Chào anh Long, em đang học lập trình Android theo video của Kteam. Đến bài 15: Json và WebAPI, em có làm theo và chạy thử nhưng nó toàn hiện lên 0. Em không biết vấn đề là gì. Mong anh và mọi người giúp đỡ em. Em cảm ơn anh

Bài 15: Json và WebAPI

Activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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=".MainActivity">
    <androidx.recyclerview.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent" android:id="@+id/rvUsers"></androidx.recyclerview.widget.RecyclerView>
</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.Java:

package com.example.jsonexample;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;
import android.util.Log;
import android.widget.LinearLayout;

import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;
import com.squareup.moshi.Types;

import java.io.IOException;
import java.lang.reflect.Array;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        RecyclerView recyclerView=(RecyclerView)findViewById(R.id.rvUsers);
        recyclerView.setHasFixedSize(true);
        LinearLayoutManager layoutManager=new LinearLayoutManager(this, LinearLayoutManager.VERTICAL,false);
        recyclerView.setLayoutManager(layoutManager);
        // Khởi tạo OkHttpClient để lấy dữ liệu.
        OkHttpClient client = new OkHttpClient();

        // Khởi tạo Moshi adapter để biến đổi json sang model java (ở đây là User)
        Moshi moshi = new Moshi.Builder().build();
        Type usersType = Types.newParameterizedType(List.class, User.class);
        final JsonAdapter<ArrayList<User>> jsonAdapter = moshi.adapter(usersType);

        // Tạo request lên server.
        Request request = new Request.Builder()
                .url("https://api.github.com/users")
                .build();

        // Thực thi request.
        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                Log.e("Error", "Network Error");
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {

                // Lấy thông tin JSON trả về. Bạn có thể log lại biến json này để xem nó như thế nào.
                String json = response.body().string();
                final ArrayList<User> users = jsonAdapter.fromJson(json);

                // Cho hiển thị lên RecyclerView.
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        recyclerView.setAdapter(new UserAdapter(users, getApplicationContext()));
                    }
                });
            }
        });
    }
}

User.java:

package com.example.jsonexample;

public class User {
    public String _Login;
    public int _ID;
    public String _Avatar_url;
}

item_user.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <ImageView
        android:layout_width="200dp"
        android:layout_height="200dp" android:id="@+id/image"></ImageView>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" android:id="@+id/tvName" android:layout_toRightOf="@id/image" android:text="Name"></TextView>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" android:id="@+id/tvID" android:text="ID" android:layout_below="@id/tvName" android:layout_toRightOf="@id/image"></TextView>
</RelativeLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

UserAdapter.java:

package com.example.jsonexample;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.squareup.picasso.Picasso;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.List;

public class UserAdapter extends RecyclerView.Adapter<UserAdapter.ViewHolder> {
    public ArrayList<User> getUserList() {
        return UserList;
    }

    public void setUserList(ArrayList<User> userList) {
        UserList = userList;
    }

    public Context getContext() {
        return context;
    }

    public void setContext(Context context) {
        this.context = context;
    }

    ArrayList<User> UserList;
    Context context;
    public UserAdapter(ArrayList<User> pUser, Context pContext)
    {
        UserList=pUser;
        context=pContext;
    }
    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater layoutInflater=LayoutInflater.from(parent.getContext());
        View itemview=layoutInflater.inflate(R.layout.item_user,parent,false);
        return new ViewHolder(itemview);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        User u=UserList.get(position);
        Picasso.with(context).load(u._Avatar_url).into(holder.imageView);
        holder.textViewName.setText(u._Login);
        holder.textViewID.setText(String.valueOf(u._ID));
    }

    @Override
    public int getItemCount() {
        return UserList.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        ImageView imageView;
        TextView textViewName;
        TextView textViewID;
        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            imageView=(ImageView)itemView.findViewById(R.id.image);
            textViewName=(TextView)itemView.findViewById(R.id.tvName);
            textViewID=(TextView)itemView.findViewById(R.id.tvID);
        }
    }
}

AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.jsonexample">
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.JsonExample">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>