如何使用凌空机器人实现ListView [英] How to implement a listview using volley android

问题描述

我正在开发一个应用程序，该应用程序可获取API的客户端列表，并且需要在列表视图中显示它，我正在使用volley，但我尝试做的是以下操作，但它不起作用:

I'm developing an app that grabs a list of clients of an API, and I need to show it in a listview, I'm using volley and what I tried to do is the following, but it's not working:

 public ListView txtDisplay;

@Override
        protected Boolean doInBackground(Void... params) {


            try {


                txtDisplay = (Listview) findViewById(R.id.listView);

                String url = "http://192.168.1.1/rep-mais-api/api";


                 JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.GET,
                        url, null,
                        new Response.Listener<JSONObject>() {

                            @Override
                            public void onResponse(JSONObject response) {


                                findViewById(R.id.progressBar1).setVisibility(View.GONE);
                            }
                        }, new Response.ErrorListener() {

                    @Override
                    public void onErrorResponse(VolleyError error) {
                        VolleyLog.d("Error: " + error.getMessage());


                    }
                })

ActivityMain.xml:

The ActivityMain.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <android.support.v4.view.ViewPager
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/pager" />
    <TextView
        android:id="@+id/txtDisplay"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />

    <ListView
  android:layout_width="wrap_content"
   android:layout_height="wrap_content"
    android:id="@+id/listView"
  android:layout_alignParentTop="true" android:layout_alignParentLeft="true"/>
    <ProgressBar
        android:id="@+id/progressBar1"
        style="?android:attr/progressBarStyleLarge"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true" />
</RelativeLayout>

推荐答案

使用此示例，解决了我的情况

Using this example, solved my case

import android.app.ProgressDialog;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONObject;

import java.util.ArrayList;

public class MainActivity extends Activity {

    private String TAG = this.getClass().getSimpleName();
    private ListView lstView;
    private RequestQueue mRequestQueue;
    private ArrayList<NewsModel> arrNews ;
    private LayoutInflater lf;
    private VolleyAdapter va;
    private ProgressDialog pd;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        lf = LayoutInflater.from(this);


        arrNews = new ArrayList<NewsModel>();
        va = new VolleyAdapter();

        lstView = (ListView) findViewById(R.id.listView);
        lstView.setAdapter(va);
        mRequestQueue =  Volley.newRequestQueue(this);
        String url = "http://pipes.yahooapis.com/pipes/pipe.run?_id=giWz8Vc33BG6rQEQo_NLYQ&_render=json";
        pd = ProgressDialog.show(this,"Please Wait...","Please Wait...");
        try{
            Thread.sleep(2000);
        }catch(Exception e){

            }
        JsonObjectRequest jr = new JsonObjectRequest(Request.Method.GET,url,null,new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                Log.i(TAG,response.toString());
                parseJSON(response);
                va.notifyDataSetChanged();
                pd.dismiss();
;            }
        },new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.i(TAG,error.getMessage());
            }
        });
        mRequestQueue.add(jr);



    }

    private void parseJSON(JSONObject json){
        try{
            JSONObject value = json.getJSONObject("value");
            JSONArray items = value.getJSONArray("items");
            for(int i=0;i<items.length();i++){

                    JSONObject item = items.getJSONObject(i);
                    NewsModel nm = new NewsModel();
                    nm.setTitle(item.optString("title"));
                    nm.setDescription(item.optString("description"));
                    nm.setLink(item.optString("link"));
                    nm.setPubDate(item.optString("pubDate"));
                    arrNews.add(nm);
            }
        }
        catch(Exception e){
            e.printStackTrace();
        }


    }


    class NewsModel{
        private String title;
        private String link;
        private String description;
        private String pubDate;

        void setTitle(String title) {
            this.title = title;
        }

        void setLink(String link) {
            this.link = link;
        }

        void setDescription(String description) {
            this.description = description;
        }

        void setPubDate(String pubDate) {
            this.pubDate = pubDate;
        }

        String getLink() {
            return link;
        }

        String getDescription() {
            return description;
        }

        String getPubDate() {
            return pubDate;
        }

        String getTitle() {

            return title;
        }
    }


    class VolleyAdapter extends BaseAdapter{

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

        @Override
        public Object getItem(int i) {
            return arrNews.get(i);
        }

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

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            ViewHolder vh ;
           if(view == null){
               vh = new ViewHolder();
               view = lf.inflate(R.layout.row_listview,null);
               vh.tvTitle = (TextView) view.findViewById(R.id.txtTitle);
               vh.tvDesc = (TextView) view.findViewById(R.id.txtDesc);
               vh.tvDate = (TextView) view.findViewById(R.id.txtDate);
               view.setTag(vh);
          }
            else{
               vh = (ViewHolder) view.getTag();
           }

            NewsModel nm = arrNews.get(i);
            vh.tvTitle.setText(nm.getTitle());
            vh.tvDesc.setText(nm.getDescription());
            vh.tvDate.setText(nm.getPubDate());
            return view;
        }

         class  ViewHolder{
            TextView tvTitle;
             TextView tvDesc;
             TextView tvDate;

        }

    }
}

来源

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