Remove all items from RecyclerView

问题

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

回答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();
}

回答2:

Avoid deleting your items in a for loop and calling notifyDataSetChanged in every iteration. Instead just call the clear method in your list myList.clear(); and then notify your adapter

public void clearData() {
    myList.clear(); // clear list
    mAdapter.notifyDataSetChanged(); // let your adapter know about the changes and reload view.
}

回答3:

setAdapter(null);

Useful if RecycleView have different views type

回答4:

recyclerView.removeAllViewsInLayout();

The above line would help you remove all views from the layout.

For you:

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

    recyclerView.removeAllViewsInLayout(); //removes all the views

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

回答5:

This is how I cleared my recyclerview and added new items to it with animation:

mList.clear();
mAdapter.notifyDataSetChanged();

mSwipeRefreshLayout.setRefreshing(false);

//reset adapter with empty array list (it did the trick animation)
mAdapter = new MyAdapter(context, mList);
recyclerView.setAdapter(mAdapter);

mList.addAll(newList);
mAdapter.notifyDataSetChanged();

回答6:

Help yourself:

public void clearAdapter() {
    arrayNull.clear();
    notifyDataSetChanged();
}

回答7:

Another way to clear the recycleview items is to instanciate a new empty adapter.

mRecyclerView.setAdapter(new MyAdapter(this, new ArrayList<MyDataSet>()));

It's probably not the most optimized solution but it's working like a charm.

回答8:

ListView uses clear().

But, if you're just doing it for RecyclerView. First you have to clear your RecyclerView.Adapter with notifyItemRangeRemoved(0,size)

Then, only you recyclerView.removeAllViewsInLayout().

回答9:

For my case adding an empty list did the job.

List<Object> data = new ArrayList<>();
adapter.setData(data);
adapter.notifyDataSetChanged();

回答10:

private void clearRecyclerView() {
    CustomListViewValuesArr.clear();
    customRecyclerViewAdapter.notifyDataSetChanged();
}

use this func

回答11:

On Xamarin.Android, It works for me and need change layout

 var layout = recyclerView.GetLayoutManager() as GridLayoutManager;
 layout.SpanCount = GetItemPerRow(Context);
 recyclerView.SetAdapter(null);
 recyclerView.SetAdapter(adapter); //reset

回答12:

public void clearData() {
    mylist.removeAll(mylist);
    mAdapter.notifyDataSetChanged();
    recyclerView.setAdapter(mAdapter);
}

来源：https://stackoverflow.com/questions/29978695/remove-all-items-from-recyclerview