Firebase嵌套子项的Recycleview无法显示

Question

我正在尝试从用户的奖励中填充嵌套子视图，但是我无法在Android App上显示任何内容。关于如何进行的任何建议？请参阅以下有关我到目前为止已编码的代码。

我的模特

public class myrewards{
 String barImg;

public myrewards()
{

}

public myrewards(String barImg) {
    this.barImg = barImg;
}

public String getBarImg() {
    return barImg;
}

public void setBarImg(String barImg) {
    this.barImg = barImg;
}
}

我的观看者

public class RewardViewHolder extends RecyclerView.ViewHolder{


View mView;

public RewardViewHolder(@NonNull View itemView) {
    super(itemView);

    mView = itemView;
}



public void setRewardDetail(Context ctx, String barImg)
{
    ImageView rImg = mView.findViewById(R.id.rImage);

    Picasso.with(ctx).load(barImg).into(rImg);

}

}

我的主要活动

public class MyRewardsActivity extends AppCompatActivity {
private static final String TAG = MyRewardsActivity.class.getSimpleName();
private RecyclerView rRecycleView;
private DatabaseReference myReward, userRef, voucherRef;
private FirebaseAuth mAuth;
private String userID;

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


    ActionBar actionBar = getSupportActionBar();
    actionBar.setTitle("My Rewards");

    rRecycleView = findViewById(R.id.my_reward);
    rRecycleView.setHasFixedSize(true);
    rRecycleView.setLayoutManager(new LinearLayoutManager(this));

    mAuth = FirebaseAuth.getInstance();
    userID = mAuth.getCurrentUser().getUid();

    myReward = FirebaseDatabase.getInstance().getReference().child("User").child(userID);
    userRef = FirebaseDatabase.getInstance().getReference().child("User").child(userID);
    System.out.println("YOUR REWARD= " + myReward);


}

@Override
protected void onStart() {
    super.onStart();
    final FirebaseRecyclerAdapter<myrewards, RewardViewHolder> firebaseRecyclerAdapter =
            new FirebaseRecyclerAdapter<myrewards, RewardViewHolder>
                    (
                         myrewards.class,
                         R.layout.barrewards,
                         RewardViewHolder.class,
                         myReward
                    )
            {
                @Override
                protected void populateViewHolder(RewardViewHolder viewHolder, myrewards model, int position) {

                    viewHolder.setRewardDetail(getApplicationContext() ,model.getBarImg());

                }
            };
    rRecycleView.setAdapter(firebaseRecyclerAdapter);
}
}

下图所示：

我不确定我是否使用了正确的编码方式，就像我一直在使用这种方式从数据库中检索其他数据（不是嵌套子级）一样，是否真的有任何帮助并在此先感谢您。