Android 中get请求网络数据详细举例

请求链接 https://api.bilibili.com/x/web-interface/ranking

1.添加网络权限依赖等

implementation 'com.squareup.okhttp3:okhttp:4.9.3'
implementation 'com.google.code.gson:gson:2.8.9'

2.写请求类network

package com.example.myapplication;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.View;
import android.widget.ImageView;

import androidx.annotation.NonNull;

import org.jetbrains.annotations.NotNull;

import java.io.IOException;
import java.io.InputStream;
import java.security.PublicKey;
import java.util.function.BiFunction;

import javax.xml.transform.OutputKeys;

import okhttp3.Cache;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.MediaType;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

public class NetWork {


    private static OkHttpClient client=new OkHttpClient.Builder()
            .build();


    //get请求方式
    public static void get(String url, Callback callback){
        Request request=new Request.Builder()
                .url(url)
                .build();
        client.newCall(request).enqueue(callback);
    }

    //post请求方式
    public static void post(String url,Callback callback,String token,String json){
        RequestBody body=RequestBody.create(MediaType.get(""),json);
        Request request=new Request.Builder()
                .url(url)
                .post(body)
                .build();
        client.newCall(request).enqueue(callback);
    }


    //网络图片下载
    public static void getimg(String url, ImageView img) throws IOException {
        img.setTag(url);
        Request request=new Request.Builder()
                .url(url)
                .build();
        Response response=client.newCall(request).execute();
        Bitmap bitmap= BitmapFactory.decodeStream(response.body().byteStream());
        //判断图片是否重复显示
        img.post(new Runnable() {
            public void run() {
                if (url.equals(img.getTag())) {
                    img.setImageBitmap(bitmap);
                }
            }
        });

    }

}

3.使用listview列表接收接口数据并显示

    <ListView
        android:id="@+id/video_list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

4.编写bean类和适配器adapter 还有adapter页面的子布局

package com.example.myapplication.Bean;

import java.io.Serializable;

public class VideoBean implements Serializable {
    private String img;
    private String name;
    private int id;
    private String time;


    public VideoBean(String img, String name, int id, String time) {
        this.img = img;
        this.name = name;
        this.id = id;
        this.time = time;
    }

    public int getId() {
        return id;
    }

    public String getImg() {
        return img;
    }

    public String getName() {
        return name;
    }

    public String getTime() {
        return time;
    }
}

子布局xml

<?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="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_gravity="center">
    <ImageView
        android:id="@+id/img"
        android:layout_width="150dp"
        android:layout_height="150dp"
        android:layout_gravity="center"/>

        <TextView
            android:id="@+id/name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="15sp"
            android:layout_gravity="center"
            android:layout_marginTop="5dp"/>

        <TextView
            android:id="@+id/time"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="15sp"
            android:layout_gravity="center"
            android:layout_marginTop="5dp"/>
    </LinearLayout>
</LinearLayout>

Listview适配器adapter的编写

package com.example.myapplication.Adapter;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import androidx.constraintlayout.helper.widget.Layer;

import com.example.myapplication.Bean.VideoBean;
import com.example.myapplication.NetWork;
import com.example.myapplication.R;
import com.example.myapplication.ToastUtil;

import java.net.HttpURLConnection;
import java.net.URL;
import java.util.List;

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

public class VideoAdapter extends BaseAdapter {
    private List<VideoBean> list;
    private Context context;


    public VideoAdapter(List<VideoBean> list, Context context) {
        this.list = list;
        this.context = context;
    }

    @Override
    public int getCount() {
        return list.size();
    }

    @Override
    public Object getItem(int position) {
        return position;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView==null){
            convertView= LayoutInflater.from(context).inflate(R.layout.adapter_video,parent,false);
        }
        VideoBean bean=list.get(position);
        ImageView imageView=convertView.findViewById(R.id.img);

        TextView name=convertView.findViewById(R.id.name);
        TextView time=convertView.findViewById(R.id.time);
        name.setText(bean.getName());
        time.setText(bean.getTime());

        //开启子线程去下载图片
        new Thread(new Runnable() {
            public void run() {
                  try {
                      String url=bean.getImg();
                      NetWork.getimg(url,imageView);
                  }catch (Exception e){
                      ToastUtil.show(context,"图片下载失败");
                  }
            }
        }).start();

        return convertView;
    }
}

5.最后数据请求并且填充到listview上面

public class MainActivity extends AppCompatActivity {


    private ListView listView;
    private List<VideoBean>video_data=new ArrayList<>();


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


      listView=findViewById(R.id.video_list);
   NetWork.get("https://api.bilibili.com/x/web-interface/ranking", new Callback() {
            @Override
            public void onFailure(@NotNull Call call, @NotNull IOException e) {
                ToastUtil.show(MainActivity.this,"网络异常");
            }
            public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {
                String json=response.body().string();
                Map<String,Object> map=new Gson().fromJson(json, HashMap.class);
                Map<String,Object>data= (Map<String, Object>) map.get("data");
                List<Map<String, Object>>list= (List<Map<String, Object>>) data.get("list");
                runOnUiThread(new Runnable() {
                    public void run() {
                        for (Map<String,Object>list:list){
                            Integer id;
                            try {
                                id=Integer.valueOf(list.get("aid").toString());
                            }catch (Exception e){
                                id=0;
                            }
                            VideoBean bean=new VideoBean(list.get("pic").toString(),
                                    list.get("title").toString(), id,
                                    list.get("duration").toString());
                            video_data.add(bean);
                        }
                        listView.setAdapter(new VideoAdapter(video_data,MainActivity.this));
                        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                            @Override
                            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                                VideoBean bean=video_data.get(position);
                                 ToastUtil.show(MainActivity.this,bean.getId()+"");
                            }
                        });

                    }
                });
            }
        });


     }
}

6.写一个ToastUtil工具类（判断是否需要在子线程发送）

package com.example.myapplication;

import android.content.Context;
import android.os.Handler;
import android.os.Looper;
import android.widget.Toast;

import androidx.annotation.NonNull;

import org.jetbrains.annotations.NotNull;

public class ToastUtil {
    private static Handler handler=new Handler(Looper.getMainLooper());

  public static void show(Context ctx,String txt){
      if (Looper.myLooper()==Looper.getMainLooper()){
          Toast.makeText(ctx, txt, Toast.LENGTH_SHORT).show();
      }else {
          handler.sendEmptyMessage(0);
          handler.post(new Runnable() {
              @Override
              public void run() {
                  Toast.makeText(ctx, txt, Toast.LENGTH_SHORT).show();
              }
          });

      }
  }
}