Firebase RecyclerAdapter not working

Question

I'm trying to display my data from Firebase database into a RecyclerView using Firebase RecyclerAdapter. I am quite new to this and not being able to figure what problem I am facing.

    import android.content.Context;
    import android.support.annotation.NonNull;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.support.v7.widget.LinearLayoutManager;
    import android.support.v7.widget.RecyclerView;
    import android.support.v7.widget.Toolbar;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.TextView;


    import com.firebase.ui.database.FirebaseRecyclerAdapter;
    import com.firebase.ui.database.FirebaseRecyclerOptions;
    import com.google.firebase.database.DatabaseReference;
    import com.google.firebase.database.FirebaseDatabase;

    import com.squareup.picasso.Picasso;

    import org.w3c.dom.Text;

    import de.hdodenhof.circleimageview.CircleImageView;

public class AllUsersActivity extends AppCompatActivity {

private Toolbar mToolbar;
private RecyclerView allUsersList;
private DatabaseReference allDatabaseUserreference;




@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_all_users);

    mToolbar = (Toolbar)findViewById(R.id.all_users_app_bar);
    setSupportActionBar(mToolbar);
    getSupportActionBar().setTitle("All Users");
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    allUsersList = (RecyclerView)findViewById(R.id.all_users_list);
    allUsersList.setHasFixedSize(true);
    allUsersList.setLayoutManager(new LinearLayoutManager(this));
    allDatabaseUserreference = FirebaseDatabase.getInstance().getReference().child("Users");

}



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

    FirebaseRecyclerOptions<AllUsers> options =
            new FirebaseRecyclerOptions.Builder<AllUsers>()
                    .setQuery(allDatabaseUserreference, AllUsers.class)
                    .build();

    FirebaseRecyclerAdapter adapter = new FirebaseRecyclerAdapter<AllUsers, AllUsersViewHolder>(options) {
        @Override
        public AllUsersViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.all_users_display_layout, parent, false);

            return new AllUsersViewHolder(view);
        }

        @Override
        protected void onBindViewHolder(AllUsersViewHolder viewHolder, int position, AllUsers model) {

            viewHolder.setUser_name(model.getUser_name());
            viewHolder.setUser_status(model.getUser_status());
            viewHolder.setUser_image(getApplicationContext(),model.getUser_image());

        }
    };

    allUsersList.setAdapter(adapter);


}

public static class AllUsersViewHolder extends RecyclerView.ViewHolder{

    View mView;

    public AllUsersViewHolder(View itemView) {

        super(itemView);
        mView = itemView;
    }

    public void setUser_name(String user_name){

        TextView name = (TextView)mView.findViewById(R.id.all_users_username);
        name.setText(user_name);

    }

    public void setUser_status(String user_status){

        TextView status = (TextView)mView.findViewById(R.id.all_users_status);
        status.setText(user_status);
    }

    public void setUser_image(Context ctx, String user_image){

        CircleImageView image = (CircleImageView) mView.findViewById(R.id.all_users_profile_image);
        Picasso.get().load(user_image).into(image);
    }
}

}

This is my layout file

    <?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="com.example.swapnil.chitchat.AllUsersActivity">

    <include
        layout="@layout/app_bar_layout"
        android:id="@+id/all_users_app_bar">

    </include>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/all_users_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentBottom="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/all_users_app_bar">

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

This type of layout should be generated on Recycler view.

     <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_margin="15dp">

        <de.hdodenhof.circleimageview.CircleImageView
            android:id="@+id/all_users_profile_image"
            android:layout_width="85dp"
            android:layout_height="85dp"
            android:src="@drawable/defualt_image_profile"/>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:layout_margin="5dp">

                <TextView
                    android:id="@+id/all_users_username"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="User Name"
                    android:textSize="18sp"
                    android:textStyle="bold"/>

            <TextView
                android:id="@+id/all_users_status"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="5dp"
                android:text="User Status"
                android:textSize="15sp"
                android:textStyle="bold" />

        </LinearLayout>
    </LinearLayout>



</LinearLayout>

This is my class for RecyclerAdapter

public class AllUsers {

    public String user_name;
    public String user_status;
    public String user_image;

    public AllUsers(){

    }

    public AllUsers(String user_name, String user_status, String user_image) {
        this.user_name = user_name;
        this.user_status = user_status;
        this.user_image = user_image;
    }

    public String getUser_name() {
        return user_name;
    }

    public void setUser_name(String user_name) {
        this.user_name = user_name;
    }

    public String getUser_status() {
        return user_status;
    }

    public void setUser_status(String user_status) {
        this.user_status = user_status;
    }

    public String getUser_image() {
        return user_image;
    }

    public void setUser_image(String user_image) {
        this.user_image = user_image;
    }
}

When I run the app , all I am getting is a blank screen.There are no errors while I compile or run the code.I tried debugging the code by writing a Toast message in onCreateViewHolder method but it is not getting executed.