Retrofit解析网络json

懒得一大堆废话，说完实现最终目标，直接进入正题操作，直接上代码，看使用方法

实现目标：用Retrofit解析网络json，放到RecyclerView中

第一步，写好布局文件以及item，我这里用的RecyclerView,不知道RecyclerView就点进去看看，解析出来的格式就是，一个图片，一个文字，直接看布局文件和item。

加入依赖

implementation 'com.squareup.retrofit2:retrofit:2.3.0'
implementation 'com.squareup.retrofit2:converter-gson:2.3.0'

加入RecyclerView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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">

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

</LinearLayout>

item:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="0dp"
        android:layout_height="120dp"
        android:layout_weight="2" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="120dp"
        android:layout_weight="3"
        android:gravity="center" />

</LinearLayout>

之后写一个RecyclerView的适配器，用具加入图片和文字

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.MyHolder> {
    
    private Context context;
    private List<JavaBean.DataBean> data;//数据源集合

    //构造方法
    public RecyclerViewAdapter(Context context, List<JavaBean.DataBean> data) {
        this.context = context;
        this.data = data;
    }

    @NonNull
    @Override
    public MyHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View inflate = LayoutInflater.from(context).inflate(R.layout.item, viewGroup, false);
        return new MyHolder(inflate);
    }

    @Override
    public void onBindViewHolder(@NonNull MyHolder myHolder, int i) {
        Picasso.with(context).load(data.get(i).getPic()).into(myHolder.imageView);//加入图片
        myHolder.textView.setText(data.get(i).getTitle());//加入名字
    }

    @Override
    public int getItemCount() {
        return data.size();//返回集合size
    }

    public class MyHolder extends RecyclerView.ViewHolder {

        ImageView imageView;
        TextView textView;

        public MyHolder(@NonNull View itemView) {
            super(itemView);
            imageView = itemView.findViewById(R.id.imageView);
            textView = itemView.findViewById(R.id.textView);
        }
    }
}

提供网络字符串:https://1604a.com/data/ymdx.json

接下来是重点，如何通过Retrofit获取网络数据，看java代码

Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("https://1604a.com/data/")//网络数据源，网址前半段
                .addConverterFactory(GsonConverterFactory.create())//解析
                .build();

创建接口，get请求方式，写入网址的后半段，即最后一个“/”之后的字符，像下面这么写

public interface MyInterface {
    @GET("ymdx.json")
    Call<JavaBean> gerRequest();
}

接着使用这个接口

MyInterface myInterface = retrofit.create(MyInterface.class);
Call<JavaBean> call = myInterface.gerRequest();

接下来写Call的一个方法enqueue，注释有详细标明

call.enqueue(new Callback<JavaBean>() {

            //成功
            @Override
            public void onResponse(Call<JavaBean> call, Response<JavaBean> response) {
                //解析添加到创建的集合
                arrayList = response.body().getData();

                recyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL));
                recyclerView.setItemAnimator(new DefaultItemAnimator());//RecyclerView动画：默认动画
                //使用适配器
                recyclerView.setAdapter(new RecyclerViewAdapter(MainActivity.this,arrayList));


            }

            //失败
            @Override
            public void onFailure(Call<JavaBean> call, Throwable t) {
                Toast.makeText(MainActivity.this, "请求失败", Toast.LENGTH_SHORT).show();
            }
        });

看一下完整的java代码

public class MainActivity extends AppCompatActivity {

    private List<JavaBean.DataBean> arrayList;
    private RecyclerView recyclerView;

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

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("https://1604a.com/data/")
                .addConverterFactory(GsonConverterFactory.create())
                .build();

        MyInterface myInterface = retrofit.create(MyInterface.class);
        Call<JavaBean> call = myInterface.gerRequest();

        call.enqueue(new Callback<JavaBean>() {

            //成功
            @Override
            public void onResponse(Call<JavaBean> call, Response<JavaBean> response) {
                //解析添加到创建的集合
                arrayList = response.body().getData();

                recyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL));
                recyclerView.setItemAnimator(new DefaultItemAnimator());
                //使用适配器
                recyclerView.setAdapter(new RecyclerViewAdapter(MainActivity.this,arrayList));


            }

            //失败
            @Override
            public void onFailure(Call<JavaBean> call, Throwable t) {
                Toast.makeText(MainActivity.this, "请求失败", Toast.LENGTH_SHORT).show();
            }
        });


    }

    private void initView() {
        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
    }
}

》》》》快速实例化控件《《《《

最重要的一步，加入网络权限：<uses-permission android:name="android.permission.INTERNET"/>

效果浏览：

Retrofit解析网络json

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