</application>
</manifest>
Then, you can use it in your base Activity.
public class MyBaseActivity {
#Override protected void onStop() {
if(ActivityChecker.getInstance().isTheLastResumedActivity(this)) {
// Home button touched or other application is being open.
}
}
}
References:
Registering your custom Application class and the ActivityLifecycleCallbacks: https://developer.android.com/reference/android/app/Application.html
After writing this I found this link with some other options to retrieve the current resumed activity: How to get current foreground activity context in android?.

You can use SharedPreferences to check it:
#Override
protected void onStop() {
super.onStop();
SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(this);
pref.edit().putBoolean("IfOnStopCalled", true).apply();
}
Check in your BaseActivity:
SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(this);
Boolean IfOnStopCalled = pref.getBoolean("IfOnStopCalled",false);
if(IfOnStopCalled){
//Do your action
}
else{
//Do your action
}

Android - How to know when app has been resumed after being in background

I'm trying to determine when my app is being resumed after the user closed it, in any way, pressing home button, back button or switching to another app.
What I need to do is to set a boolean when the app goes in background, so, when it is resumed, I know that it was in background before and I can act accordingly.
I tried to use onResume and onPause methods in activities to know when the app goes in background and it is then resumed, but as only one activity can be alive at at time, I had no success. When an activity is paused, this doesn't mean that the app went to background, because another activity could have been launched, but the onResume event of that activity will trigger only after the previous one has paused.
I've also tried to list all the apps in foreground, but with no success, if I put my app in background resuming another app, my app always results to be in the foreground.
I read that since Android 4 there is a new method to know when the app is in foreground, but I need my app to be compatible with Android 3.0 devices too.
Here is the code I tried putting in every single activity (MyApp is my Application name):
#Override
protected void onResume() {
super.onResume();
MyApp.isPaused = false;
}
#Override
protected void onPause() {
super.onPause();
MyApp.isPaused = true;
}
This is also my attempt to list all the apps in foreground:
ActivityManager activityManager = (ActivityManager)((Activity) currentContext).getSystemService( ACTIVITY_SERVICE );
List<RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
for(RunningAppProcessInfo appProcess : appProcesses){
if(appProcess.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND){
if(appProcess.processName.equals("com.xxx.myapp")) {
Log.i("MyApp", "it's in foreground");
}
Log.i("MyApp", appProcess.processName);
}
}

This class provides a singleton to determine "the activity in background" status. It uses a timer with a threshold(i.e. 0.3s) to determine the activity is went to background or not.
One thing has to point out is that if the user resumes to the activity within the threshold (i.e. 0.3s), this test will be failed.
If you have a better solution, please share with us :)
Ref: https://gist.github.com/steveliles/11116937

You are absolutely correct :) Because only one activity can be alive at a time so you need something which remains alive through out the application life cycle :) like Application instance itself or you can also make use of shared preference for that matter. But seriously using shared prefference for checking lifecycle is wrong choice if you ask me.
If I was in your position I would have gone for Application class :) Here is code if you want to do the same :)
import android.app.Application;
/**
* Created by sandeepbhandari on 3/3/16.
*/
public class AppService extends Application{
private static AppService sInstance;
public static boolean isGoingToBackGround=false;
#Override
public void onCreate() {
super.onCreate();
sInstance = this;
}
public static AppService getInstance() {
return sInstance;
}
}
In all your activities onPause just set
AppService service = AppService.getInstance();
service.isGoingToBackGround =true;
And in onResume check the same variablethats all :) and yeah if you want to use your application class rather than default Application you have to make change to manifest.xml
<application
android:name=".AppService"
Thats all :)

Override onTrimMemory(int level) in your Application. Might not be the prettiest way, but it has worked for me.
You will get
TRIM_MEMORY_BACKGROUND = 40;
when your application went into the Background.

You can make Application class inside your project to save state of your project. When any activity goes to pause call on pause respectively while on resume call on resume method and save state of the inside this class. Even if one activity goes on pause another on resume your class will know exact state of the application. Or another way you can save applicaton state in shared preference in each activity can change its value.

i trust there is no need for u to post a code... that being said...
start by logging every implemented methods onCreate(), onPause(), onDestroy(), and other well reputed Activity methods...
but back button does not just pause it kills, thus onCreate is called most
and check onStart() too.

public class CustomApplication extends Application {
private static boolean activityVisible;
#Override
public void onCreate() {
super.onCreate();
}
public static boolean isActivityVisible() {
return activityVisible;
}
public static void activityResumed() {
activityVisible = true;
}
public static void activityPaused() {
activityVisible = false;
}
}
and in your all activities set
#Override
protected void onResume() {
super.onResume();
CustomApplication.activityResumed();
}
#Override
protected void onPause() {
super.onPause();
CustomApplication.activityPaused();
}
and in your manifest
<application
android:name=".CustomApplication"

Android - Display notification when application is in background

I am using AlarmManager to periodically check for new content at some endpoint, validate if the results coming from the endpoint are the same as the ones I already have on my app, and if its not the same create a notification for each item.
What i need to know is how should i make the alarms to start only when the application is paused or stopped and cancel the alarms when de application is started or resumed.
where should i start the alarms and where should i cancel them?
In Android Notifications Guideline it says (on chapter: When not to display a notification):
Don't create a notification if the relevant new information is currently on screen. Instead, use the UI of the application itself to notify the user of new information directly in context. For instance, a chat application should not create system notifications while the user is actively chatting with another user.
If I have the application open i just want to disable alarms, when the application is closed/paused i want to cancel everything.

You need to create a Custom Application with global state and implement your own onPause and onResume at Application Level.
Create your own subclass of Application like this:
public class MyApplication extends Application {
private static MyApplication sInstance;
public MyApplication getInstance(){
return sInstance;
}
#Override
public void onCreate() {
super.onCreate();
sInstance = this;
}
public void onStart() {
// TODO: Stop your notification.
}
public void onStop() {
// TODO: Start your notification.
}
}
Specify its name in your AndroidManifest.xml's tag:
<application
android:icon="#drawable/icon"
android:label="#string/app_name"
android:name="MyApplication">
Create a class to hold the counts of activities:
public class ActiveActivitiesTracker {
private static int sActiveActivities = 0;
public static void activityStarted()
{
if (sActiveActivities == 0) {
// TODO: Here is presumably "application level" resume
MyApplication.getInstance().onStart();
}
sActiveActivities++;
}
public static void activityStopped()
{
sActiveActivities--;
if (sActiveActivities == 0) {
// TODO: Here is presumably "application level" pause
MyApplication.getInstance().onStop();
}
}
}
Then create a base activity (or do that in every activity), simply call the activityStarted() and activityStopped() methods:
#Override
public void onStart() {
super.onStart();
ActiveActivitiesTracker.activityStarted();
}
#Override
public void onStop() {
super.onStop();
ActiveActivitiesTracker.activityStopped();
}
For more details about Custom Application, see this.
For more details about Android Application Level Pause and Resume, see this.
Hope this helps.

you can try using a service and override in it , the onTrimMemory method and show the notificaton when "level" is equal to TRIM_MEMORY_UI_HIDDEN
#Override
public void onTrimMemory(int level) {
super.onTrimMemory(level);
switch (level) {
case ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN:
break;
}
}
check the documentation for more info
http://developer.android.com/reference/android/content/ComponentCallbacks2.html#TRIM_MEMORY_UI_HIDDEN

I am not sure that this will be feasible within your project or if it will achieve what you hope to, however you could extend all of your activities from one base activity. In that base activity's onPause/onStop/onDestroy methods start the alarms and in that base activities onCreate/onStart methods cancel the alarms with the pending intent.
This will provide you with a set location from which you can handle your alarms if you have multiple activities from which the app may close.
You can learn more about the life cycle of activities here.

Checking if an Android application is running in the background

By background, I mean none of the application's activities are currently visible to the user?

There are few ways to detect whether your application is running in the background, but only one of them is completely reliable:
The right solution (credits go to Dan, CommonsWare and NeTeInStEiN)
Track visibility of your application by yourself using Activity.onPause, Activity.onResume methods. Store "visibility" status in some other class. Good choices are your own implementation of the Application or a Service (there are also a few variations of this solution if you'd like to check activity visibility from the service).
Example
Implement custom Application class (note the isActivityVisible() static method):
public class MyApplication extends Application {
public static boolean isActivityVisible() {
return activityVisible;
}
public static void activityResumed() {
activityVisible = true;
}
public static void activityPaused() {
activityVisible = false;
}
private static boolean activityVisible;
}
Register your application class in AndroidManifest.xml:
<application
android:name="your.app.package.MyApplication"
android:icon="#drawable/icon"
android:label="#string/app_name" >
Add onPause and onResume to every Activity in the project (you may create a common ancestor for your Activities if you'd like to, but if your activity is already extended from MapActivity/ListActivity etc. you still need to write the following by hand):
#Override
protected void onResume() {
super.onResume();
MyApplication.activityResumed();
}
#Override
protected void onPause() {
super.onPause();
MyApplication.activityPaused();
}
Update
ActivityLifecycleCallbacks were added in API level 14 (Android 4.0). You can use them to track whether an activity of your application is currently visible to the user. Check Cornstalks' answer below for the details.
The wrong one
I used to suggest the following solution:
You can detect currently foreground/background application with ActivityManager.getRunningAppProcesses() which returns a list of RunningAppProcessInfo records. To determine if your application is on the foreground check RunningAppProcessInfo.importance field for equality to RunningAppProcessInfo.IMPORTANCE_FOREGROUND while RunningAppProcessInfo.processName is equal to your application package name.
Also if you call ActivityManager.getRunningAppProcesses() from your application UI thread it will return importance IMPORTANCE_FOREGROUND for your task no matter whether it is actually in the foreground or not. Call it in the background thread (for example via AsyncTask) and it will return correct results.
While this solution may work (and it indeed works most of the time) I strongly recommend to refrain from using it. And here's why. As Dianne Hackborn wrote:
These APIs are not there for applications to base their UI flow on, but to do things like show the user the running apps, or a task manager, or such.
Yes there is a list kept in memory for these things. However, it is off in another process, managed by threads running separately from yours, and not something you can count on (a) seeing in time to make the correct decision or (b) have a consistent picture by the time you return. Plus the decision about what the "next" activity to go to is always done at the point where the switch is to happen, and it is not until that exact point (where the activity state is briefly locked down to do the switch) that we actually know for sure what the next thing will be.
And the implementation and global behavior here is not guaranteed to remain the same in the future.
I wish I had read this before I posted an answer on the SO, but hopefully it's not too late to admit my error.
Another wrong solution
Droid-Fu library mentioned in one of the answers uses ActivityManager.getRunningTasks for its isApplicationBroughtToBackground method. See Dianne's comment above and don't use that method either.

GOOGLE SOLUTION - not a hack, like previous solutions. Use ProcessLifecycleOwnerKotlin:
class ArchLifecycleApp : Application(), LifecycleObserver {
override fun onCreate() {
super.onCreate()
ProcessLifecycleOwner.get().lifecycle.addObserver(this)
}
#OnLifecycleEvent(Lifecycle.Event.ON_STOP)
fun onAppBackgrounded() {
//App in background
}
#OnLifecycleEvent(Lifecycle.Event.ON_START)
fun onAppForegrounded() {
// App in foreground
}
}
Java:
public class ArchLifecycleApp extends Application implements LifecycleObserver {
#Override
public void onCreate() {
super.onCreate();
ProcessLifecycleOwner.get().getLifecycle().addObserver(this);
}
#OnLifecycleEvent(Lifecycle.Event.ON_STOP)
public void onAppBackgrounded() {
//App in background
}
#OnLifecycleEvent(Lifecycle.Event.ON_START)
public void onAppForegrounded() {
// App in foreground
}
}
in app.gradle
dependencies {
...
implementation "android.arch.lifecycle:extensions:1.1.0"
//New Android X dependency is this -
implementation "androidx.lifecycle:lifecycle-extensions:2.0.0"
}
allprojects {
repositories {
...
google()
jcenter()
maven { url 'https://maven.google.com' }
}
}
You can read more about Lifecycle related architecture components here - https://developer.android.com/topic/libraries/architecture/lifecycle

DO NOT USE THIS ANSWER
user1269737's answer is the proper (Google/Android approved) way to do this. Go read their answer and give them a +1.
I'll leave my original answer here for posterity's sake. This was the best available back in 2012, but now Android has proper support for this.
Original answer
The key is using ActivityLifecycleCallbacks (note that this requires Android API level 14 (Android 4.0)). Just check if the number of stopped activities is equal to the number of started activities. If they're equal, your application is being backgrounded. If there are more started activities, your application is still visible. If there are more resumed than paused activities, your application is not only visible, but it's also in the foreground. There are 3 main states that your activity can be in, then: visible and in the foreground, visible but not in the foreground, and not visible and not in the foreground (i.e. in the background).
The really nice thing about this method is that it doesn't have the asynchronous issues getRunningTasks() does, but you also don't have to modify every Activity in your application to set/unset something in onResumed()/onPaused(). It's just a few lines of code that's self contained, and it works throughout your whole application. Plus, there are no funky permissions required either.
MyLifecycleHandler.java:
public class MyLifecycleHandler implements ActivityLifecycleCallbacks {
// I use four separate variables here. You can, of course, just use two and
// increment/decrement them instead of using four and incrementing them all.
private int resumed;
private int paused;
private int started;
private int stopped;
#Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
}
#Override
public void onActivityDestroyed(Activity activity) {
}
#Override
public void onActivityResumed(Activity activity) {
++resumed;
}
#Override
public void onActivityPaused(Activity activity) {
++paused;
android.util.Log.w("test", "application is in foreground: " + (resumed > paused));
}
#Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
}
#Override
public void onActivityStarted(Activity activity) {
++started;
}
#Override
public void onActivityStopped(Activity activity) {
++stopped;
android.util.Log.w("test", "application is visible: " + (started > stopped));
}
// If you want a static function you can use to check if your application is
// foreground/background, you can use the following:
/*
// Replace the four variables above with these four
private static int resumed;
private static int paused;
private static int started;
private static int stopped;
// And these two public static functions
public static boolean isApplicationVisible() {
return started > stopped;
}
public static boolean isApplicationInForeground() {
return resumed > paused;
}
*/
}
MyApplication.java:
// Don't forget to add it to your manifest by doing
// <application android:name="your.package.MyApplication" ...
public class MyApplication extends Application {
#Override
public void onCreate() {
// Simply add the handler, and that's it! No need to add any code
// to every activity. Everything is contained in MyLifecycleHandler
// with just a few lines of code. Now *that's* nice.
registerActivityLifecycleCallbacks(new MyLifecycleHandler());
}
}
#Mewzer has asked some good questions about this method that I'd like to respond to in this answer for everyone:
onStop() is not called in low memory situations; is that a problem here?
No. The docs for onStop() say:
Note that this method may never be called, in low memory situations where the system does not have enough memory to keep your activity's process running after its onPause() method is called.
The key here is "keep your activity's process running..." If this low memory situation is ever reached, your process is actually killed (not just your activity). This means that this method of checking for backgrounded-ness is still valid because a) you can't check for backgrounding anyway if your process is killed, and b) if your process starts again (because a new activity is created), the member variables (whether static or not) for MyLifecycleHandler will be reset to 0.
Does this work for configuration changes?
By default, no. You have to explicitly set configChanges=orientation|screensize (| with anything else you want) in your manifest file and handle the configuration changes, or else your activity will be destroyed and recreated. If you do not set this, your activity's methods will be called in this order: onCreate -> onStart -> onResume -> (now rotate) -> onPause -> onStop -> onDestroy -> onCreate -> onStart -> onResume. As you can see, there is no overlap (normally, two activities overlap very briefly when switching between the two, which is how this backgrounding-detection method works). In order to get around this, you must set configChanges so that your activity is not destroyed. Fortunately, I've had to set configChanges already in all of my projects because it was undesirable for my entire activity to get destroyed on screen rotate/resize, so I've never found this to be problematic. (thanks to dpimka for refreshing my memory on this and correcting me!)
One note:
When I've said "background" here in this answer, I've meant "your app is no longer visible." Android activities can be visible yet not in the foreground (for example, if there's a transparent notification overlay). That's why I've updated this answer to reflect that.
It's important to know that Android has a weird limbo moment when switching activities where nothing is in the foreground. For this reason, if you check if your application is in the foreground when switching between activities (in the same app), you'll be told you're not in the foreground (even though your app is still the active app and is visible).
You can check if your app is in the foreground in your Activity's onPause() method after super.onPause(). Just remember the weird limbo state I just talked about.
You can check if your app is visible (i.e. if it's not in the background) in your Activity's onStop() method after super.onStop().

Starting support library version 26 you can use ProcessLifecycleOwner, just add it to your dependency like described here, for example:
dependencies {
def lifecycle_version = "1.1.1"
// ViewModel and LiveData
implementation "android.arch.lifecycle:extensions:$lifecycle_version"
// alternatively - Lifecycles only (no ViewModel or LiveData).
// Support library depends on this lightweight import
implementation "android.arch.lifecycle:runtime:$lifecycle_version"
annotationProcessor "android.arch.lifecycle:compiler:$lifecycle_version" // use kapt for Kotlin
}
And then just query ProcessLifecycleOwner whenever you want for app state, examples:
// Check if app is in background
ProcessLifecycleOwner.get().getLifecycle().getCurrentState() == Lifecycle.State.CREATED;
// Check if app is in foreground
ProcessLifecycleOwner.get().getLifecycle().getCurrentState().isAtLeast(Lifecycle.State.STARTED);

Since Android API 16 there is a simple way to check if app is in foreground. It may not be foolproof, but no methods on Android are foolproof. This method is good enough to use when your service receives update from server and has to decide whether to show notification, or not (because if UI is foreground, user will notice the update without notification).
RunningAppProcessInfo myProcess = new RunningAppProcessInfo();
ActivityManager.getMyMemoryState(myProcess);
isInBackground = myProcess.importance != RunningAppProcessInfo.IMPORTANCE_FOREGROUND;

Idolon's answer is error prone and much more complicated althought repeatead here check android application is in foreground or not? and here Determining the current foreground application from a background task or service
There is a much more simpler approach:
On a BaseActivity that all Activities extend:
protected static boolean isVisible = false;
#Override
public void onResume()
{
super.onResume();
setVisible(true);
}
#Override
public void onPause()
{
super.onPause();
setVisible(false);
}
Whenever you need to check if any of your application activities is in foreground just check isVisible();
To understand this approach check this answer of side-by-side activity lifecycle: Activity side-by-side lifecycle

I tried the recommended solution that uses Application.ActivityLifecycleCallbacks and many others, but they didn't work as expected. Thanks to Sarge, I came up with a pretty easy and straightforward solution that I am describing below.
They key of the solution is the fact of understanding that if we have ActivityA and ActivityB, and we call ActivityB from ActivityA (and not call ActivityA.finish), then ActivityB's onStart() will be called before ActivityA onStop().
That's also the main difference between onStop() and onPause() that none did mention in the articles I read.
So based on this Activity's Lifecycle behavior, you can simply count how many times did onStart() and onPause() got called in your program. Note that for each Activity of your program, you must override onStart() and onStop(), in order to increment/decrement the static variable used for counting. Below is the code implementing this logic. Note that I am using a class that extends Application, so dont forget to declare on Manifest.xml inside Application tag: android:name=".Utilities", although it can be implemented using a simple custom class too.
public class Utilities extends Application
{
private static int stateCounter;
public void onCreate()
{
super.onCreate();
stateCounter = 0;
}
/**
* #return true if application is on background
* */
public static boolean isApplicationOnBackground()
{
return stateCounter == 0;
}
//to be called on each Activity onStart()
public static void activityStarted()
{
stateCounter++;
}
//to be called on each Activity onStop()
public static void activityStopped()
{
stateCounter--;
}
}
Now on each Activity of our program, we should override onStart() and onStop() and increment/decrement as shown below:
#Override
public void onStart()
{
super.onStart();
Utilities.activityStarted();
}
#Override
public void onStop()
{
Utilities.activityStopped();
if(Utilities.isApplicationOnBackground())
{
//you should want to check here if your application is on background
}
super.onStop();
}
With this logic, there are 2 possible cases:
stateCounter = 0 : The number of stopped is equal with the number of started Activities, which means that the application is running on the background.
stateCounter > 0 : The number of started is bigger than the number of stopped, which means that the application is running on the foreground.
Notice: stateCounter < 0 would mean that there are more stopped Activities rather than started, which is impossible. If you encounter this case, then it means that you are not increasing/decreasing the counter as you should.
You are ready to go. You should want to check if your application is on background inside onStop().

There is no way, short of you tracking it yourself, to determine if any of your activities are visible or not. Perhaps you should consider asking a new StackOverflow question, explaining what it is you are trying to achieve from a user experience, so we can perhaps give you alternative implementation ideas.

You can use ComponentCallbacks2 to detect if the app is in background. BTW this callback is only available in API Level 14 (Ice Cream Sandwich) and above.
You will get a call to the method:
public abstract void onTrimMemory (int level)
if the level is ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN then the app is in background.
You can implement this interface to an activity, service, etc.
public class MainActivity extends AppCompatActivity implements ComponentCallbacks2 {
#Override
public void onConfigurationChanged(final Configuration newConfig) {
}
#Override
public void onLowMemory() {
}
#Override
public void onTrimMemory(final int level) {
if (level == ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN) {
// app is in background
}
}
}

Building on #Cornstalks answer to include a couple of useful features.
Extra features:
introduced singleton pattern so you can do this anywhere in the application: AppLifecycleHandler.isApplicationVisible() and AppLifecycleHandler.isApplicationInForeground()
added handling of duplicate events (see comments // take some action on change of visibility and // take some action on change of in foreground)
App.java
public class App extends Application {
#Override
public void onCreate() {
super.onCreate();
registerActivityLifecycleCallbacks(AppLifecycleHandler.getInstance());
}
}
AppLifecycleHandler.java
public class AppLifecycleHandler implements Application.ActivityLifecycleCallbacks {
private int resumed;
private int started;
private final String DebugName = "AppLifecycleHandler";
private boolean isVisible = false;
private boolean isInForeground = false;
private static AppLifecycleHandler instance;
public static AppLifecycleHandler getInstance() {
if (instance == null) {
instance = new AppLifecycleHandler();
}
return instance;
}
private AppLifecycleHandler() {
}
#Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
}
#Override
public void onActivityDestroyed(Activity activity) {
}
#Override
public void onActivityResumed(Activity activity) {
++resumed;
android.util.Log.w(DebugName, "onActivityResumed -> application is in foreground: " + (resumed > 0) + " (" + activity.getClass() + ")");
setForeground((resumed > 0));
}
#Override
public void onActivityPaused(Activity activity) {
--resumed;
android.util.Log.w(DebugName, "onActivityPaused -> application is in foreground: " + (resumed > 0) + " (" + activity.getClass() + ")");
setForeground((resumed > 0));
}
#Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
}
#Override
public void onActivityStarted(Activity activity) {
++started;
android.util.Log.w(DebugName, "onActivityStarted -> application is visible: " + (started > 0) + " (" + activity.getClass() + ")");
setVisible((started > 0));
}
#Override
public void onActivityStopped(Activity activity) {
--started;
android.util.Log.w(DebugName, "onActivityStopped -> application is visible: " + (started > 0) + " (" + activity.getClass() + ")");
setVisible((started > 0));
}
private void setVisible(boolean visible) {
if (isVisible == visible) {
// no change
return;
}
// visibility changed
isVisible = visible;
android.util.Log.w(DebugName, "App Visiblility Changed -> application is visible: " + isVisible);
// take some action on change of visibility
}
private void setForeground(boolean inForeground) {
if (isInForeground == inForeground) {
// no change
return;
}
// in foreground changed
isInForeground = inForeground;
android.util.Log.w(DebugName, "App In Foreground Changed -> application is in foreground: " + isInForeground);
// take some action on change of in foreground
}
public static boolean isApplicationVisible() {
return AppLifecycleHandler.getInstance().started > 0;
}
public static boolean isApplicationInForeground() {
return AppLifecycleHandler.getInstance().resumed > 0;
}
}

The best solution I have come up with uses timers.
You have start a timer in onPause() and cancel the same timer in onResume(), there is 1 instance of the Timer (usually defined in the Application class). The timer itself is set to run a Runnable after 2 seconds (or whatever interval you think is appropriate), when the timer fires you set a flag marking the application as being in the background.
In the onResume() method before you cancel the timer, you can query the background flag to perform any startup operations (e.g. start downloads or enable location services).
This solution allows you to have several activities on the back stack, and doesn't require any permissions to implement.
This solution works well if you use an event bus too, as your timer can simply fire an event and various parts of your app can respond accordingly.

If you turn on developer settings "Don't keep actvities" - check only count of created activites is not enough. You must check also isSaveInstanceState. My custom method isApplicationRunning() check is android app is running:
Here my work code:
public class AppLifecycleService implements Application.ActivityLifecycleCallbacks {
private int created;
private boolean isSaveInstanceState;
private static AppLifecycleService instance;
private final static String TAG = AppLifecycleService.class.getName();
public static AppLifecycleService getInstance() {
if (instance == null) {
instance = new AppLifecycleService();
}
return instance;
}
public static boolean isApplicationRunning() {
boolean isApplicationRunning = true;
if (getCountCreatedActvities() == 0 && !isSaveInstanceState()) {
isApplicationRunning = false;
}
return isApplicationRunning;
}
public static boolean isSaveInstanceState() {
return AppLifecycleService.getInstance().isSaveInstanceState;
}
public static int getCountCreatedActvities() {
return AppLifecycleService.getInstance().created;
}
private AppLifecycleService() {
}
#Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
this.isSaveInstanceState = true;
}
#Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
++created;
}
#Override
public void onActivityDestroyed(Activity activity) {
--created;
}
#Override
public void onActivityResumed(Activity activity) { }
#Override
public void onActivityPaused(Activity activity) { }
#Override
public void onActivityStarted(Activity activity) { }
#Override
public void onActivityStopped(Activity activity) { }
}

To piggyback on what CommonsWare and Key have said, you could perhaps extend the Application class and have all of your activities call that on their onPause/onResume methods. This would allow you to know which Activity(ies) are visible, but this could probably be handled better.
Can you elaborate on what you have in mind exactly? When you say running in the background do you mean simply having your application still in memory even though it is not currently on screen? Have you looked into using Services as a more persistent way to manage your app when it is not in focus?

I did my own implementation of ActivityLifecycleCallbacks. I'm using SherlockActivity, but for normal Activity class might work.
First, I'm creating an interface that have all methods for track the activities lifecycle:
public interface ActivityLifecycleCallbacks{
public void onActivityStopped(Activity activity);
public void onActivityStarted(Activity activity);
public void onActivitySaveInstanceState(Activity activity, Bundle outState);
public void onActivityResumed(Activity activity);
public void onActivityPaused(Activity activity);
public void onActivityDestroyed(Activity activity);
public void onActivityCreated(Activity activity, Bundle savedInstanceState);
}
Second, I implemented this interface in my Application's class:
public class MyApplication extends Application implements my.package.ActivityLifecycleCallbacks{
#Override
public void onCreate() {
super.onCreate();
}
#Override
public void onActivityStopped(Activity activity) {
Log.i("Tracking Activity Stopped", activity.getLocalClassName());
}
#Override
public void onActivityStarted(Activity activity) {
Log.i("Tracking Activity Started", activity.getLocalClassName());
}
#Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
Log.i("Tracking Activity SaveInstanceState", activity.getLocalClassName());
}
#Override
public void onActivityResumed(Activity activity) {
Log.i("Tracking Activity Resumed", activity.getLocalClassName());
}
#Override
public void onActivityPaused(Activity activity) {
Log.i("Tracking Activity Paused", activity.getLocalClassName());
}
#Override
public void onActivityDestroyed(Activity activity) {
Log.i("Tracking Activity Destroyed", activity.getLocalClassName());
}
#Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
Log.i("Tracking Activity Created", activity.getLocalClassName());
}
}
Third, I'm creating a class that extends from SherlockActivity:
public class MySherlockActivity extends SherlockActivity {
protected MyApplication nMyApplication;
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
nMyApplication = (MyApplication) getApplication();
nMyApplication.onActivityCreated(this, savedInstanceState);
}
protected void onResume() {
// TODO Auto-generated method stub
nMyApplication.onActivityResumed(this);
super.onResume();
}
#Override
protected void onPause() {
// TODO Auto-generated method stub
nMyApplication.onActivityPaused(this);
super.onPause();
}
#Override
protected void onDestroy() {
// TODO Auto-generated method stub
nMyApplication.onActivityDestroyed(this);
super.onDestroy();
}
#Override
protected void onStart() {
nMyApplication.onActivityStarted(this);
super.onStart();
}
#Override
protected void onStop() {
nMyApplication.onActivityStopped(this);
super.onStop();
}
#Override
protected void onSaveInstanceState(Bundle outState) {
nMyApplication.onActivitySaveInstanceState(this, outState);
super.onSaveInstanceState(outState);
}
}
Fourth, all class that extend from SherlockActivity, I replaced for MySherlockActivity:
public class MainActivity extends MySherlockActivity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
Now, in the logcat you will see the logs programmed in the Interface implementation made in MyApplication.

Offical docs:
The system distinguishes between foreground and background apps. (The definition of background for purposes of service limitations is distinct from the definition used by memory management; an app might be in the background as pertains to memory management, but in the foreground as pertains to its ability to launch services.) An app is considered to be in the foreground if any of the following is true:
It has a visible activity, whether the activity is started or paused.
It has a foreground service.
Another foreground app is connected to the app, either by binding to one of its services or by making use of one of its content providers. For example, the app is in the foreground if another app binds to its:
IME
Wallpaper service
Notification listener
Voice or text service
If none of those conditions is true, the app is considered to be in the background.

The only one correct solution:
MainActivity.java:
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
MyApp.mainActivity = this;
super.onCreate(savedInstanceState);
...
}
MyApp.java:
public class MyApp extends Application implements LifecycleObserver {
public static MainActivity mainActivity = null;
#Override
public void onCreate() {
super.onCreate();
ProcessLifecycleOwner.get().getLifecycle().addObserver(this);
}
#OnLifecycleEvent(Lifecycle.Event.ON_STOP)
void onAppBackgrounded() {
// app in background
if (mainActivity != null) {
...
}
}
#OnLifecycleEvent(Lifecycle.Event.ON_START)
void onAppForegrounded() {
// app in foreground
if (mainActivity != null) {
...
}
}
}

No any solution work for me, however I propose a raw solution. This should work. If isAppBackground return false, then app must be in foreground.
public static boolean isAppBackground(Context context){
boolean isBackground=true;
ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
if(Build.VERSION.SDK_INT > Build.VERSION_CODES.KITKAT_WATCH){
List<ActivityManager.RunningAppProcessInfo> runningProcesses =activityManager.getRunningAppProcesses();
for(ActivityManager.RunningAppProcessInfo processInfo:runningProcesses){
if(processInfo.importance==ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND){
for(String activeProcess:processInfo.pkgList){
if(activeProcess.equals(context.getPackageName())){
isBackground = false;
}
}
}
}
}else{
List<ActivityManager.RunningTaskInfo> taskInfo = activityManager.getRunningTasks(1);
if(taskInfo.size()>0) {
ComponentName componentName = taskInfo.get(0).topActivity;
if(componentName.getPackageName().equals(context.getPackageName())){
isBackground = false;
}
}
}
return isBackground;
}

Activity gets paused when a Dialog comes above it so all the recommended solutions are half-solutions. You need to create hooks for dialogs as well.

I recommend reading through this page: http://developer.android.com/reference/android/app/Activity.html
In short, your activity is no longer visible after onStop() has been called.

Since it isn't already mentioned, I will suggest the readers to explore ProcessLifecycleOwner available through Android Architecture components

This code will check foreground and background in any condition:
Java Code:
private static boolean isApplicationForeground(Context context) {
KeyguardManager keyguardManager =
(KeyguardManager) context.getSystemService(Context.KEYGUARD_SERVICE);
if (keyguardManager.isKeyguardLocked()) {
return false;
}
int myPid = Process.myPid();
ActivityManager activityManager =
(ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> list;
if ((list = activityManager.getRunningAppProcesses()) != null) {
for (ActivityManager.RunningAppProcessInfo aList : list) {
ActivityManager.RunningAppProcessInfo info;
if ((info = aList).pid == myPid) {
return info.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND;
}
}
}
return false;
}
Kotlin Code:
private fun isApplicationForeground(context: Context): Boolean {
val keyguardManager = context.getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager
if (keyguardManager.isKeyguardLocked) {
return false
}
val myPid = Process.myPid()
val activityManager = context.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
var list: List<ActivityManager.RunningAppProcessInfo>
if (activityManager.runningAppProcesses.also { list = it } != null) {
for (aList in list) {
var info: ActivityManager.RunningAppProcessInfo
if (aList.also { info = it }.pid == myPid) {
return info.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND
}
}
}
return false
}

Simple and straight-forward answer:
override fun onPause() {
Log.i("APP LIFECYCLE", "App Enter BACKground")
isForeground = false
super.onPause()
}
override fun onResume() {
Log.i("APP LIFECYCLE", "App Enter FOREground")
isForeground = true
super.onResume()
}
Then just use the isForeground property of your activity to check the status.

Another solution for this old post (for those that it might help) :
<application android:name=".BaseApplication" ... >
public class BaseApplication extends Application {
private class Status {
public boolean isVisible = true;
public boolean isFocused = true;
}
private Map<Activity, Status> activities;
#Override
public void onCreate() {
activities = new HashMap<Activity, Status>();
super.onCreate();
}
private boolean hasVisibleActivity() {
for (Status status : activities.values())
if (status.isVisible)
return true;
return false;
}
private boolean hasFocusedActivity() {
for (Status status : activities.values())
if (status.isFocused)
return true;
return false;
}
public void onActivityCreate(Activity activity, boolean isStarting) {
if (isStarting && activities.isEmpty())
onApplicationStart();
activities.put(activity, new Status());
}
public void onActivityStart(Activity activity) {
if (!hasVisibleActivity() && !hasFocusedActivity())
onApplicationForeground();
activities.get(activity).isVisible = true;
}
public void onActivityWindowFocusChanged(Activity activity, boolean hasFocus) {
activities.get(activity).isFocused = hasFocus;
}
public void onActivityStop(Activity activity, boolean isFinishing) {
activities.get(activity).isVisible = false;
if (!isFinishing && !hasVisibleActivity() && !hasFocusedActivity())
onApplicationBackground();
}
public void onActivityDestroy(Activity activity, boolean isFinishing) {
activities.remove(activity);
if(isFinishing && activities.isEmpty())
onApplicationStop();
}
private void onApplicationStart() {Log.i(null, "Start");}
private void onApplicationBackground() {Log.i(null, "Background");}
private void onApplicationForeground() {Log.i(null, "Foreground");}
private void onApplicationStop() {Log.i(null, "Stop");}
}
public class MyActivity extends BaseActivity {...}
public class BaseActivity extends Activity {
private BaseApplication application;
#Override
protected void onCreate(Bundle state) {
application = (BaseApplication) getApplication();
application.onActivityCreate(this, state == null);
super.onCreate(state);
}
#Override
protected void onStart() {
application.onActivityStart(this);
super.onStart();
}
#Override
public void onWindowFocusChanged(boolean hasFocus) {
application.onActivityWindowFocusChanged(this, hasFocus);
super.onWindowFocusChanged(hasFocus);
}
#Override
protected void onStop() {
application.onActivityStop(this, isFinishing());
super.onStop();
}
#Override
protected void onDestroy() {
application.onActivityDestroy(this, isFinishing());
super.onDestroy();
}
}

See the comment in the onActivityDestroyed function.
Works with SDK target version 14> :
import android.app.Activity;
import android.app.Application;
import android.os.Bundle;
import android.util.Log;
public class AppLifecycleHandler implements Application.ActivityLifecycleCallbacks {
public static int active = 0;
#Override
public void onActivityStopped(Activity activity) {
Log.i("Tracking Activity Stopped", activity.getLocalClassName());
active--;
}
#Override
public void onActivityStarted(Activity activity) {
Log.i("Tracking Activity Started", activity.getLocalClassName());
active++;
}
#Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
Log.i("Tracking Activity SaveInstanceState", activity.getLocalClassName());
}
#Override
public void onActivityResumed(Activity activity) {
Log.i("Tracking Activity Resumed", activity.getLocalClassName());
active++;
}
#Override
public void onActivityPaused(Activity activity) {
Log.i("Tracking Activity Paused", activity.getLocalClassName());
active--;
}
#Override
public void onActivityDestroyed(Activity activity) {
Log.i("Tracking Activity Destroyed", activity.getLocalClassName());
active--;
// if active var here ever becomes zero, the app is closed or in background
if(active == 0){
...
}
}
#Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
Log.i("Tracking Activity Created", activity.getLocalClassName());
active++;
}
}

You should use a shared preference to store the property and act upon it using service binding from your activities. If you use binding only, (that is never use startService), then your service would run only when you bind to it, (bind onResume and unbind onPause) that would make it run on foreground only, and if you do want to work on background you can use the regular start stop service.

I think this question should be more clear. When? Where? What is your specific situation you want to konw if your app is in background?
I just introduce my solution in my way.
I get this done by using the field "importance" of RunningAppProcessInfo class in every activity's onStop method in my app, which can be simply achieved by providing a BaseActivity for other activities to extend which implements the onStop method to check the value of "importance". Here is the code:
public static boolean isAppRunning(Context context) {
ActivityManager activityManager = (ActivityManager) context
.getSystemService(Context.ACTIVITY_SERVICE);
List<RunningAppProcessInfo> appProcesses = activityManager
.getRunningAppProcesses();
for (RunningAppProcessInfo appProcess : appProcesses) {
if (appProcess.processName.equals(context.getPackageName())) {
if (appProcess.importance != RunningAppProcessInfo.IMPORTANCE_PERCEPTIBLE) {
return true;
}
}
}
return false;
}

What about using getApplicationState().isInForeground() ?

In my opinion, many answers introduce a heavy load of code and bring lots of complexity and non-readability.
When people ask on SO how to communicate between a Service and a Activity, I usually advice to use the LocalBroadcastManager.
Why?
Well, by quoting the docs:
You know that the data you are broadcasting won't leave your app, so don't need to worry about leaking private data.
It is not possible for other applications to send these broadcasts to your app, so you don't need to worry about having security holes they can exploit.
It is more efficient than sending a global broadcast through the system.
Not in the the docs:
It does not require external libraries
The code is minimal
It's fast to implement and understand
No custom self-implemented callbacks / ultra-singleton / intra-process
pattern whatsoever...
No strong references on Activity, Application, ...
Description
So, you want to check if any of the Activity is currently in the foreground. You usually do that in a Service, or your Application class.
This means, your Activity objects become the sender of a signal (I'm on / I'm off). Your Service, on the other hand, becomes the Receiver.
There are two moments in which your Activity tells you if it's going in the foreground or in the background (yes only two... not 6).
When the Activity goes into the foreground, the onResume() method is triggered (also called after onCreate()).
When the Activity goes in the back, onPause() is called.
These are the moments in which your Activity should send the signal to your Service to describe its state.
In case of multiple Activity's, remember the an Activity goes into the background first, then another one comes into the foreground.
So the situation would be:*
Activity1 -- send --> Signal:OFF
Activity2 -- send --> Signal:ON
The Service / Application will simply keep listening for those signals and act accordingly.
Code (TLDR)
Your Service must implement a BroadcastReceiver in order to listen for signals.
this.localBroadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
// received data if Activity is on / off
}
}
public static final IntentFilter SIGNAL_FILTER = new IntentFilter("com.you.yourapp.MY_SIGNAL")
Register the Receiver in Service::onCreate()
#Override
protected void onCreate() {
LocalBroadcastManager.getInstance(getApplicationContext()).registerReceiver(this.localBroadcastReceiver, SIGNAL_FILTER);
}
Un-register it in Service::onDestroy()
#Override
protected void onDestroy() {
// I'm dead, no need to listen to anything anymore.
LocalBroadcastManager.getInstance(getApplicationContext()).unregisterReceiver(this.localBroadcastReceiver);
}
Now your Activity's must communicated their state.
In Activity::onResume()
Intent intent = new Intent();
intent.setAction(SomeActivity.SIGNAL_FILTER); // put ON boolean in intent
LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(intent);
In Activity::onPause()
Intent intent = new Intent();
intent.setAction(SomeActivity.SIGNAL_FILTER); // put OFF boolean in intent
LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(intent);
A very, very common situation
Developer: I want to send data from my Service and update the Activity. How do I check if the Activity is in the foreground?
There is usually no need to check if the Activity is in the foreground or not. Just send the data via LocalBroadcastManager from your Service. If the Activity is on, then it will respond and act.
For this very common situation, the Service becomes the sender, and the Activity implements the BroadcastReceiver.
So, create a Receiver in your Activity. Register it in onResume() and un-register it in onPause(). There is no need to use the other life-cycle methods.
Define the Receiver behavior in onReceive() (update ListView, do this, do that, ...).
This way the Activity will listen only if it's in the foreground and nothing will happen if it's in the back or is destroyed.
In case of multiple Activity's, whichever Activity is on will respond (if they also implement the Receiver).
If all are in the background, nobody will respond and the signal will simply get lost.
Send the data from the Service via Intent (see code above) by specifying the signal ID.
Except for Multi-Window Support. It may be tricky (please test it if needed)...

fun isAppInForeground(): Boolean {
val activityManager = getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager ?: return false
val appProcesses = activityManager.runningAppProcesses ?: return false
val packageName = packageName
for (appProcess in appProcesses) {
if (appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND && appProcess.processName == packageName) {
return true
}
}
return false
}

None of the answers quite fitted the specific case if you're looked to know if a specfic activity is in the forground and if you're an SDK without direct access to the Application. For me I was in background thread having just recieved a push notification for a new chat message and only want to display a system notification if the chat screen isn't in the foreground.
Using the ActivityLifecycleCallbacks that as been recommended in other answers I've created a small util class that houses the logic to whether MyActivity is in the Foreground or not.
class MyActivityMonitor(context: Context) : Application.ActivityLifecycleCallbacks {
private var isMyActivityInForeground = false
init {
(context.applicationContext as Application).registerActivityLifecycleCallbacks(this)
}
fun isMyActivityForeground() = isMyActivityInForeground
override fun onActivityPaused(activity: Activity?) {
if (activity is MyActivity) {
isMyActivityInForeground = false
}
}
override fun onActivityResumed(activity: Activity?) {
if (activity is MyActivity) {
isMyActivityInForeground = true
}
}
}