Android | RecyclerView不起作用

Question

I want to create a RecyclerView with a few CardView s in it. For this I start a Thread in the onCreate of my Activity. There I get the data from my server and put this in a list. Then I create the Adapter for the RecyclerView, but it doesn't work. Here is my code:

Here I create the adapter and it should fill all CardView s in:

ListAdapter adapter = new ListAdapter(posts);
RecyclerView rv = (RecyclerView)findViewById(R.id.post_list);
rv.setAdapter(adapter);

Here is my adapter class

public class ListAdapter extends RecyclerView.Adapter<ListAdapter.PostViewHolder> {

List<Post> posts;

public ListAdapter(List<Post> posts) {
    Log.d("ListAdapter", "");
    this.posts = posts;
}

@Override
public int getItemCount() {
    Log.d("getItemCount", "");
    return posts.size();
}

@Override
public PostViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    Log.d("onCreateView", "");
    View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.insert_layout, viewGroup, false);
    PostViewHolder pvh = new PostViewHolder(v);
    return pvh;
}

@Override
public void onBindViewHolder(PostViewHolder postViewHolder, int i) {
    Log.d("onBindView", "");
    postViewHolder.username.setText(posts.get(i).getUsername());
    postViewHolder.text.setText(posts.get(i).getText());
    postViewHolder.time.setText(Long.toString(posts.get(i).getTime()));
    postViewHolder.postPhoto.setImageResource(posts.get(i).returnIMG());
}

@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
    Log.d("onAttached", "");
    super.onAttachedToRecyclerView(recyclerView);
}


public static class PostViewHolder extends RecyclerView.ViewHolder {
    CardView cv;
    TextView username;
    TextView time;
    TextView text;
    ImageView postPhoto;

    PostViewHolder(View itemView) {
        super(itemView);
        Log.d("PostViewHolder", "");
        cv = (CardView) itemView.findViewById(R.id.cv);
        username = (TextView) itemView.findViewById(R.id.usernameText);
        time = (TextView) itemView.findViewById(R.id.timeText);
        text = (TextView) itemView.findViewById(R.id.textText);
        postPhoto = (ImageView) itemView.findViewById(R.id.postPhoto);
    }
}

Here is my recyclerview:

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


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

and my cardview:

<android.support.v7.widget.CardView android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/cv"
    xmlns:android="http://schemas.android.com/apk/res/android">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            >

            <ImageView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/postPhoto"
                android:layout_alignParentLeft="true"
                android:layout_alignParentTop="true"
                />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/textText"
                android:layout_alignParentTop="true"
                android:textSize="30sp"
                />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/usernameText"/>
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/timeText"/>

        </RelativeLayout>

    </android.support.v7.widget.CardView>

And here the 2 errors:

E/RecyclerView: No adapter attached; skipping layout E/RecyclerView: No layout manager attached; skipping layout

But I do both, dont't I?

Answer 1

set the LayoutManager first.

From your code :

ListAdapter adapter = new ListAdapter(posts);
RecyclerView rv = (RecyclerView)findViewById(R.id.post_list);
rv.setHasFixedSize(true);

LinearLayoutManager layoutManager = new LinearLayoutManager(this);
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
rv.setLayoutManager(layoutManager);

rv.setAdapter(adapter);

Hope this will help you!!..