Detect when fragment becomes visible [duplicate]

Answer 1

You could send an event to your activity when the fragment is started : https://www.inkling.com/read/programming-android-mednieks-1st/chapter-11/visualizing-the-fragment-life

By overriding the onStart method :

@Override
public void onStart() {
    super.onStart();
    ((MyInterface)getActivity()).onFragmentIsVisible( this );
}

Where MyInterfaceis an interface :

public MyInterface {
   public void onFragmentVisible( Fragment fragment );
}

and your activity will have to implement it.

This could be more easy with an event bus library like

• RoboGuice's event bus
• Otto
• EventBus

Answer 2

Read about the method : Fragment. isVisible()

Example:

MyFragmentClass test = (MyFragmentClass) getSupportFragmentManager().findFragmentById("myFragnmentID");
if (test != null && test.isVisible()) {
     //VISIBLE! =)
}
else {
    //NOT VISIBLE =(
}

Answer 3

EDIT:
As pointed out in the comments, setUserVisbileHint() does not get called automatically, but by the FragmentPageAdapter when used in a ViewPager.

For the scenario described in the question, onHiddenChanged(boolean hidden) http://developer.android.com/reference/android/app/Fragment.html#onHiddenChanged(boolean) is suitable.
As stated in the documentation, the method gets called every time the Fragments hidden state changes, but not on the initial setup of the Fragment.

---

You could use setUserVisibleHint() http://developer.android.com/reference/android/support/v4/app/Fragment.html#setUserVisibleHint(boolean)

if isVisibleToUseris set to truethe fragment should be displayed.