利用PullToRefresh实现上拉下拉

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最新推荐文章于 2024-11-01 15:21:01 发布

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本文链接：https://blog.youkuaiyun.com/weixin_40060410/article/details/78012578

本教程介绍如何使用Android创建一个能够从API获取新闻数据并显示在列表视图的应用。通过PullToRefreshLayout实现下拉刷新功能，并利用Universal Image Loader加载图片。应用还包括了自定义适配器以提高列表展示效率。

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package com.example.week3;

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

import com.jwenfeng.library.pulltorefresh.BaseRefreshListener;
import com.jwenfeng.library.pulltorefresh.PullToRefreshLayout;

public class MainActivity extends AppCompatActivity {

    private PullToRefreshLayout pull;
    private ListView mlv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        pull = (PullToRefreshLayout) findViewById(R.id.pull);
        mlv = (ListView) findViewById(R.id.mlv);

        GetData data=  new GetData();
        data .data(MainActivity.this,mlv);


        pull.setRefreshListener(new BaseRefreshListener() {
            @Override
            public void refresh() {

            }

            @Override
            public void loadMore() {

            }
        });
    }
}-----------------------------
适配器
package com.example.week3;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import com.nostra13.universalimageloader.core.ImageLoader;
import java.util.List;





public class MyAdapter extends BaseAdapter {

    private List<JavaBean.NewslistBean> list;
    private Context context;
    private ViewHolder holder=null;

    public MyAdapter(List<JavaBean.NewslistBean> list, Context context) {
        this.list = list;
        this.context = context;
    }



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

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

    @Override
    public long getItemId(int i) {
        return 0;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        if (view==null){
            view=View.inflate(context,R.layout.listview_item,null);
            holder = new ViewHolder();
            holder.titl = view.findViewById(R.id.titl);
            holder.tim = view.findViewById(R.id.tim);
            holder.img= view.findViewById(R.id.img);
            view.setTag(holder);
        }else{
            holder=(ViewHolder)view.getTag();
        }
        holder.titl.setText(list.get(i).getTitle());
        holder.tim.setText(list.get(i).getCtime());

        ImageLoader.getInstance().displayImage(list.get(i).getPicUrl(), holder.img);
        return view;
    }
    class ViewHolder{
        TextView titl;
        TextView tim;
        ImageView img;

    }
}
-------------------------------------------------------------------
package com.example.week3;


import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.ListView;

import com.google.gson.Gson;

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




public class GetData {

     public GetData data(final Context context, final ListView listView){
         new AsyncTask<String, Integer, String>() {

             @Override
             protected String doInBackground(String... strings) {
                 String str="";
                 try {
                     URL url = new URL("https://api.tianapi.com/wxnew/?key=8d6e3228d25298f13af4fc40ce6c9679&num=10");
                     //打开链接
                     HttpURLConnection conne=(HttpURLConnection) url.openConnection();

                     //设置时间
                     conne.setRequestMethod("GET");
                     conne.setReadTimeout(5000);
                     conne.setConnectTimeout(5000);
                     //获取响应码且判断其返回值是否是200
                     int responseCode = conne.getResponseCode();
                     Log.d("zzz","==================================================================================="+responseCode);
                     if (responseCode==200) {
                         InputStream in = conne.getInputStream();
                         byte[] by= new byte[1024];
                         int len=0;

                         while ((len=in.read(by))!=-1) {

                             str+=new String(by,0,len);

                         }

                         Log.d("zzz", "doInBackground霍长生: "+str);
                     }
                 } catch (Exception e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }
                 return str;
             }

             @Override
             protected void onPostExecute(String result) {
                 Gson gson = new Gson();
                 JavaBean bean = gson.fromJson(result, JavaBean.class);
                 List<JavaBean.NewslistBean> list = bean.getNewslist();//返回集合
                 MyAdapter myadpader = new MyAdapter(list,context);
                 listView.setAdapter(myadpader);
             }
         }.execute();

         return null;
     }
}
-----------------------------------------------------------------------
package com.example.week3;

import android.app.Application;

import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import com.nostra13.universalimageloader.core.ImageLoader;
/**
 * Created by 霍长生 on 2017/9/17 0017.
 */


public class App extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        ImageLoaderConfiguration configuration=ImageLoaderConfiguration.createDefault(this);
        ImageLoader.getInstance().init(configuration);
    }
}