CODEWITHSUNDEEP
androidperformanceandroid-recyclerview
AndroidNewbie
AndroidNewbie

Reputation: 5

updating recyclerView in onResume ();

I have encountered some problems in "recreating" an adapter from the recyclerView in the onResume method. Basically, this is my scheme.

MainActivit  -ViewPager
   - fragment A (has a recyclerView)
   - fragment B (nop)
   - fragment C (nop)
   - fragment D (it has the same recyclerView as the framgnet A)

onResume I always call for

> myCustomAdapter adapter = new myCustomAdapter (
> mListItems,getContext(),ParseUser.getCurrentUser().getObjectId(),
> "type");
>                recyclerView.setAdapter(adapter);

but this causes some problems, like when I go back to MainActivity from another activity. For example.

Activityt A
 - click on item in recylerView
 - start Activity B

Activity B
user does some actions, sees some news, and returns to Activity A.

Activity A
recreates the adapter and set recyclerView.setAdapter (new Adapter);
this is slow, causes a delay of 2 seconds after onBackPressed is pressed in Activity B.

I also have a setMenuVisibility method that also does the same thing as onResume, because as informed in fragment D, I have the recyclerView in fragment A, so if a user makes some change in the recyclerView that is in fragment D, I need update the recyclerView of fragment A when the user returns to it.

Why the same recyclerView in Fragment D is in Fragment A?

We can consider the following, in fragment A, I have a recyclerView that contains only the "user interests", and in fragment D, I have user information such as user name, photo, etc ... and also the "user interests".

Conclusion: The problem is when I return from Activity B to Activity A, and when I alternate between fragment A and fragment D in viewPager, this causes a delay for the re-creation of the adapter.

What should I do in this situation?

I apologize for this horrible English, I'm using google translator.

Upvotes: 0

Views: 2044

Answers (2)

sakiM
sakiM

Reputation: 4932

It is a Scope Problem. You need to define adapter in somewhere class member.

  1. If you want the data presented in Fragment A and Fragment D different, then make adapter as a member of each other, and init it in each Fragment.onCreate(). So it won't recreate adapter evert time. (Make sure ViewPager has enough cache number, or it will still recreate the whole non-cached Fragment)

  2. If you want the FragmentA and FragmentD display identical data or part of the same data, create adapter in MainActivity.onCreate and pass it as parameters into FragmentA, FragmentD.

It is not need to recreate adapter every time onResume because it's really a heavy job. No need to change any view layer attributes. Make sure the data(adapter) which you want to share is in the same scope or can pass to it.

For example:

//MainActivity
private Adapter adapter;

void onCreate(Bundle savedInstanceState){
    //...other stuff
    adapter = new myCustomAdapter (mListItems,getContext(),ParseUser.getCurrentUser().getObjectId(), "type");
}
public Adapter getAdapter(){ return adapter;}


//FragmentA or FragmentD
void onCreateView(){
    MainActivity activity = (MainActivity) getActivity(); //This fragment should be created with `MainActivity`
    recyclerView.setAdapter(activity.getAdapter());
}

Upvotes: 3

sziraqui
sziraqui

Reputation: 6112

Do not set set image using "src" attribute of ImageView when dealing with large images or multiple small images Use an image loading library like Glide or Picasso. The following snippet is for Glide v4

Glide.with(context).load(<url_or_res_id>).into(imageView)

You can pass url as string. Or if you are loading images from drawable, you can pass its resource id (eg. R.drawable.image_id)

Upvotes: 0

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