android - 回收站 View 不显示任何内容

Question

我一直在制作一个使用 RecyclerView 的应用程序，但它没有显示任何东西..为什么没有显示回收器 View 的内容。我的代码如下所示

item_contact.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:paddingBottom="10dp"
    android:paddingTop="10dp">

    <TextView
        android:id="@+id/contact_name"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

    <Button
        android:id="@+id/message_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingLeft="16dp"
        android:paddingRight="16dp"
        android:textSize="10sp" />
</LinearLayout>

联系人适配器.java

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

import java.util.List;
public class ContactsAdapter extends RecyclerView.Adapter<ContactsAdapter.ViewHolder> {

    private List<Contact> mContacts;
    public ContactsAdapter(List<Contact> contacts) {
        mContacts = contacts;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        Context context = parent.getContext();
        LayoutInflater inflater = LayoutInflater.from(context);
        View contactView = inflater.inflate(R.layout.item_contact, parent, false);
        ViewHolder viewHolder = new ViewHolder(contactView);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(ViewHolder viewHolder, int position) {
        Contact contact = mContacts.get(position);

        TextView textView = viewHolder.nameTextView;
        textView.setText(contact.getName());

        Button button = viewHolder.messageButton;

        if (contact.isOnline()) {
            button.setText("Message");
            button.setEnabled(true);
        } else {
            button.setText("Offline");
            button.setEnabled(false);
        }
    }

    @Override
    public int getItemCount() {
        return mContacts.size();
    }
    public static class ViewHolder extends RecyclerView.ViewHolder {
        public TextView nameTextView;
        public Button messageButton;
        public ViewHolder(View itemView) {
            super(itemView);
            nameTextView = (TextView) itemView.findViewById(R.id.contact_name);
            messageButton = (Button) itemView.findViewById(R.id.message_button);
        }
    }
}

联系人.java

import java.util.ArrayList;
import java.util.List;

public class Contact {
    private String mName;
    private boolean mOnline;

    public Contact(String name, boolean online) {
        mName = name;
        mOnline = online;
    }

    public String getName() {
        return mName;
    }

    public boolean isOnline() {
        return mOnline;
    }

    private static int lastContactId = 0;

    public static List<Contact> createContactsList(int numContacts) {
        List<Contact> contacts = new ArrayList<Contact>();

        for (int i = 1; i <= numContacts; i++) {
            contacts.add(new Contact("Person " + ++lastContactId, i <= numContacts / 2));
        }

        return contacts;
    }
}

主 Activity .java

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_home, container, false);
    RecyclerView rvContacts = (RecyclerView) rootView.findViewById(R.id.view);
    ContactsAdapter adapter = new ContactsAdapter(Contact.createContactsList(20));
    rvContacts.setAdapter(adapter);
    rvContacts.setLayoutManager(new LinearLayoutManager(getContext()));

请帮帮我

Answer 1

我编写的代码非常好并且工作没有任何问题，在我的主要代码中 RecyclearView 高度为零，这就是我没有得到输出的原因。