Endless RecyclerView with ProgressBar for pagination

Question

I am using a RecyclerView and fetching objects from an API in batches of ten. For pagination, I use EndlessRecyclerOnScrollListener.

It\'s all working properly. Now

Answer 1

I implemented this on my old project, I did it as follows...

I've created an interface as the guys of your examples did

public interface LoadMoreItems {
  void LoadItems();
}

Then I add added an addOnScrollListener() on my Adapter

 recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView,
                                   int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);

                totalItemCount = linearLayoutManager.getItemCount();
                lastVisibleItem = linearLayoutManager
                        .findLastVisibleItemPosition();
                if (!loading
                        && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
                    //End of the items
                    if (onLoadMoreListener != null) {
                        onLoadMoreListener.LoadItems();
                    }
                    loading = true;

                }
            }
        });

The onCreateViewHolder() is where I put the ProgressBar or not.

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent,
                                                  int viewType) {
    RecyclerView.ViewHolder vh;
    if (viewType == VIEW_ITEM) {
        View v = LayoutInflater.from(parent.getContext()).inflate(
                R.layout.list_row, parent, false);

        vh = new StudentViewHolder(v);
    } else {
        View v = LayoutInflater.from(parent.getContext()).inflate(
                R.layout.progressbar_item, parent, false);

        vh = new ProgressViewHolder(v);
    }
    return vh;
}

On my MainActivity that is where I put the LoadItems() to add the others items is :

mAdapter.setOnLoadMoreListener(new LoadMoreItems() {
        @Override
        public void LoadItems() {
            DataItemsList.add(null);
            mAdapter.notifyItemInserted(DataItemsList.size() - 1);

            handler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    //   remove progress item
                    DataItemsList.remove(DataItemsList.size() - 1);
                    mAdapter.notifyItemRemoved(DataItemsList.size());
                    //add items one by one
                    //When you've added the items call the setLoaded()
                    mAdapter.setLoaded();
                    //if you put all of the items at once call
                    // mAdapter.notifyDataSetChanged();
                }
            }, 2000); //time 2 seconds

        }
    });

For more information I just followed this Github repository(Note: this is using AsyncTask maybe it's useful as my answer, since I did it manually not with data from API but it should work as well) also this post was helpful to me endless-recyclerview-with-progress-bar

Also I don't know if you named it but I also found this post infinite_scrolling_recyclerview, maybe it could also help to you.

If it's not what you are looking for, let me know and tell me what's wrong with this code and I'll try to modify it as your like.

Hope it helps.

EDIT

Since you don't want to remove an item... I found I guess one guy that removes the footer only on this post : diseño-android-endless-recyclerview.

This is for ListView but I know you can adapt it to RecyclerView he's not deleting any item he's just putting Visible/Invisible the ProgressBar take a look : detecting-end-of-listview

Also take a look to : this question android-implementing-progressbar-and-loading-for-endless-list-like-android

Answer 2

Try this simple code :

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recyclerview_cities"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_above="@id/preogressbar"
    />
<ProgressBar
    android:id="@+id/preogressbar"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:visibility="gone"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    />
</RelativeLayout>

Make the progress bar visible when your list items already scrolled and hide when you get data from your service.

Answer 3

I like the idea of adding a progress view holder to an adapter, but it tends to lead to some ugly logic manipulation to get what you want. The view holder approach forces you to guard against the additional footer item by fidgeting with the return values of getItemCount(), getItemViewType(), getItemId(position) and any kind of getItem(position) method that you may want to include.

An alternative approach is to manage the ProgressBar visibility at the Fragment or Activity level by showing or hiding the ProgressBar below the RecyclerView when loading starts and ends respectively. This can be achieved by including the ProgressBar directly in the view layout or by adding it to a custom RecyclerView ViewGroup class. This solution will generally lead to less maintenance and fewer bugs.

UPDATE: My suggestion poses a problem when you scroll the view back up while the content is loading. The ProgressBar will stick to the bottom of the view layout. This is probably not the behavior you want. For this reason, adding a progress view holder to your adapter is probably the best, functional solution. Just don't forget to guard your item accessor methods. :)

Answer 4

here is my workaround without adding a fake item (in Kotlin but simple):

in your adapter add:

private var isLoading = false
private val VIEWTYPE_FORECAST = 1
private val VIEWTYPE_PROGRESS = 2

override fun getItemCount(): Int {
    if (isLoading)
        return items.size + 1
    else
        return items.size
}

override fun getItemViewType(position: Int): Int {
    if (position == items.size - 1 && isLoading)
        return VIEWTYPE_PROGRESS
    else
        return VIEWTYPE_FORECAST
}

override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): RecyclerView.ViewHolder {
    if (viewType == VIEWTYPE_FORECAST)
        return ForecastHolder(LayoutInflater.from(context).inflate(R.layout.item_forecast, parent, false))
    else
        return ProgressHolder(LayoutInflater.from(context).inflate(R.layout.item_progress, parent, false))
}

override fun onBindViewHolder(holder: RecyclerView.ViewHolder?, position: Int) {
    if (holder is ForecastHolder) {
        //init your item
    }
}

public fun showProgress() {
    isLoading = true
}


public fun hideProgress() {
    isLoading = false
}

now you can easily call showProgress() before API call. and hideProgress() after API call was done.

Answer 5

HERE IS SIMPLER AND CLEANER APPROACH.

Implement Endless Scrolling from this Codepath Guide and then follow the following steps.

1. Add progress bar under the RecyclerView.

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rv_movie_grid"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:paddingBottom="50dp"
        android:clipToPadding="false"
        android:background="@android:color/black"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

    </android.support.v7.widget.RecyclerView>

    <ProgressBar
        android:id="@+id/progressBar"
        style="?android:attr/progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="invisible"
        android:background="@android:color/transparent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

Here android:paddingBottom="50dp" and android:clipToPadding="false" are very important.

2. Get a reference to the progress bar.

progressBar = findViewById(R.id.progressBar);

3. Define methods to show and hide progress bar.

void showProgressView() {
    progressBar.setVisibility(View.VISIBLE);
}

void hideProgressView() {
    progressBar.setVisibility(View.INVISIBLE);
}

Answer 6

You can use layout_above tag in recycleView like this:

<RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:layout_marginLeft="16dp"
                    android:layout_marginRight="16dp"
                    android:orientation="vertical">
                    <androidx.recyclerview.widget.RecyclerView
                        android:id="@+id/rv"
                        android:layout_below="@+id/tv2"
                        android:layout_width="match_parent"
                        android:focusable="false"
                        android:layout_height="wrap_content"
                        android:layout_marginTop="24dp"
                        android:layout_above="@+id/pb_pagination"/>

                     <ProgressBar
                        android:id="@+id/pb_pagination"
                        style="@style/Widget.AppCompat.ProgressBar"
                        android:layout_width="30dp"
                        android:layout_height="30dp"
                        android:indeterminate="true"
                         android:visibility="gone"
                        android:layout_alignParentBottom="true"
                        android:layout_centerHorizontal="true" />
    </RelativeLayout>