populateViewHolder() isn't getting executed in a FirebaseRecyclerAdapter for the first time when app runs

FirebaseRecyclerAdapter - populateViewHolder is not populating the data for the first time it runs but when I closed the app and opened it, the data is binded in RecyclerView View Holder. I am not getting why data is not populating for first time, it is showing blank screen

One more observation if I am debugging the app and wait at the debug point on Query for 2-3 seconds populateViewHolder is called and the view displays … No idea why this is happening

Main Activity

mDatabase = FirebaseDatabase.getInstance().getReference();
        // [END create_database_reference]

        mRecycler = (RecyclerView) findViewById(R.id.recycler_view);
        mRecycler.setHasFixedSize(true);
        setSupportActionBar(toolbar);
        final LinearLayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        layoutManager.setReverseLayout(true);
        layoutManager.setStackFromEnd(true);
        mRecycler.setLayoutManager(layoutManager);




        // Set up FirebaseRecyclerAdapter with the Query
        //Query postsQuery = mDatabase.child("EN").child("Courses") ;
        DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("EN").child("Courses");
        ref.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                Toast.makeText(MainActivity.this, dataSnapshot.toString(), Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                Toast.makeText(MainActivity.this, databaseError.toString(), Toast.LENGTH_SHORT).show();
            }
        });
        Log.d("ref", String.valueOf(ref));
        //   Log.d("Query", String.valueOf(postsQuery));
        mAdapter = new FirebaseRecyclerAdapter<Course, CourseViewHolder>(Course.class, R.layout.item_home,
                CourseViewHolder.class, ref) {
            @Override
            protected void populateViewHolder(final CourseViewHolder viewHolder, final Course model, final int position) {
                viewHolder.bindToPost(model);
            }

        };
        mRecycler.setAdapter(mAdapter);`

ViewHolder

`public class CourseViewHolder extends RecyclerView.ViewHolder {

public TextView titleView;
public TextView descriptionView;
public ImageView IconView;
public TextView lessonCountView;


public CourseViewHolder(View itemView) {
    super(itemView);

    titleView = (TextView) itemView.findViewById(R.id.title);
    descriptionView = (TextView) itemView.findViewById(R.id.description);
    //IconView = (ImageView) itemView.findViewById(R.id.star);

}

public void bindToPost(Course post) {
  //  Log.d("Post", String.valueOf(post));
    titleView.setText(post.getName());
    descriptionView.setText(post.getDescription());

}
}`

My Model Pojo

@IgnoreExtraProperties
   public class Course {

public String description;
public String title;


public Course() {
    // Default constructor required for calls to DataSnapshot.getValue(Post.class)
}

public Course(String title, String description) {
  //  this.description = author;
    this.title = title;
    this.description =description;

}

public String getName() {
    return title;
}


public String getDescription() {
    return description;
}



 }

[prashanth726]

The Problem is RecyclerView had a height of WrapContent , So Please Make Sure your recycler Height is set to Match_Parent. This will fix this issue.

  <android.support.v7.widget.RecyclerView
            android:id="@+id/recycler_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:scrollbars="vertical"
            />

[filipebezerra]

The same bug happened with me. I have the same view logic as @itsPR. Was solved using his solution, applying android:layout_height=“match_parent” to my RecyclerView.

So, in my oppinion this is a bug.