nissanM nissanM - 5 months ago 67
Android Question

Is there an addHeaderView equivalent for RecyclerView?

I'm looking for an equivalent to addHeaderView for a recycler view. Basically I want to have an image with 2 buttons be added as a header to the listview. Is there a different way to add a header view to a recycler view? An example for guidance would be helpful

EDIT 2 (added fragment layouts):

After adding log statements, it seems as though getViewType only ever receives a position of 0. This leads to onCreateView only loading the one layout:

10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemViewType position: 0
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemViewType position: 0
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> getItemViewType position: 0
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> onCreateViewHolder, viewtype: 0
10-26 16:32:53.766 5449-5449/co.testapp I/logger info﹕ Adapter-> onBindViewHolder, viewType: 0


The fragment transition to load the CommentFragment:

@Override
public void onPhotoFeedItemClick(View view, int position) {
if (fragmentManager == null)
fragmentManager = getSupportFragmentManager();

FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

if (view.getId() == R.id.button_comment){
CommentFragment commentFragment = CommentFragment.newInstance("","", position);
fragmentTransaction.add(R.id.main_activity, commentFragment,"comment_fragment_tag");
fragmentTransaction.addToBackStack(Constants.TAG_COMMENTS);
fragmentTransaction.commit();
}
}


The Fragment's onCreateView:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {

View view = inflater.inflate(R.layout.fragment_comment, container, false);
mRecyclerView = (RecyclerView) view.findViewById(R.id.list_recylclerview);
mRecyclerView.setLayoutManager(new LinearLayoutManager(_context));
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
mAdapter = new CommentAdapter(R.layout.row_list_comments, R.layout.row_header_comments, _context, comments);
mRecyclerView.setAdapter(mAdapter);
return view;
}


The fragment containing the recycleview:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
tools:context="co.testapp.fragments.CommentFragment"
android:background="@color/white">
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/list_recylclerview"
android:layout_width="match_parent"
android:layout_height="200dp" />
</RelativeLayout>
</RelativeLayout>


The comments row layout:

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_margin="10dp"
android:background="@color/white">
<!--Profile Picture-->
<ImageView
android:layout_width="80dp"
android:layout_height="80dp"
android:id="@+id/profile_picture"
android:background="@color/blue_testapp"/>
<!--Name-->
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:text="First Name Last Name"
android:textSize="16dp"
android:textColor="@color/blue_testapp"
android:id="@+id/name_of_poster"
android:layout_toRightOf="@id/profile_picture"
/>
<!--Comment-->
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:layout_marginTop="-5dp"
android:text="This is a test comment"
android:textSize="14dp"
android:textColor="@color/black"
android:id="@+id/comment"
android:layout_below="@id/name_of_poster"
android:layout_toRightOf="@id/profile_picture"/>
</RelativeLayout>


The header

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="wrap_content"
android:layout_height="300dp"
android:id="@+id/header_photo"
android:layout_gravity="center_horizontal"/>
</LinearLayout>


The Adapter code (thanks to hister for getting me started):

public class CommentAdapter extends RecyclerView.Adapter<ViewHolder>{

private final int rowCardLayout;
public static Context mContext;
private final int headerLayout;
private final String [] comments;
private static final int HEADER = 0;
private static final int OTHER = 0;

public CommentAdapter(int rowCardLayout, int headerLayout, Context context, String [] comments) {
this.rowCardLayout = rowCardLayout;
this.mContext = context;
this.comments = comments;
this.headerLayout = headerLayout;
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
logger.i("onCreateViewHolder, viewtype: " + i); //viewtype always returns 0 so OTHER layout is never inflated
if (i == HEADER) {
View v = LayoutInflater.from(viewGroup.getContext()).inflate(headerLayout, viewGroup, false);
return new ViewHolderHeader(v);
}
else if (i == OTHER){
View v = LayoutInflater.from(viewGroup.getContext()).inflate(rowCardLayout, viewGroup, false);
return new ViewHolderComments(v);
}
else
throw new RuntimeException("Could not inflate layout");
}

@Override
public void onBindViewHolder(ViewHolder viewHolder, int i) {
logger.i("onBindViewHolder, viewType: " + i);

if (viewHolder instanceof ViewHolderComments)
((ViewHolderComments) viewHolder).comment.setText(comments[i].toString());
if (viewHolder instanceof ViewHolderHeader)
((ViewHolderHeader) viewHolder).header.setImageResource(R.drawable.image2);
else {
logger.e("no instance of viewholder found");
}
}

@Override
public int getItemCount() {
int count = comments.length + 1;
logger.i("getItemCount: " + count);
return count;
}

@Override
public int getItemViewType(int position) {
logger.i("getItemViewType position: " + position);
if (position == HEADER)
return HEADER;
else
return OTHER;
}

public static class ViewHolderComments extends RecyclerView.ViewHolder {
public TextView comment;
public ImageView image;

public ViewHolderComments(View itemView) {
super(itemView);
comment = (TextView) itemView.findViewById(R.id.comment);
image = (ImageView) itemView.findViewById(R.id.image);
}
}

public static class ViewHolderHeader extends RecyclerView.ViewHolder {
public final ImageView header;

public ViewHolderHeader(View itemView){
super(itemView);
header = (ImageView) itemView.findViewById(R.id.header_photo);
}
}
}


Using the above code, only the header layout is displayed as viewType is always 0. It looks like this. If I force the other layout it looks like this:

Answer

There isn't an easy way like listview.addHeaderView() but you can achieve this by adding a type to your adapter for header.

Here is an example

    public class HeaderAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    private static final int TYPE_HEADER = 0;
    private static final int TYPE_ITEM = 1;
    String[] data;

    public HeaderAdapter(String[] data) {
        this.data = data;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if (viewType == TYPE_ITEM) {
            //inflate your layout and pass it to view holder
            return new VHItem(null);
        } else if (viewType == TYPE_HEADER) {
            //inflate your layout and pass it to view holder
            return new VHHeader(null);
        }

        throw new RuntimeException("there is no type that matches the type " + viewType + " + make sure your using types correctly");
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        if (holder instanceof VHItem) {
            String dataItem = getItem(position);
            //cast holder to VHItem and set data
        } else if (holder instanceof VHHeader) {
            //cast holder to VHHeader and set data for header.
        }
    }

    @Override
    public int getItemCount() {
        return data.length + 1;
    }

    @Override
    public int getItemViewType(int position) {
        if (isPositionHeader(position))
            return TYPE_HEADER;

        return TYPE_ITEM;
    }

    private boolean isPositionHeader(int position) {
        return position == 0;
    }

    private String getItem(int position) {
        return data[position - 1];
    }

    class VHItem extends RecyclerView.ViewHolder {
        TextView title;

        public VHItem(View itemView) {
            super(itemView);
        }
    }

    class VHHeader extends RecyclerView.ViewHolder {
        Button button;

        public VHHeader(View itemView) {
            super(itemView);
        }
    }
}

link to gist -> here