How to call a method after a delay in Android

Question

I want to be able to call the following method after a specified delay   In objective c there was something like    self performSelector  selector DoSomething  withObject nil afterDelay 5     Is there an equivalent of this method in android with java  For example I need to be able to call a method after 5 seconds   public void DoSomething            do something here

User · Answer

Thanks for all the great answers  I found a solution that best suits my needs   Handler myHandler   new DoSomething    Message m   new Message    m obj   c   passing a parameter here myHandler sendMessageDelayed m  1000    class DoSomething extends Handler        Override     public void handleMessage Message msg          MyObject o    MyObject  msg obj          do something here

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More Safety - With Kotlin Most of the answers use Handler but I give a different solution to delay in activity  fragment  view model with Android Lifecycle ext  This way will auto cancel when the lifecycle begins destroyed  In Activity or Fragment  lifecycleScope launch      delay DELAY MS    doSomething      In ViewModel  viewModelScope lanch     delay DELAY MS    doSomething      In suspend function   Kotlin Coroutine  suspend fun doSomethingAfter        delay DELAY MS      doSomething      If you get an error with the lifecycleScope not found - import to gradle file  implementation  quot androidx lifecycle lifecycle-runtime-ktx 2 2 0 quot

User · Answer

you can use Handler inside UIThread   runOnUiThread new Runnable           Override     public void run              final Handler handler   new Handler             handler postDelayed new Runnable                 Override            public void run                      add your code here                          1000

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Here is another tricky way  it won t throw exception when the runnable change UI elements   public class SimpleDelayAnimation extends Animation implements Animation AnimationListener        Runnable callBack       public SimpleDelayAnimation Runnable runnable  int delayTimeMilli            setDuration delayTimeMilli           callBack   runnable          setAnimationListener this               Override     public void onAnimationStart Animation animation                 Override     public void onAnimationEnd Animation animation            callBack run                Override     public void onAnimationRepeat Animation animation               You can call the animation like this   view startAnimation new SimpleDelayAnimation delayRunnable  500      Animation can attach to any view

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There are a lot of ways to do this but the best is to use handler like below  long millisecDelay 3000  Handler   postDelayed        do your work here    millisecDelay

User · Answer

So there are a few things to consider here as there are so many ways to skin this cat  Although answers have all already been given selected and chosen  I think it s important that this gets revisited with proper coding guidelines to avoid anyone going the wrong direction just because of  majority selected simple answer    So first let s discuss the simple Post Delayed answer that is the winner selected answer overall in this thread   A couple of things to consider  After the post delay  you can encounter memory leaks  dead objects  life cycles that have gone away  and more  So handling it properly is important as well  You can do this in a couple of ways   For sake of modern development  I ll supply in KOTLIN  Here is a simple example of using the UI thread on a callback and confirming that your activity is still alive and well when you hit your callback     Handler Looper getMainLooper    postDelayed               if activity    null  amp  amp  activity  isFinishing    false                   txtNewInfo visibility   View GONE                          NEW INFO SHOW TIMEOUT MS    However  this is still not perfect as there is no reason to hit your callback if the activity has gone away  so a better way would be to keep a reference to it and remove it s callbacks like this       private fun showFacebookStylePlus1NewsFeedOnPushReceived            A35Log v TAG   showFacebookStylePlus1NewsFeedOnPushReceived           if activity    null  amp  amp  activity  isFinishing    false               txtNewInfo visibility   View VISIBLE             mHandler postDelayed                   if activity    null  amp  amp  activity  isFinishing    false                       txtNewInfo visibility   View GONE                                  NEW INFO SHOW TIMEOUT MS                    and of course handle cleanup on the onPause so it doesn t hit the callback       override fun onPause             super onPause           mHandler removeCallbacks null          Now that we have talked through the obvious  let s talk about a cleaner option with modern day coroutines and kotlin     If you aren t using these yet  you are really missing out      fun doActionAfterDelay            launch UI                delay MS TO DELAY                         actionToTake                     or if you want to always do a UI launch on that method you can simply do     fun doActionAfterDelay     launch UI          delay MS TO DELAY                   actionToTake         Of course just like the PostDelayed you have to make sure you handle canceling so you can either do the activity checks after the delay call or you can cancel it in the onPause just like the other route   var mDelayedJob  Job    null fun doActionAfterDelay       mDelayedJob   launch UI                try                  delay MS TO DELAY                            actionToTake                catch ex  JobCancellationException                   showFancyToast  Delayed Job canceled   true  FancyToast ERROR   Delayed Job canceled    ex message                                       handle cleanup  override fun onPause        super onPause      if mDelayedJob    null  amp  amp  mDelayedJob   isActive          A35Log v mClassTag   canceling delayed job         mDelayedJob  cancel     this should throw CancelationException in coroutine  you can catch and handle appropriately          If you put the launch UI  into the method signature the job can be assigned in the calling line of code   so moral of the story is to be safe with your delayed actions  make sure you remove your callbacks  or cancel your jobs and of course confirm you have the right life cycle to touch items on your delay callback complete  The Coroutines also offers cancelable actions   Also worth noting that you should typically handle the various exceptions that can come with coroutines  For example  a cancelation  an exception  a timeout  whatever you decide to use  Here is a more advanced example if you decide to really start utilizing coroutines      mLoadJob   launch UI               try                     Applies timeout                 withTimeout 4000                          Moves to background thread                     withContext DefaultDispatcher                            mDeviceModelList addArrayList SSDBHelper getAllDevices                                                               Continues after async with context above                 showFancyToast  Loading complete   true  FancyToast SUCCESS               catch ex  JobCancellationException                   showFancyToast  Save canceled   true  FancyToast ERROR   Save canceled    ex message                 catch  ex  TimeoutCancellationException                    showFancyToast  Timed out saving  please try again or press back   true  FancyToast ERROR   Timed out saving to database    ex message                 catch ex  Exception                   showFancyToast  Error saving to database  please try again or press back   true  FancyToast ERROR   Error saving to database    ex message

User · Answer

If you are using Android Studio 3 0 and above you can use lambda expressions  The method callMyMethod   is called after 2 seconds   new Handler   postDelayed    - gt  callMyMethod    2000     In case you need to cancel the delayed runnable use this   Handler handler   new Handler    handler postDelayed    - gt  callMyMethod    2000       When you need to cancel all your posted runnables just use  handler removeCallbacksAndMessages null

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For executing something in the UI Thread after 5 seconds   new Handler Looper getMainLooper    postDelayed new Runnable          Override     public void run               Do something here          5000

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It s very easy using the CountDownTimer  For more details https   developer android com reference android os CountDownTimer html  import android os CountDownTimer      calls onTick every second  finishes after 3 seconds new CountDownTimer 3000  1000         public void onTick long millisUntilFinished          Log d  log   millisUntilFinished   1000            public void onFinish              called after count down is finished         start

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everybody seems to forget to clean the Handler before posting a new runnable or message on it  Otherway they could potentially accumulate and cause bad behaviour   handler removeMessages int what      Remove any pending posts of messages with code  what  that are in the message queue   handler removeCallbacks Runnable r     Remove any pending posts of Runnable r that are in the message queue

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final Handler handler   new Handler     Timer t   new Timer     t schedule new TimerTask          public void run              handler post new Runnable                  public void run                        DO SOME ACTIONS HERE   THIS ACTIONS WILL WILL EXECUTE AFTER 5 SECONDS                                         5000

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Below one works when you get      java lang RuntimeException  Can t create handler inside thread that   has not called Looper prepare     final Handler handler   new Handler Looper getMainLooper     handler postDelayed new Runnable        Override   public void run           Do something after 100ms        100

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I created simpler method to call this    public static void CallWithDelay long miliseconds  final Activity activity  final String methodName                new Handler   postDelayed new Runnable                   Override             public void run                     try                       Method method    activity getClass   getMethod methodName                       method invoke activity                     catch  NoSuchMethodException e                        e printStackTrace                      catch  InvocationTargetException e                        e printStackTrace                      catch  IllegalAccessException e                        e printStackTrace                                               miliseconds           To use it  just call    CallWithDelay 5000  this   DoSomething

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A suitable solution in android    private static long SLEEP TIME   2    for 2 second     MyLauncher launcher   new MyLauncher                launcher start        private class MyLauncher extends Thread            Override                        Sleep for 2 seconds as you can also change SLEEP TIME 2 to any                       public void run                 try                      Sleeping                 Thread sleep SLEEP TIME   1000                 catch  Exception e                    Log e TAG  e getMessage                                 do something you want to do              And your code will be executed after 2 second

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Using Kotlin  we can achieve by doing the following  Handler   postDelayed          do something after 1000ms     1000

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Here is my shortest solution    new Handler   postDelayed new Runnable          Override     public void run               Do something after 100ms          100

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See this demo   import java util Timer  import java util TimerTask   class Test        public static void main  String    args               int delay   5000    in ms             Timer timer   new Timer               timer schedule  new TimerTask                 public void run                       System out println  Wait  what                                     delay               System out println  Would it run

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In Android  we can write below kotlin code for delay execution of any function    class MainActivity   AppCompatActivity      private lateinit var handler  Handler  override fun onCreate savedInstanceState  Bundle         super onCreate savedInstanceState      setContentView R layout activity main      handler  Handler       handler postDelayed           doSomething         2000     private fun doSomething         Toast makeText this  Hi  I am Toast Message  Toast LENGTH SHORT  show

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If you have to use the Handler  but you are into another thread  you can use runonuithread to run the handler in UI thread  This will save you from Exceptions thrown asking to call Looper Prepare    runOnUiThread new Runnable          Override     public void run             new Handler   postDelayed new Runnable                  Override             public void run                       Do something after 1 second                          1000               Looks quite messy  but this is one of the way

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I like things cleaner  Here is my implementation  inline code to use inside your method   new Handler   postDelayed new Runnable        Override   public void run           Do something after 100ms        100

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I suggest the Timer  it allows you to schedule a method to be called on a very specific interval  This will not block your UI  and keep your app resonsive while the method is being executed   The other option  is the wait    method  this will block the current thread for the specified length of time  This will cause your UI to stop responding if you do this on the UI thread

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You can use this for Simplest Solution   new Handler   postDelayed new Runnable          Override     public void run               Write your code here          5000     Timer is in ms here    Else  Below can be another clean useful solution   new Handler   postDelayed    - gt      Do something here      5000     time in ms

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I couldn t use any of the other answers in my case  I used the native java Timer instead   new Timer   schedule new TimerTask                    Override     public void run                this code will be executed after 2 seconds                 2000

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Kotlin     Handler Looper getMainLooper    postDelayed           Do something after 100ms        100    Java     final Handler handler   new Handler Looper getMainLooper         handler postDelayed new Runnable            Override       public void run               Do something after 100ms                100

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Note  This answer was given when the question didn t specify Android as the context  For an answer specific to the Android UI thread look here     It looks like the Mac OS API lets the current thread continue  and schedules the task to run asynchronously  In the Java  the equivalent function is provided by the java util concurrent package  I m not sure what limitations Android might impose   private static final ScheduledExecutorService worker      Executors newSingleThreadScheduledExecutor     void someMethod           Runnable task   new Runnable         public void run              Do something                    worker schedule task  5  TimeUnit SECONDS

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Kotlin  amp  Java Many Ways   1  Using Handler  Handler   postDelayed       TODO  Do something          2000    2  Using TimerTask  Timer   schedule object   TimerTask         override fun run             TODO  Do something            2000    Or even shorter  Timer   schedule timerTask       TODO  Do something      2000    Or shortest would be  Timer   schedule 2000        TODO  Do something       3  Using Executors  Executors newSingleThreadScheduledExecutor   schedule       TODO  Do something      2  TimeUnit SECONDS       In Java   1  Using Handler  new Handler   postDelayed new Runnable          Override     public void run               Do something          2000     2  Using Timer  new Timer   schedule new TimerTask                    Override     public void run                Do something          2000     3  Using ScheduledExecutorService  private static final ScheduledExecutorService worker   Executors newSingleThreadScheduledExecutor     Runnable runnable   new Runnable       public void run              Do something          worker schedule runnable  2  TimeUnit SECONDS

User · Answer

I prefer to use View postDelayed   method  simple code below   mView postDelayed new Runnable          Override     public void run                Do something after 1000 ms          1000

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For a Simple line Handle Post delay  you can do as following    new Handler   postDelayed new Runnable          Override     public void run                Do someting          3000     I hope this helps

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If you use RxAndroid then thread and error handling becomes much easier  Following code executes after a delay     Observable timer delay  TimeUnit SECONDS           subscribeOn Schedulers io             observeOn AndroidSchedulers mainThread             subscribe aLong - gt                  Execute code here            Throwable  printStackTrace

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Similar solution but much cleaner to use   Write this function out side of class  fun delay duration  Long   do      - gt  Unit         Handler   postDelayed  do   duration       Usage   delay 5000          Do your work here

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Here is the answer in Kotlin you lazy  lazy people   Handler   postDelayed     doSomethingHere      1000

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You can make it much cleaner by using the newly introduced lambda expressions   new Handler   postDelayed    - gt     your code here     time

[java] How to call a method after a delay in Android

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