Приложение продолжает сбой с "E / RecyclerView: адаптер не подключен; пропускает макет"

Question

Мое приложение продолжает падать всякий раз, когда я пытаюсь открыть макет с RecyclerView.

По-видимому, я получаю эту ошибку:

E/RecyclerView: No adapter attached; skipping layout

Код был в основном скопирован из документации .

MyAdapter.java

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
    private String[] mDataset;

    // Provide a reference to the views for each data item
    // Complex data items may need more than one view per item, and
    // you provide access to all the views for a data item in a view holder
    public static class MyViewHolder extends RecyclerView.ViewHolder {
        // each data item is just a string in this case
        public TextView textView;
        public MyViewHolder(TextView v) {
            super(v);
            textView = v;
        }
    }

    // Provide a suitable constructor (depends on the kind of dataset)
    public MyAdapter(String[] myDataset) {
        mDataset = myDataset;
    }

    // Create new views (invoked by the layout manager)
    @Override
    public MyAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent,
                                                     int viewType) {
        // create a new view
        TextView v = (TextView) LayoutInflater.from(parent.getContext())
                .inflate(R.layout.my_text_view, parent, false);
        MyViewHolder vh = new MyViewHolder(v);
        return vh;
    }

    // Replace the contents of a view (invoked by the layout manager)
    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        // - get element from your dataset at this position
        // - replace the contents of the view with that element
        holder.textView.setText(mDataset[position]);

    }

    // Return the size of your dataset (invoked by the layout manager)
    @Override
    public int getItemCount() {
        return mDataset.length;
    }
}

ChatActivity.java

public class ChatActivity extends AppCompatActivity{
    private RecyclerView recyclerView;
    private RecyclerView.Adapter mAdapter;
    private RecyclerView.LayoutManager layoutManager;
    String[] myDataset = {"Hello", "Who r u", "Wait what", "Nice to meet you", "Yeet"};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_chat);
        recyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);

        // use this setting to improve performance if you know that changes
        // in content do not change the layout size of the RecyclerView
        recyclerView.setHasFixedSize(true);

        // use a linear layout manager
        layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);

        // specify an adapter (see also next example)
        mAdapter = new MyAdapter(myDataset);
        recyclerView.setAdapter(mAdapter);
    }
}

activity_chat.xml

<?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">

    <Button
        android:id="@+id/btnFinish"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/back_button"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true" />

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/my_recycler_view"
        android:scrollbars="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

my_text_view.xml

<?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="match_parent">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:id="@+id/textView" />

</LinearLayout>

Answer 1

Ваш my_text_view.xml должен содержать TextView в качестве корневого элемента в соответствии с вашей реализацией.

Approach-1: Итак, просто измените это, как показано ниже, чтобы решить вашу проблему.

<?xml version="1.0" encoding="utf-8"?>  
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" 
    android:layout_height="30dp" 
    android:id="@+id/textView" />

Approach-2: Или измените onCreateViewHolder реализацию:

onCreateViewHolder(ViewGroup parent, int viewType) { 
// create a new view 
    View v = LayoutInflater.from(parent.getContext()) .inflate(R.layout.my_text_view, parent, false); 
    MyViewHolder vh = new MyViewHolder(v); 
    return vh; 
}

И также измените ViewHolder:

MyViewHolder extends RecyclerView.ViewHolder { 
    // each data item is just a string in this case 
    public TextView textView; 
    public MyViewHolder(View v) { 
        super(v); textView = v; 
        textView = v.findViewById(R.id.textView);
    } 
}