java - onItemClickListener 的应用程序不工作

Question

我正在申请。我想从网络上的 Json 文件中获取一些信息。这行得通。现在我想要一个 onItemClickListener 到带有内容的 ListView 的项目。 onItemClickListener 必须将点击列表的信息发送到我的新 Activity 。

我的 MainActiviy.java 的代码是:

package com.jitesh.androidjsonparser;

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

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

import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;


public class MainActivity extends ListActivity {
    private Context context;
    private static String url = "http://docs.blackberry.com/sampledata.json"; // URL VAN HET JSON BESTAND

    private static final String TAG_VTYPE = "vehicleType"; //VELDEN UIT DE JSON HALEN
    private static final String TAG_VCOLOR = "vehicleColor";
    private static final String TAG_FUEL = "fuel";
    private static final String TAG_TREAD = "treadType";
    private static final String TAG_OPERATOR = "approvedOperators";
    private static final String TAG_NAME = "name";
    private static final String TAG_POINTS = "experiencePoints";

    ArrayList<HashMap<String, String>> jsonlist = new ArrayList<HashMap<String, String>>();

    ListView lv ;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        new ProgressTask(MainActivity.this).execute();
    }

    private class ProgressTask extends AsyncTask<String, Void, Boolean> {
        private ProgressDialog dialog;

        private ListActivity activity;

        // private List<Message> messages;
        public ProgressTask(ListActivity activity) {
            this.activity = activity;
            context = activity;
            dialog = new ProgressDialog(context);
        }

        /** progress dialog to show user that the backup is processing. */

        /** application context. */
        private Context context;

        protected void onPreExecute() {
            this.dialog.setMessage("Progress start");
            this.dialog.show();
        }

        @Override
        protected void onPostExecute(final Boolean success) {
            if (dialog.isShowing()) {
                dialog.dismiss();
            }
            ListAdapter adapter = new SimpleAdapter(context, jsonlist,
                    R.layout.list_item, new String[] { TAG_VTYPE, TAG_VCOLOR,
                            TAG_FUEL, TAG_TREAD }, new int[] {
                            R.id.vehicleType, R.id.vehicleColor, R.id.fuel,
                            R.id.treadType });

            setListAdapter(adapter);

            // selecting single ListView item
             lv = getListView();             
        }

        protected Boolean doInBackground(final String... args) {

            JSONParser jParser = new JSONParser();

            // getting JSON string from URL
            JSONArray json = jParser.getJSONFromUrl(url);

            for (int i = 0; i < json.length(); i++) {

                try {
                    JSONObject c = json.getJSONObject(i);
                    String vtype = c.getString(TAG_VTYPE);

                    String vcolor = c.getString(TAG_VCOLOR);
                    String vfuel = c.getString(TAG_FUEL);
                    String vtread = c.getString(TAG_TREAD);

                    HashMap<String, String> map = new HashMap<String, String>();

                    // adding each child node to HashMap key => value
                    map.put(TAG_VTYPE, vtype);
                    map.put(TAG_VCOLOR, vcolor);
                    map.put(TAG_FUEL, vfuel);
                    map.put(TAG_TREAD, vtread);
                    jsonlist.add(map);
                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            return null;

        }


    }

}

谁能帮我解决 onItemClickListener 以及我必须在哪个地方设置这个 onItemClickListener？

@Override protected void onListItemClick(ListView lv, View v, int position, long id) {       
         Intent i = new Intent(getApplicationContext(), single_list_item_view.class);     
         String vehicleType = ((TextView) v).getText().toString();   
         i.putExtra("TAG_VTYPE", vehicleType); 
         startActivity(i); 
 }

Answer 1

您正在扩展 ListActivity，因此您不需要 onItemClickListener。你可以直接覆盖onListItemClick(ListView l, View v, int position, long id)。选择列表中的项目时将调用此方法。

正如您对 onCreate 所做的那样，您可以对 onListItemClick

执行相同的操作

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    Intent i = new Intent(this, single_list_item_view.class);     
    HashMap<String, String> itemPressed = (HashMap<String, String>)l.getItemAtPosition(position); 
    String vehicleType = itemPressed.get(TAG_VTYPE);   
     i.putExtra("TAG_VTYPE", vehicleType); 
     startActivity(i); 
}