Question

在我的MainActivity中，我为id getclients和getemployees的按钮设置了监听器。如果单击一个按钮，我会使用HttpGet从我的服务器接收json数据（这很好）。

但是，在onPostExecute中，您可以看到我创建了一个getEmployees（class）实例。该类应该评估来自JSON的数据并创建员工视图。

MainActivity.java：

package learn2crack.listview;

import java.util.ArrayList;
import java.util.HashMap;

import learn2crack.listview.library.JSONParser;
import ontime.employees.getEmployees;

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

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

public class MainActivity extends Activity {
    ListView list;
    TextView name;
    TextView address;
    TextView status;
    Button BtnGetClients;
    Button BtnGetEmployees;
    getEmployees employees;
    ArrayList<HashMap<String, String>> oslist = new ArrayList<HashMap<String, String>>();

    JSONArray android = null;

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

        setContentView(R.layout.activity_main);
        oslist = new ArrayList<HashMap<String, String>>();
        BtnGetClients = (Button)findViewById(R.id.getclients);
        BtnGetClients.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                 String url = "http://portal.ontimebemanning.no/api/json/clients/";
                 new JSONParse(url, "getClients", "clients").execute();
            }
        });
        BtnGetEmployees = (Button)findViewById(R.id.getemployees);
        BtnGetEmployees.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                 String url = "http://portal.ontimebemanning.no/api/json/employees/";
                 new JSONParse(url, "getEmployees", "employees").execute();
            }
        });

    }

    private class JSONParse extends AsyncTask<String, String, JSONObject> {
        public String get_url;
        public String get_view;
        public String get_tag;       
        public JSONParse(String Url, String view, String tag){
            get_url = Url;
            get_tag = tag;
            get_view = view;
        }


        @Override
        protected JSONObject doInBackground(String... args) {
            JSONParser jParser = new JSONParser();
            // Getting JSON from URL
            JSONObject json = jParser.getJSONFromUrl(get_url);
            return json;            
        }

        @Override
        protected void onPostExecute(JSONObject json) { 
             employees = new getEmployees();
             try {
                // Getting JSON Array from URL
                android = json.getJSONArray(get_tag); 
                for(int i = 0; i < android.length(); i++){
                    JSONObject c = android.getJSONObject(i);
                    Log.d( "current", "Initiating getEmployees");
                    employees.createView( c );

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


        }
    }

}

getEmployees.java：

package ontime.employees;

import java.util.ArrayList;
import java.util.HashMap;

import learn2crack.listview.MainActivity;
import learn2crack.listview.R;

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

import android.os.Bundle;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

public class getEmployees extends MainActivity {

    ArrayList<HashMap<String, String>> oslist = new ArrayList<HashMap<String, String>>();
    ListView list;
    TextView name;
    TextView address;
    TextView status;

    public String putname, putaddress, putstatus;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Log.d("current", "OnCreate...");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        name = (TextView)findViewById(R.id.name);
        address = (TextView)findViewById(R.id.address);
        status = (TextView)findViewById(R.id.status);   
        list=(ListView)findViewById(R.id.list);
        oslist = new ArrayList<HashMap<String, String>>();
    }

    public getEmployees() {
        super();
    }    

    public void createView( JSONObject jSon ){ 
        try {
            String putname = jSon.getString("firm");
            String putaddress = jSon.getString("address");
            String putstatus = jSon.getString("status");        
        } catch (JSONException e) {
            Log.e( "Current", e.getMessage());
        }
        Log.d("current", "HashMap");
        HashMap<String, String> map = new HashMap<String, String>();

        map.put("firstname", putname);  
        map.put("address", putaddress);
        map.put("status", putstatus);       
        oslist.add(map);
        Log.d("current", "ListAdapter");
        try{
            ListAdapter adapter = new SimpleAdapter(getEmployees.this, oslist,
                    R.layout.list_v,
                    new String[] { "firstname","address", "status" }, new int[] {
                            R.id.name,R.id.address, R.id.status});
            list.setAdapter(adapter);
        }
        catch(Exception e){
            Log.e("current",e.getMessage());
        }
        Log.d("current", "ListAdapter");


    }

}

LogCat的输出：

10-23 08:14:57.690: D/current(14936): Initiating getEmployees
10-23 08:14:57.690: D/current(14936): HashMap
10-23 08:14:57.690: D/current(14936): ListAdapter
10-23 08:14:57.690: E/current(14936): System services not available to Activities before onCreate()

所以，我认为我的代码在ListAdapter / SimpleAdapter上破坏了，它试图修改R对象/视图。我也试过在getEmployees中的oncreate函数中添加一个Log.d，但这不会被触发，所以我认为这可能是我的问题的一部分，也就是说它没有设置当前类的视图。

非常感谢任何帮助。

从子类修改R / view

0 个答案: