android - Remove all items from RecyclerView

Question

I am trying to remove all the elements from my RecyclerView in my onRestart method so the items don't get loaded twice:

@Override
protected void onRestart() {
    super.onRestart();

    // first clear the recycler view so items are not populated twice
    for (int i = 0; i < recyclerAdapter.getSize(); i++) {
        recyclerAdapter.delete(i);
    }

    // then reload the data
    PostCall doPostCall = new PostCall(); // my AsyncTask... 
    doPostCall.execute();
}

But for some reason the delete method I created in the adapter is not functioning properly:

in RecyclerAdapter.java:

public void delete(int position){
    myList.remove(position);
    notifyItemRemoved(position);
}

public int getSize(){
    return myList.size();
}

I think every other item in my list gets deleted instead of the entire list.

With a listview it was so easy and I simply called adapter.clear().

Can someone please help me fix up the code?

I think I should be using notifyItemRangeRemoved(...,...); but I am not sure how. TIA

Answer 1

This works great for me:

public void clear() {
    int size = data.size();
    if (size > 0) {
        for (int i = 0; i < size; i++) {
            data.remove(0);
        }

        notifyItemRangeRemoved(0, size);
    }
}

Source: https://github.com/mikepenz/LollipopShowcase/blob/master/app/src/main/java/com/mikepenz/lollipopshowcase/adapter/ApplicationAdapter.java

or:

public void clear() {
    int size = data.size();
    data.clear();
    notifyItemRangeRemoved(0, size);
}

For you:

@Override
protected void onRestart() {
    super.onRestart();

    // first clear the recycler view so items are not populated twice
    recyclerAdapter.clear();

    // then reload the data
    PostCall doPostCall = new PostCall(); // my AsyncTask... 
    doPostCall.execute();
}