5

我正在尝试为我的最后一年项目开发一个 android 应用程序，我正处于需要将数据库连接到我的应用程序的地步。我之前已经连接到内部和外部 SQLite 数据库，但我的主管说我必须使用 XAMPP localhost，所以稍后它是合理的，因为它与使用 Web 服务器的现实情况非常相似。这是我的 DBHelper 类的代码，我改编自我在网上找到的示例代码并确实改变了一些东西，但我很确定有很多错误。当按下会导致该类的查看数据的按钮时，它只会显示一个空白屏幕，并且在很长一段时间后会崩溃。

package com.example.parking_guide;

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

import org.apache.http.NameValuePair;
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.database.Cursor;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
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 DBHelper extends ListActivity {


    // Progress Dialog
    private ProgressDialog pDialog;

    // Creating JSON Parser object
    JSONParser jParser = new JSONParser();

    ArrayList<HashMap<String, String>> productsList;

    // url to get all products list
    private static final String url_all_products = "http://10.0.0.2/android_connect/get_all_products.php";

    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCTS = "products";
    private static final String KEY_ROWID = "_id";
    private static final String KEY_VACANT = "vacancy";

    // products JSONArray
    JSONArray table = null;  

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ListView yourListView = getListView();



        // Hashmap for ListView
        productsList = new ArrayList<HashMap<String, String>>();

        // Loading products in Background Thread
        new LoadAllProducts().execute();

    }
    /**
     * Background Async Task to Load all product by making HTTP Request
     * */
    class LoadAllProducts extends AsyncTask<String, String, String> {


        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override

        /**
         * getting All products from url
         * */
        protected String doInBackground(String... args) {
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            // getting JSON string from URL
            JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);

            // Check your log cat for JSON reponse
            Log.d("Level1: ", json.toString());

            try {
                // Checking for SUCCESS TAG
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // products found
                    // Getting Array of Products
                    table = json.getJSONArray(TAG_PRODUCTS);

                    // looping through All Products
                    for (int i = 0; i < table.length(); i++) {
                        JSONObject c = table.getJSONObject(i);

                        // Storing each json item in variable
                        String _id = c.getString(KEY_ROWID);
                        String vacant = c.getString(KEY_VACANT);

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


                        // adding each child node to HashMap key => value
                        map.put(KEY_ROWID, _id);
                        map.put(KEY_VACANT, vacant);

                        // adding HashList to ArrayList
                        productsList.add(map);
                    }
                } 
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return null;

        }


        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after getting all products
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */
                    ListAdapter adapter = new SimpleAdapter(
                            DBHelper.this, productsList,
                            R.layout.list_item, new String[] { KEY_ROWID,
                                    KEY_VACANT},
                            new int[] { R.id.id, R.id.vac});
                    // updating listview
                    setListAdapter(adapter);
                }
            });

        }


    }
}

所以我真的不知道出了什么问题，因为我不太擅长 android，只是在继续学习。谁能帮助我？

4

1 回答 1

3

您应该使用 10.0.2.2 来访问您的本地主机，而不是 10.0.0.2 :) http://developer.android.com/tools/devices/emulator.html#networkaddresses

于 2013-06-22T08:29:23.690 回答