adapter.setHasStableIds(true) 为什么在 RecyclerView 中默认不启用？

Question

I can see setting adapter.

setHasStableIds(true);

will improved RecyclerView performance, since it is improving lots of performance, why it is not default enabled in RecyclerView , Is there any limitations while setting setHasStableIds(true) ?

Answer 1

The reason is when we are going to just displaying the data in recycler-view that case no need to unique id of each item and no animation required. so it's default its false .

But when we are going to perform some action in the dataset and update the recycler-view that case its need unique id for particular item and refreshing animation (blinking) it need.so we set as true

Answer 2

The reason why it is not the default is because the data backing the adapter might not have stable Id's and the RecyclerView does not know this.

Yes there is a limitation one using setHasStableIds(true) - your data has to have stable Id's

You either need override getItemId(int position) to return a unique Id that would represent each Data Item, simply return the HashCode if you cannot think of anything better.

Or

If using something like a CursorAdapter this automatic has stable Id's as it uses the database table _id column.