Is it okay to use/invoke new Handler() in a loop?

Question

I am using new Handler().postDelayed to set a delay when reloading an ad when the previous request of the ad has failed in the requestNewInterstitial method. I am wondering if invoking/creating many new Handlers would be okay as in my loop the new Handler line of code could be run up to 5 times. My question is, if later I have to clear the handler in the Activity onDestroy method so that there are no memory leaks, should I clear it only once or should I clean all the new Handlers I have created (the number of times that the loop is run). Also, how could I implement to clear the Handler OnDestroy method?

This is my code:

 @Override
      protected void onResume() {
        super.onResume();
        requestNewInterstitial(5);

        }


 private void requestNewInterstitial(int maxRetry) {
        AdRequest adRequest = new AdRequest.Builder().build();
        InterstitialAd.load(Activityone.this, getString(R.string.interid),
                adRequest, new InterstitialAdLoadCallback() {
                    @Override
                    public void onAdLoaded(@NonNull InterstitialAd interstitialAd) {
                        mInterstitialAd = interstitialAd;
                    }

                    @Override
                    public void onAdFailedToLoad(@NonNull LoadAdError loadAdError) {


          if (maxRetry>0){
                         
                    new Handler().postDelayed(new Runnable() {
          @Override
          public void run() {
              mInterstitialAd = null;
              requestNewInterstitial(maxRetry-1);

          }
      }, 1000);
              
                   
                    }
                });
                     }
           
    }




  btnPause.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
            
                if (mInterstitialAd != null) {

                    mInterstitialAd.show(Activityone.this);

                    mInterstitialAd.setFullScreenContentCallback(new FullScreenContentCallback() {
                        @Override
                        public void onAdDismissedFullScreenContent() {
                  
                        }

                        @Override
                        public void onAdFailedToShowFullScreenContent(@NonNull AdError adError) {

                        }

                    });

Thanks for the help.

Answer 1

If the delay in postDelay extends beyound the activity lifetime, the runnable will execute after the activity has been destryed and will lead app crash. You should use a common handler. To clear the handler, you can call handler.removeCallbacksAndMessages(null); in on destroy or wherever else you want to clear them.

Handler handler;

@Override
public void onCreate(@Nullable Bundle savedInstanceState, @Nullable PersistableBundle persistentState) {
    super.onCreate(savedInstanceState, persistentState);

    handler = new Handler();
    btnPause.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            if (mInterstitialAd != null) {

                mInterstitialAd.show(Activityone.this);

                mInterstitialAd.setFullScreenContentCallback(new FullScreenContentCallback() {
                    @Override
                    public void onAdDismissedFullScreenContent() {

                    }

                    @Override
                    public void onAdFailedToShowFullScreenContent(@NonNull AdError adError) {

                    }

                });
            }
        }
    });
}

@Override
protected void onResume() {
    super.onResume();
    requestNewInterstitial(5);

}

@Override
protected void onDestroy() {
    handler.removeCallbacksAndMessages(null)
    super.onDestroy();
}


private void requestNewInterstitial(int maxRetry) {
    AdRequest adRequest = new AdRequest.Builder().build();
    InterstitialAd.load(Activityone.this, getString(R.string.interid), adRequest, new InterstitialAdLoadCallback() {
        @Override
        public void onAdLoaded(@NonNull InterstitialAd interstitialAd) {
            mInterstitialAd = interstitialAd;
        }

        @Override
        public void onAdFailedToLoad(@NonNull LoadAdError loadAdError) {


            if (maxRetry > 0) {

                handler.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        mInterstitialAd = null;
                        requestNewInterstitial(maxRetry - 1);

                    }
                }, 1000);


            }
        }
    });
}