Question

我正在尝试使用json从数据库加载数据并将其显示在片段的listview中。我有两个类，一个叫做下载器，另一个叫做perser。我想要的是将这些数据添加到fragmnet中的listview。

我怎样才能实现这一点，因为它在content_mani中运行良好，但我想让它分段

import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.ListView;
import android.widget.Toast;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import info.androidhive.materialtabs.fragments.OneFragment;

/**
 * Created by GEORGE on 25/06/2016.
 */
public class Downloader extends AsyncTask<Void ,Integer,String>{
    Context c;
    String urladdress;
    ListView lv;
    ProgressDialog progressDialog;

    public Downloader(MainActivity context, ListView listView, String urladdress) {
        this.c = context;
        this.urladdress = urladdress;
        this.lv = listView;
    }
// before the job start
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog=new ProgressDialog(c);
        progressDialog.setTitle("fetch data");
        progressDialog.setMessage("fetching data.....please wait");
        progressDialog.show();
    }

    @Override
    protected String doInBackground(Void... params) {
        String data=downloadData();
        return data;
    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        super.onProgressUpdate(values);
    }

    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        progressDialog.dismiss();
        if(s!=null){
    Parser p=new Parser(c,s,lv);
           p.execute();

        }else {
            Toast.makeText(c,"Unable to download data",Toast.LENGTH_LONG).show();

        }
    }
    private String downloadData(){
        InputStream inputStream=null;
        String line=null;
        try{
            URL url=new URL(urladdress);
            HttpURLConnection httpURLConnection=(HttpURLConnection) url.openConnection();
            inputStream=new BufferedInputStream(httpURLConnection.getInputStream());
            BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(inputStream));
            StringBuffer stringBuffer=new StringBuffer();
            if (bufferedReader!=null)
            {
                while ((line=bufferedReader.readLine())!=null)
                {
                    stringBuffer.append(line+"\n");

                }
            }else
            {
                return null;
            }
            return  stringBuffer.toString();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
        catch (IOException e) {
            e.printStackTrace();
        }       finally {
            if (inputStream!=null)
            {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return  null;
    }
}
 and



package info.androidhive.materialtabs.activity;


import android.app.*;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.*;
import info.androidhive.materialtabs.R;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.*;


public class Parser extends AsyncTask<Void,Integer,Integer> {
    Context c;
    ListView lv;
    String data;
    ArrayList<String> users=new ArrayList<>();
    ProgressDialog pd;

    public Parser(Context c, String data, ListView lv) {
        this.c = c;
        this.data = data;
        this.lv = lv;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pd=new ProgressDialog(c);
        pd.setTitle("parser");
        pd.setMessage("parsing....please wait");
        pd.show();
    }

    @Override
    protected Integer doInBackground(Void... params) {
        return  this.perse();

    }

    @Override
    protected void onPostExecute(Integer integer) {
        super.onPostExecute(integer);

        if(integer==1){
  ArrayAdapter<String> adapter=new ArrayAdapter<String>(c, android.R.layout.simple_list_item_1,users);
            lv.setAdapter(adapter);
        }
        else {
            Toast.makeText(c,"Unable to perse",Toast.LENGTH_LONG).show();
        }
        pd.dismiss();
    }
private  int perse(){
    try{
        JSONArray ja=new JSONArray(data);
        JSONObject jo=null;
        users.clear();
        for (int i=0;i<ja.length();i++){
            jo=ja.getJSONObject(i);
            String name=jo.getString("Category_name");
            String id=jo.getString("idcategories");
            users.add(name);
        }

        return 1;

    } catch (JSONException e) {
        e.printStackTrace();
    }
    return 0;
}

}





package info.androidhive.materialtabs.fragments;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ListView;

import info.androidhive.materialtabs.R;
import info.androidhive.materialtabs.activity.Downloader;


public class OneFragment extends Fragment{
    Button btn_categories;
    String urladdress="http://192.168.0.107/android/users.php";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
      View  view =inflater.inflate(R.layout.fragment_one, container, false);
        btn_categories = (Button) view.findViewById(R.id.btn_categories);
        final ListView lv = (ListView) view.findViewById(R.id.lv);
        //final Downloader downloader=new Downloader(this, lv, urladdress);
        //downloader.execute();

        return view;
    }

}

Answer 1

我假设您可以从服务器正确检索JSON文件。以下代码是我为我的应用程序所做的。

class LoadDataAsyn extends AsyncTask<Void,Void,Void>{
    JSONArray data;
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // you can use ProgressDialog to indicate request start;
    }

    @Override
    protected Void doInBackground(Void... params) {
        //User is a custom class and contactlist return a Jsonarray
        data = new User().ContactList();
        return null;
    }

    @Override
    protected void onPostExecute(Void aVoid) {
        super.onPostExecute(aVoid);
        if (data!=null){
            if (adapter==null){
                adapter = new CustomAdapter(context.this,data);
                listView.setAdapter(adapter);
            }else{
                adapter.Refresh(data);
            }
        }
    }
}

我的代码中的想法是直接将JSON数组传递给适配器在我的自定义类中：

public class CustomerAdapter extends BaseAdapter {
Context context;
JSONArray data;
public SearchSchoolAdapter (Context context,JSONArray data){
    this.context= context;
    this.data = data;
}
@Override
public int getCount() {
    if (data!=null){
        return data.length();
    }
    return 0;
}

@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) {
    OneHolder holder;
    if (convertView == null||!(convertView.getTag() instanceof OneHolder)){
        convertView = LayoutInflater.from(context).inflate(R.layout.listrow_layout,null);
        holder = new OneHolder();
        holder.image = (ImageView)convertView.findViewById(R.id.pic);
        holder.full =(TextView)convertView.findViewById(R.id.fullname);
        convertView.setTag(holder);
    }else{
        holder = (OneHolder)convertView.getTag();
    }
    if (data!=null&&data.length()>position){
        try {
            JSONObject one = data.getJSONObject(position);
            holder.full.setText(one.getString("name"));
        } catch (JSONException e) {
            e.printStackTrace();
        }

    }
    return convertView;
}
class OneHolder {
    ImageView image;
    TextView full,abb;
}
public void Refersh(JSONArray data){
    this.data=data;
    notifyDataSetChanged();
}

} 我不知道这是不是你要问的，希望它可以帮助你。

使用json显示mysql中的数据到listview中的listview

1 个答案: