Android how do I check if activity is running

Question

Is there any simple way of determining whether or not a certain activity is active  I want to do certain things depending on which activity is active  eg    if activityrunning    activity1    do this else if  activityrunning    activity2    do something else

User · Answer

Far better way than using a static variable and following OOP  Shared Preferences can be used to share variables with other activities and services from one application      public class example extends Activity         Override     protected void onStart             super onStart                Store our shared preference         SharedPreferences sp   getSharedPreferences  OURINFO   MODE PRIVATE           Editor ed   sp edit            ed putBoolean  active   true           ed commit                Override     protected void onStop             super onStop                Store our shared preference         SharedPreferences sp   getSharedPreferences  OURINFO   MODE PRIVATE           Editor ed   sp edit            ed putBoolean  active   false           ed commit               Use shared preferences  It has the most reliable state information  less application switch destroy issues  saves us to ask for yet another permission and it gives us more control to decide when our activity is actually the topmost   see details here  abd here also

User · Answer

There is a much easier way than everything above and this approach does not require the use of android permission GET TASKS in the manifest  or have the issue of race conditions or memory leaks pointed out in the accepted answer    Make a STATIC variable in the main Activity  Static allows other activities to receive the data from another activity  onPause   set this variable false  onResume and onCreate   set this variable true   private static boolean mainActivityIsOpen   Assign getters and setters of this variable   public static boolean mainActivityIsOpen         return mainActivityIsOpen     public static void mainActivityIsOpen boolean mainActivityIsOpen        DayView mainActivityIsOpen   mainActivityIsOpen     And then from another activity or Service  if  MainActivity mainActivityIsOpen      false                      do something   else if MainActivity mainActivityIsOpen      true     or just else        or else if  does t matter            do something

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If you want to check if the activity is in the back stack just follow next steps  1  Declared an ArrayList in your Application class  Application class is defined in your mainfest file in application tag   private ArrayList lt Class gt  runningActivities   new ArrayList lt  gt        And add the following public methods to access and modify this list    public void addActivityToRunningActivityies  Class cls    if   runningActivities contains cls   runningActivities add cls      public void removeActivityFromRunningActivities  Class cls    if  runningActivities contains cls   runningActivities remove cls      public boolean isActivityInBackStack  Class cls    return runningActivities contains cls      In your BaseActivity  where all activities extend it  override onCreate and onDestroy methods so you can add and remove activities from back stack as the following    Override protected void onCreate  Nullable Bundle savedInstanceState    super onCreate savedInstanceState      MyApplicationClass getApplication    addActivityToRunningActivityies  this getClass         Override protected void onDestroy     super onDestroy       MyApplicationClass getApplication    removeActivityFromRunningActivities  this getClass        Finally if you want to check whether the activity is in the back stack or not just call this function isActivityInBackStack    Ex  I want to check if the HomeActivityis in the back stack or not   if    MyApplicationClass   getApplication    isActivityInBackStack HomeActivity class               Activity is in the back stack       else             Activity is not in the back stack

User · Answer

I think the accepted answer is an awful way of handling this   I don t know what the use case is  but please consider a protected method in the base class   protected void doSomething         and override it in the derived class    When the event occurs  just call this method in the base class  The correct  active  class will handle it then  The class itself can then check if it is not Paused     Better yet  use an event bus like GreenRobot s  Square s  but that one is deprecated and suggests using RxJava

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An option without using any auxiliar variable is   activity getWindow   getDecorView   getRootView   isShown     where activity is f e   this or getActivity     The value returned by this expression changes in onStart     onStop    which are the events that start   stop showing the layout of the activity on the phone

User · Answer

ActivityLifecycleCallbacks is a great way of keeping track of all the activities in App   public class BaseActivityLifecycleCallbacks implements Application ActivityLifecycleCallbacks    private ActivityState homeState  contentState    Override public void onActivityCreated Activity activity  Bundle bundle        if  activity instanceof HomeActivityv2            homeState   ActivityState CREATED        else if  activity instanceof ContentDisplayActivity            contentState   ActivityState CREATED            Override public void onActivityStarted Activity activity        if  activity instanceof HomeActivityv2            homeState   ActivityState STARTED        else if  activity instanceof ContentDisplayActivity            contentState   ActivityState STARTED            Override public void onActivityResumed Activity activity        if  activity instanceof HomeActivityv2            homeState   ActivityState RESUMED        else if  activity instanceof ContentDisplayActivity            contentState   ActivityState RESUMED            Override public void onActivityPaused Activity activity        if  activity instanceof HomeActivityv2            homeState   ActivityState PAUSED        else if  activity instanceof ContentDisplayActivity            contentState   ActivityState PAUSED            Override public void onActivityStopped Activity activity        if  activity instanceof HomeActivityv2            homeState   ActivityState STOPPED        else if  activity instanceof ContentDisplayActivity            contentState   ActivityState STOPPED            Override public void onActivitySaveInstanceState Activity activity  Bundle bundle        Override public void onActivityDestroyed Activity activity        if  activity instanceof HomeActivityv2            homeState   ActivityState DESTROYED        else if  activity instanceof ContentDisplayActivity            contentState   ActivityState DESTROYED           public ActivityState getHomeState         return homeState     public ActivityState getContentState         return contentState        ActivityState   public enum ActivityState       CREATED  STARTED  RESUMED  PAUSED  STOPPED  DESTROYED      Extend the Application class and provide its reference in Android Manifest file   import android app Application   public final class BaseApplication extends Application   private BaseActivityLifecycleCallbacks baseALC    Override public void onCreate         super onCreate        baseALC   new BaseActivityLifecycleCallbacks        this registerActivityLifecycleCallbacks baseALC       public BaseActivityLifecycleCallbacks getBaseALC         return baseALC        Ckeck anywhere from Activity for status of other activity   private void checkAndLaunchHomeScreen         Application application   getApplication        if  application instanceof BaseApplication            BaseApplication baseApplication    BaseApplication  application          if  baseApplication getBaseALC   getHomeState      null    baseApplication getBaseALC   getHomeState      ActivityState DESTROYED                  Do anything you want                     https   developer android com reference android app Application ActivityLifecycleCallbacks html

User · Answer

This is code for checking whether a particular service is running  I m fairly sure it can work for an activity too as long as you change getRunningServices with getRunningAppProcesses   or getRunningTasks    Have a look here http   developer android com reference android app ActivityManager html getRunningAppProcesses    Change Constants PACKAGE and Constants BACKGROUND SERVICE CLASS accordingly      public static boolean isServiceRunning Context context         Log i TAG   Checking if service is running         ActivityManager activityManager    ActivityManager context getSystemService Context ACTIVITY SERVICE        List lt RunningServiceInfo gt  services   activityManager getRunningServices Integer MAX VALUE        boolean isServiceFound   false       for  int i   0  i  lt  services size    i               if  Constants PACKAGE equals services get i  service getPackageName                   if  Constants BACKGROUND SERVICE CLASS equals services get i  service getClassName                      isServiceFound   true                                     Log i TAG   Service was     isServiceFound          not       running         return isServiceFound

User · Answer

If you are interested in the lifecycle state of the specific instance of the activity  siliconeagle s solution looks correct except that the new  active  variable should be an instance variable  rather than static

User · Answer

Use an ordered broadcast  See http   android-developers blogspot nl 2011 01 processing-ordered-broadcasts html  In your activity  register a receiver in onStart  unregister in onStop  Now when for example a service needs to handle something that the activity might be able to do better  send an ordered broadcast from the service  with a default handler in the service itself   You can now respond in the activity when it is running  The service can check the result data to see if the broadcast was handled  and if not take appropriate action

User · Answer

I used MyActivity class and getCanonicalName method and I got answer   protected Boolean isActivityRunning Class activityClass            ActivityManager activityManager    ActivityManager  getBaseContext   getSystemService Context ACTIVITY SERVICE           List lt ActivityManager RunningTaskInfo gt  tasks   activityManager getRunningTasks Integer MAX VALUE            for  ActivityManager RunningTaskInfo task   tasks                if  activityClass getCanonicalName   equalsIgnoreCase task baseActivity getClassName                     return true                     return false

User · Answer

Have you tried         if  getActivity   instanceof NameOfYourActivity             Do something

User · Answer

what about activity isFinishing

User · Answer

if  activity isFinishing    amp  amp   activity isDestroyed      From the official docs   Activity isFinishing       Check to see whether this activity is in the process of finishing  either because you called finish   on it or someone else has requested that it finished  This is often used in onPause   to determine whether the activity is simply pausing or completely finishing    Activity isDestroyed       Returns true if the final onDestroy   call has been made on the Activity  so this instance is now dead

User · Answer

You can use a static variable within the activity   class MyActivity extends Activity        static boolean active   false          Override       public void onStart              super onStart             active   true                   Override       public void onStop              super onStop             active   false              The only gotcha is that if you use it in two activities that link to each other then onStop on the first is sometimes called after onStart in second  So both might be true briefly   Depending on what you are trying to do  update the current activity from a service    You could just register a static listener in the service in your activity onStart method then the correct listener will be available when your service wants to update the UI

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This work if you don t have the same activity in foreground  If you open from notification don t work i made some adjustments and came with this   public static boolean ativo   false  public static int counter   0    Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState               counter        Override protected void onStart         super onStart        ativo   true      Override protected void onStop         super onStop        if  counter  1  ativo   false      Override protected void onDestroy         counter--      super onDestroy        That works for me with several activitys open at the same time

User · Answer

In addition to the accepted answer  if you have multiple instances of the activity  you can use a counter instead   class MyActivity extends Activity         static int activeInstances   0        static boolean isActive             return  activeInstance  gt  0                 Override       public void onStart              super onStart             activeInstances                     Override       public void onStop              super onStop             activeInstances--

User · Answer

Found an easy workaround with the following code   Override  protected void onCreate Bundle savedInstanceState                 super onCreate savedInstanceState                if   getIntent   getFlags    amp  Intent FLAG ACTIVITY BROUGHT TO FRONT     0                        Activity is being brought to front and not being  created again                      Thus finishing this activity will bring the last viewed activity to foreground                 finish

User · Answer

I think more clear like that     public boolean isRunning Context ctx            ActivityManager activityManager    ActivityManager  ctx getSystemService Context ACTIVITY SERVICE           List lt RunningTaskInfo gt  tasks   activityManager getRunningTasks Integer MAX VALUE            for  RunningTaskInfo task   tasks                if  ctx getPackageName   equalsIgnoreCase task baseActivity getPackageName                      return true                                                       return false

User · Answer

I used a check if   a isFinishing    and it seems to do what i need  a is the activity instance  Is this incorrect  Why didn t anyone try this

User · Answer

Use the isActivity variable to check if activity is alive or not   private boolean activityState   true     Override protected void onDestroy         super onDestroy        activityState   false      Then check   if activityState     add your code

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I know this question is old and has a lot of varying answers  with various bonuses and drawbacks  My take on it  is why not roll your own IPC implementation  class IPC        companion object           private val appContext   Context by lazy     genericApplicationContext              fun initIPC process  String               var file   File    null             file   File appContext cacheDir absolutePath    quot   process quot               var output   OutputStream    null             try                   output   FileOutputStream file                    output write 0                finally                   output  close                                    fun destroyIPC process  String               var file   File    null             file   File appContext cacheDir absolutePath    quot   process quot               file delete                      fun checkForIPC process  String    Boolean               var file   File    null             file   File appContext cacheDir absolutePath    quot   process quot               if file exists    return true             return false                     This allows you to create the file before launching the activity  and then close out the  quot process file quot  when you close the launched activity  This allows you to check in a background thread or current activity if your  quot process activity quot  is in the background to see if the file is still open signaling that the activity is alive  In my case I am calling an external API in succession but need to rate limit the calls  so use this to make sure only one activity is alive calling the APIs at a time

User · Answer

public static boolean isActivityActive Activity activity        return  activity isFinishing    amp  amp               SDK INT  lt  JELLY BEAN MR1     activity isDestroyed

User · Answer

I have used task topActivity instead of task baseActivity and it works fine for me     protected Boolean isNotificationActivityRunning         ActivityManager activityManager    ActivityManager  getBaseContext   getSystemService Context ACTIVITY SERVICE       List lt ActivityManager RunningTaskInfo gt  tasks   activityManager getRunningTasks Integer MAX VALUE        for  ActivityManager RunningTaskInfo task   tasks            if  task topActivity getClassName   equals NotificationsActivity class getCanonicalName                 return true             return false

User · Answer

Not sure it is a  proper  way to  do things   If there s no API way to resolve the  or a  question than you should think a little  maybe you re doing something wrong and read more docs instead etc   As I understood static variables is a commonly wrong way in android  Of cause it could work  but there definitely will be cases when it wont work for example  in production  on million devices    Exactly in your case I suggest to think why do you need to know if another activity is alive    you can start another activity for result to get its functionality  Or you can derive the class to obtain its functionality and so on  Best Regards

User · Answer

I realize this issue is quite old  but I think it s still worth sharing my solution as it might be useful to others  This solution wasn t available before Android Architecture Components were released  Activity is at least partially visible getLifecycle   getCurrentState   isAtLeast Lifecycle State STARTED   Activity is in the foreground getLifecycle   getCurrentState   isAtLeast Lifecycle State RESUMED

User · Answer

thanks kkudi   I was able to adapt your answer to work for an activity    here s what worked in my app    public boolean isServiceRunning       ActivityManager activityManager    ActivityManager Monitor this getSystemService  Context ACTIVITY SERVICE        List lt RunningTaskInfo gt  services   activityManager getRunningTasks Integer MAX VALUE        isServiceFound   false       for  int i   0  i  lt  services size    i               if  services get i  topActivity toString   equalsIgnoreCase  ComponentInfo com lyo AutoMessage com lyo AutoMessage TextLogList                   isServiceFound   true                       return isServiceFound        this example will give you a true or false if the topActivity matches what the user is doing   So if the activity your checking for is not being displayed  i e  is onPause  then you won t get a match   Also  to do this you need to add the permission to your manifest     lt uses-permission  android name  android permission GET TASKS   gt    I hope this was helpful

[android] Android: how do I check if activity is running?

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