Methods you override that are part of component creation (onCreate(), onStart(), onResume(), etc.), you should chain to the superclass as the first statement, to ensure that Android has its chance to do its work before you attempt to do something that relies upon that work having been done. Methods you override that are part of … Read more
The following code will help you to post your contents when your app is closed or in the background: import android.app.Service; import android.content.Intent; import android.os.Binder; import android.os.Handler; import android.os.IBinder; import android.widget.Toast; public class SendDataService extends Service { private final LocalBinder mBinder = new LocalBinder(); protected Handler handler; protected Toast mToast; public class LocalBinder extends Binder … Read more
If your view is static, then moving any code to the onActivityCreated method is not necessary. But when you – for instance, fill some lists from the adapter, then you should do it in the onActivityCreated method as well as restoring the view state when setRetainInstance used to do so. Also accessing the view hierarchy … Read more
don’t keep your app in memory You don’t want to block Android from killing your app. What you want is to restore your app’s state properly. Then the user will never notice the app has been destroyed and the user still gets the benefit of an app that was destroyed when not in use. If … Read more
If the process is killed then all static variables will be reinitialized to their default values. So whatever value you have set in Activity A will not persist Good explanation can be viewed here from 2:50 http://www.infoq.com/presentations/Android-Design Here are some instructions for those who want to test this issue manually: Create android v.4 emulator, then … Read more
The FragmentPagerAdapter keeps additional fragments, besides the one shown, in resumed state. The solution is to implement a custom OnPageChangeListener and create a new method for when the fragment is shown. 1) Create LifecycleManager Interface The interface will have two methods and each ViewPager’s Fragment will implement it. These methods Are as follows: public interface … Read more
There is no such call back on a production device for the Application class. The things you want to do should usually be done right after the changes are made, or in the onPause() of the respective app component.
No, if some activity comes into foreground, that doesn’t necessarily mean that the other activity is completely invisible. Consider the following case: Here we see both activities at the same time. The first activity with the fields is obscured by another activity, and the user can no longer interact with it. However, it is still … Read more
This answer uses ProcessLifecycleOwner to detect application visibility. which is a part of Android Architecture Component . 1. add this lib to your project implementation “android.arch.lifecycle:extensions:1.1.1” 2. Extend an application class that implements LifecycleObserver public class AppController extends Application implements LifecycleObserver { /////////////////////////////////////////////// @OnLifecycleEvent(Lifecycle.Event.ON_START) public void onEnterForeground() { Log.d(“AppController”, “Foreground”); isAppInBackground(false); } @OnLifecycleEvent(Lifecycle.Event.ON_STOP) public void … Read more
If you need to synchronize your task with the activity lifecycle, I believe that Loaders are exactly what you need. More specifically, you should use AsyncTaskLoader to do the job. So now instead of running an AsyncTask, you launch your loader, then wait for response in a listener. If the activity is paused, you won’t … Read more