ListView以及AsyncTask显示

主页面

package com.example.myapplication;

import android.content.Context;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ListView;

import com.google.gson.Gson;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
private ListView lv;
private MyActivity myActivity;
private List<User.DataBean.PcFeedFocusBean> list = new ArrayList<>();
String auiUri = “https://www.toutiao.com/api/pc/focus/”;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv=findViewById(R.id.lv);
myActivity = new MyActivity(this, list);
lv.setAdapter(myActivity);
new lian().execute(auiUri);
}
class lian extends AsyncTask<String,Void,ArrayList<User.DataBean.PcFeedFocusBean>>
{

        @Override
        protected ArrayList<User.DataBean.PcFeedFocusBean> doInBackground(String... strings) {
            try {
                URL url=new URL(strings[0]);
                HttpURLConnection urlConnection= (HttpURLConnection) url.openConnection();
                if (urlConnection.getResponseCode()==200){
                    InputStream inputStream = urlConnection.getInputStream();
                    Gson gson=new Gson();
                    User user = gson.fromJson(new BufferedReader(new InputStreamReader(inputStream)), User.class);
                    List<User.DataBean.PcFeedFocusBean> pc_feed_focus = user.getData().getPc_feed_focus();
                    return (ArrayList<User.DataBean.PcFeedFocusBean>) pc_feed_focus;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(ArrayList<User.DataBean.PcFeedFocusBean> pcFeedFocusBeans) {
            super.onPostExecute(pcFeedFocusBeans);
            myActivity.setList(pcFeedFocusBeans);
            list.addAll(pcFeedFocusBeans);
        }
    }

}
//页面
package com.example.myapplication;

import android.content.Context;
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 java.util.List;

public class MyActivity extends BaseAdapter {
private Context context;
private List<User.DataBean.PcFeedFocusBean> list;

public MyActivity(Context context, List<User.DataBean.PcFeedFocusBean> list) {
    this.context = context;
    this.list = list;
}

public void setList(List<User.DataBean.PcFeedFocusBean> list) {
    this.list = list;
    notifyDataSetChanged();
}

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

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

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder viewHolder;
    if (convertView==null){
        viewHolder=new ViewHolder();
        convertView=LayoutInflater.from(context).inflate(R.layout.shu,parent,false);
        viewHolder.name=convertView.findViewById(R.id.name);
        viewHolder.time=convertView.findViewById(R.id.time);
        viewHolder.img=convertView.findViewById(R.id.img);
        convertView.setTag(viewHolder);
    }else{
        viewHolder=(ViewHolder) convertView.getTag();
    }
    viewHolder.name.setText(list.get(position).getTitle());
    return convertView;
}
class ViewHolder{
    TextView name,time;
    ImageView img;
}

}