CODEWITHSUNDEEP
javaandroidandroid-recyclerview
Duy
Duy

Reputation: 67

Android - Why should we use adapter.notifydatasetChanged() method?

I'm implementing a Notepad app using Recyclerview.

When adding, removing and editing note, I will return a newListnote which was modified to display on UI and call adapter.NotifyDataSetChanged().

public static void UpdateUI(List<Entity_NoteItem> newlistNote) {
    /*listNoteToDisplayOnUI = newListNote();
    adapter.notifyDataSetChanged();*/

    adapter = new DisplayUI_CustomIconLabelAdapter(adapter.context, newlistNote);
    myRecyclerView.setAdapter(adapter);
}

But I realized that if I assigned the listNote which is set as data of the adapter by a another object with another memory address, the method NotifyDataSetChanged() will have no effect. Therefore, I decided to new adapter with new listNote and called myRecyclerView.setAdapter(adapter) and it gets more effect.

And my question is: Why should we use the method Adapter.NotifyDataSetChanged() while we can completely new Adapter with the changed data and setAdapter again?

Upvotes: 1

Views: 303

Answers (1)

Ozgur
Ozgur

Reputation: 3756

Why should we use the method Adapter.NotifyDataSetChanged() while we can completely new Adapter with the changed data and setAdapter again???

When you call setAdapter(...), all rows created from scratch. Bu when using notifyDataSetChanged(), old rows can be re-used. So if you want performance, you should use notifyDataSetChanged().

Also RecyclerView.Adapter has these methods too:

notifyItemChanged(int)
notifyItemInserted(int)
notifyItemRemoved(int)
notifyItemRangeChanged(int, int)
notifyItemRangeInserted(int, int)
notifyItemRangeRemoved(int, int)

Upvotes: 4

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