单击另一个片段的Backpressed后返回时恢复片段状态

Question

Here is my problem area:

I have a Fragment A. Once it is attached, in its onCreateView, I load a webservice to fetch the data from the server and after that I set that data on the list view using a Base Adapter. Now on the Item Clicks of the list view I replace the Fragment A with Fragment B using replace Methods of the Fragment Transactions and addtoBackstack("FragmentA").

FragmentManager fm =getActivity().getFragmentManager();
fm.beginTransaction().replace(R.id.content_frame, Fragment B).commit();

Now here when I press back button on Fragment B, it takes me to Fragment A but the webservice again starts loading.

My Problem: I just want that when it returns to Fragment A, it should show its previous state and should not call the webservices again.

Thanks

Answer 1

OnCreateView for a fragment runs on the creation of the view every time it needs to be drawn. By going back you are causing the view to be recreated and hence the webservices are loading again.

I believe that if you only want the web services to load once then you could move the code to the "onCreate" method instead, but its probably a better idea to move this code to "onResume" instead and include some logic that checks whether you need to load your webservices again or not.

This way everytime the fragment is paused and then loaded again you could ensure that the fragment still has everything it needs.

_{(source: xamarin.com )}

EDIT:

So for example you could have

 @Override
 public void onResume() {
 super.onResume();  // Always call the superclass method first


 if (data == null) { //Or list is empty?
    getWebData()
 }
}