Php 当我点击单一列表时，它崩溃并给出空指针异常

我正在创建一个酒店目录。当我单击hotels的列表项时，它会显示列表，但当我单击single list时，它会崩溃，并在doinbackground方法的该文件中给出空指针异常

在这个文件中，我试图从数据库中获取每个酒店的数据。我在一个活动中输入酒店数据，该活动保存到数据库并以列表的形式显示。但我单击每个列表项，即酒店名称，它应该显示酒店的详细信息，如位置和电话号码等。下面是我的EditProductActivity.java代码：

import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

    public class EditProductActivity extends Activity {

            EditText txtName;
            EditText txtPhone;
            EditText txtMobile;
            EditText txtDesc;
      EditText txtCreatedAt;
       Button btnSave;
       Button btnDelete;

       String pid;

            // Progress Dialog
       private ProgressDialog pDialog;

            // JSON parser class
       JSONParser jsonParser = new JSONParser();

            // single product url
       private static final String url_product_detials = "http://10.0.2.2/android_hive/get_product_details1.php";

            // url to update product
     private static final String url_update_product = "http://10.0.2.2/android_hive/update_product1.php";

            // url to delete product
            private static final String url_delete_product = "http://10.0.2.2/android_hive/delete_product1.php";

            // JSON Node names
       private static final String TAG_SUCCESS = "success";
       private static final String TAG_PRODUCT = "product";
       private static final String TAG_PID = "pid";
       private static final String TAG_NAME = "name";
       private static final String TAG_PRICE = "phone";
            private static final String TAG_MOBILE = "mobile";
            private static final String TAG_DESCRIPTION = "location";

            @Override
       public void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.edit_product);

                // save button
        btnSave = (Button) findViewById(R.id.btnSave);
        btnDelete = (Button) findViewById(R.id.btnDelete);

                // getting product details from intent
                Intent i = getIntent();

                // getting product id (pid) from intent
        pid = i.getStringExtra(TAG_PID);

                // Getting complete product details in background thread
                new GetProductDetails().execute();

                // save button click event
                btnSave.setOnClickListener(new View.OnClickListener() {

                    @Override
                    public void onClick(View arg0) {
                        // starting background task to update product
                        new SaveProductDetails().execute();
                    }
                });

                // Delete button click event
                btnDelete.setOnClickListener(new View.OnClickListener() {

                    @Override
                    public void onClick(View arg0) {
                        // deleting product in background thread
                        new DeleteProduct().execute();
                    }
                });

            }

            /**
             * Background Async Task to Get complete product details
             * */
            class GetProductDetails extends AsyncTask<String, String, String> {

                /**
                 * Before starting background thread Show Progress Dialog
                 * */
                @Override
                protected void onPreExecute() {
                    super.onPreExecute();
                    pDialog = new ProgressDialog(EditProductActivity.this);
                    pDialog.setMessage("Loading hotel details. Please wait...");
                    pDialog.setIndeterminate(false);
                    pDialog.setCancelable(true);
                    pDialog.show();
                }

                /**
                 * Getting product details in background thread
                 * */
                protected String doInBackground(String... params) {

                    // updating UI from Background Thread
                    runOnUiThread(new Runnable() {
                        public void run() {
                            // Check for success tag
                            int success;
                            try {
                                // Building Parameters
                                List<NameValuePair> params = new ArrayList<NameValuePair>();
                                params.add(new BasicNameValuePair("pid", pid));

                                // getting product details by making HTTP request
                                // Note that product details url will use GET request
                                JSONObject json = jsonParser.makeHttpRequest(
                                        url_product_detials, "GET", params);

                                // check your log for json response
                                Log.d("Single Product Details", json.toString());

                                // json success tag
                                success = json.getInt(TAG_SUCCESS);
                                if (success == 1) {
                                    // successfully received product details
                                    JSONArray productObj = json
                                            .getJSONArray(TAG_PRODUCT); // JSON Array

                                    // get first product object from JSON Array
                                    JSONObject product = productObj.getJSONObject(0);

                                    // hotel with this pid found
                                    // Edit Text
                                    txtName = (EditText) findViewById(R.id.inputName);
                                    txtPhone = (EditText) findViewById(R.id.inputPrice);
                                    txtMobile = (EditText) findViewById(R.id.inputMobile);
                                    txtDesc = (EditText) findViewById(R.id.inputDesc);

                                    // display product data in EditText
                                    txtName.setText(product.getString(TAG_NAME));
                                    txtPhone.setText(product.getString(TAG_PRICE));
                                    txtMobile.setText(product.getString(TAG_MOBILE));
                                    txtDesc.setText(product.getString(TAG_DESCRIPTION));

                                }else{
                                    // product with pid not found
                                }
                            } catch (JSONException e) {
                                e.printStackTrace();
                            }
                        }
                    });

                    return null;
                }


                /**
                 * After completing background task Dismiss the progress dialog
                 * **/
                protected void onPostExecute(String file_url) {
                    // dismiss the dialog once got all details
                    pDialog.dismiss();
                }
            }

            /**
             * Background Async Task to  Save product Details
             * */
            class SaveProductDetails extends AsyncTask<String, String, String> {

                /**
                 * Before starting background thread Show Progress Dialog
                 * */
                @Override
                protected void onPreExecute() {
                    super.onPreExecute();
                    pDialog = new ProgressDialog(EditProductActivity.this);
                    pDialog.setMessage("Saving product ...");
                    pDialog.setIndeterminate(false);
                    pDialog.setCancelable(true);
                    pDialog.show();
                }

                /**
                 * Saving product
                 * */
                protected String doInBackground(String... args) {

                    // getting updated data from EditTexts
                    String name = txtName.getText().toString();
                    String phone = txtPhone.getText().toString();
                    String mobile = txtMobile.getText().toString();
                    String location = txtDesc.getText().toString();

                    // Building Parameters
                    List<NameValuePair> params = new ArrayList<NameValuePair>();
                    params.add(new BasicNameValuePair(TAG_PID, pid));
                    params.add(new BasicNameValuePair(TAG_NAME, name));
                    params.add(new BasicNameValuePair(TAG_PRICE, phone));
                    params.add(new BasicNameValuePair(TAG_MOBILE, mobile));
                    params.add(new BasicNameValuePair(TAG_DESCRIPTION, location));

                    // sending modified data through http request
                    // Notice that update product url accepts POST method
                    JSONObject json = jsonParser.makeHttpRequest(url_update_product,
                            "POST", params);

                    // check json success tag
                    try {
                        int success = json.getInt(TAG_SUCCESS);

                        if (success == 1) {
                            // successfully updated
                            Intent i = getIntent();
                            // send result code 100 to notify about product update
                            setResult(100, i);
                            finish();
                        } else {
                            // failed to update product
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }

                    return null;
                }


                /**
                 * After completing background task Dismiss the progress dialog
                 * **/
                protected void onPostExecute(String file_url) {
                    // dismiss the dialog once product uupdated
                    pDialog.dismiss();
                }
            }

            /*****************************************************************
             * Background Async Task to Delete Product
             * */
            class DeleteProduct extends AsyncTask<String, String, String> {

                /**
                 * Before starting background thread Show Progress Dialog
                 * */
                @Override
                protected void onPreExecute() {
                    super.onPreExecute();
                    pDialog = new ProgressDialog(EditProductActivity.this);
                    pDialog.setMessage("Deleting Product...");
                    pDialog.setIndeterminate(false);
                    pDialog.setCancelable(true);
                    pDialog.show();
                }

                /**
                 * Deleting product
                 * */
                protected String doInBackground(String... args) {

                    // Check for success tag
                    int success;
                    try {
                        // Building Parameters
                        List<NameValuePair> params = new ArrayList<NameValuePair>();
                        params.add(new BasicNameValuePair("pid", pid));

                        // getting product details by making HTTP request
                        JSONObject json = jsonParser.makeHttpRequest(
                                url_delete_product, "POST", params);

                        // check your log for json response
                        Log.d("Delete Product", json.toString());

                        // json success tag
                        success = json.getInt(TAG_SUCCESS);
                        if (success == 1) {
                            // product successfully deleted
                            // notify previous activity by sending code 100
                            Intent i = getIntent();
                            // send result code 100 to notify about product deletion
                            setResult(100, i);
                            finish();
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }

                    return null;
                }

                /**
                 * After completing background task Dismiss the progress dialog
                 * **/
                protected void onPostExecute(String file_url) {
                    // dismiss the dialog once product deleted
                    pDialog.dismiss();

                }

            }
        }

import java.util.ArrayList；
导入java.util.List；
导入org.apache.http.NameValuePair；
导入org.apache.http.message.BasicNameValuePair；
导入org.json.JSONArray；
导入org.json.JSONException；
导入org.json.JSONObject；
导入android.app.Activity；
导入android.app.ProgressDialog；
导入android.content.Intent；
导入android.os.AsyncTask；
导入android.os.Bundle；
导入android.util.Log；
导入android.view.view；
导入android.widget.Button；
导入android.widget.EditText；
公共类EditProductActivity扩展了活动{
编辑文本txtName；
编辑文本txtPhone；
EditText-txtMobile；
编辑文本txtDesc；
编辑文本txtCreatedAt；
按钮btnSave；
按钮btnDelete；
串pid；
//进度对话框
私人对话；
//JSON解析器类
JSONParser JSONParser=新的JSONParser（）；
//单一产品url
私有静态最终字符串url\u product\u detials=”http://10.0.2.2/android_hive/get_product_details1.php";
//更新产品的url
私有静态最终字符串url\u更新\u产品=”http://10.0.2.2/android_hive/update_product1.php";
//用于删除产品的url
私有静态最终字符串url\u delete\u product=”http://10.0.2.2/android_hive/delete_product1.php";
//JSON节点名称
私有静态最终字符串标记_SUCCESS=“SUCCESS”；
私有静态最终字符串TAG_PRODUCT=“PRODUCT”；
私有静态最终字符串标记_PID=“PID”；
私有静态最终字符串标记_NAME=“NAME”；
私有静态最终字符串标记_PRICE=“phone”；
私有静态最终字符串标记_MOBILE=“MOBILE”；
私有静态最终字符串标记\u DESCRIPTION=“location”；
@凌驾
创建时的公共void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.edit_产品）；
//保存按钮
btnSave=（按钮）findviewbyd（R.id.btnSave）；
btnDelete=（按钮）findViewById（R.id.btnDelete）；
//从intent获取产品详细信息
Intent i=getIntent（）；
//从intent获取产品id（pid）
pid=i.getStringExtra（标签\ pid）；
//在后台线程中获取完整的产品详细信息
新建GetProductDetails（）.execute（）；
//保存按钮单击事件
btnSave.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图arg0）{
//正在启动后台任务以更新产品
新建SaveProductDetails（）.execute（）；
}
});
//删除按钮单击事件
btnDelete.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图arg0）{
//删除后台线程中的产品
新的DeleteProduct（）.execute（）；
}
});
}
/**
*获取完整产品详细信息的后台异步任务
* */
类GetProductDetails扩展了AsyncTask{
/**
*在启动后台线程显示进度对话框之前
* */
@凌驾
受保护的void onPreExecute（）{
super.onPreExecute（）；
pDialog=newprogressdialog（EditProductActivity.this）；
pDialog.setMessage（“正在加载酒店详细信息，请稍候…”）；
pDialog.setUndeterminate（假）；
pDialog.setCancelable（真）；
pDialog.show（）；
}
/**
*在后台线程中获取产品详细信息
* */
受保护的字符串doInBackground（字符串…参数）{
//从后台线程更新UI
runOnUiThread（新的Runnable（）{
公开募捐{
//检查成功标签
成功；
试一试{
//建筑参数
List params=new ArrayList（）；
参数添加（新的BasicNameValuePair（“pid”，pid））；
//通过发出HTTP请求获取产品详细信息
//请注意，产品详细信息url将使用GET请求
JSONObject json=jsonParser.makeHttpRequest(
url（产品详细信息，“获取”，参数）；
//检查日志中的json响应
Log.d（“单一产品详细信息”，json.toString（））；
//json成功标记
success=json.getInt（TAG_success）；
如果（成功==1）{
//已成功接收产品详细信息
JSONArray productObj=json
        <?php

        /*
         * Following code will get single product details
         * A product is identified by product id (pid)
         */

        // array for JSON response
        $response = array();

        // include db connect class
        require_once __DIR__ . '/db_connect1.php';

        // connecting to db
        $db = new DB_CONNECT();

        // check for post data
        if (isset($_GET["pid"])) {
            $pid = $_GET['pid'];

            // get a product from products table
            $result = mysql_query("SELECT *FROM info WHERE pid = $pid");

            if (!empty($result)) {
                // check for empty result
                if (mysql_num_rows($result) > 0) {

                    $result = mysql_fetch_array($result);

                    $product = array();
                    $product["pid"] = $result["pid"];
                    $product["name"] = $result["name"];
                    $product["phone"] = $result["phone"];
                    $product["mobile"] = $result["mobile"];
                    $product["location"] = $result["location"];
                    $product["created_at"] = $result["created_at"];
                    $product["updated_at"] = $result["updated_at"];
                    // success
                    $response["success"] = 1;

                    // user node
                    $response["product"] = array();

                    array_push($response["product"], $product);

                    // echoing JSON response
                    echo json_encode($response);
                } else {
                    // no product found
                    $response["success"] = 0;
                    $response["message"] = "No product found";

                    // echo no users JSON
                    echo json_encode($response);
                }
            } else {
                // no product found
                $response["success"] = 0;
                $response["message"] = "No product found";

                // echo no users JSON
                echo json_encode($response);
            }
        } else {
            // required field is missing
            $response["success"] = 0;
            $response["message"] = "Required field(s) is missing";

            // echoing JSON response
            echo json_encode($response);
        }
        ?>

txtName = (EditText) findViewById(R.id.inputName);
txtPhone = (EditText) findViewById(R.id.inputPrice);
txtMobile = (EditText) findViewById(R.id.inputMobile);
txtDesc = (EditText) findViewById(R.id.inputDesc);

 // display product data in EditText
 txtName.setText(product.getString(TAG_NAME));
 txtPhone.setText(product.getString(TAG_PRICE));
 txtMobile.setText(product.getString(TAG_MOBILE));
 txtDesc.setText(product.getString(TAG_DESCRIPTION));

   protected void onPostExecute(String file_url) {
                // dismiss the dialog once got all details
                 pDialog.dismiss();
   txtName = (EditText) findViewById(R.id.inputName);
   txtPhone = (EditText) findViewById(R.id.inputPrice);
   txtMobile = (EditText) findViewById(R.id.inputMobile);
  txtDesc = (EditText) findViewById(R.id.inputDesc);

   // display product data in EditText
   txtName.setText(product.getString(TAG_NAME));
   txtPhone.setText(product.getString(TAG_PRICE));
   txtMobile.setText(product.getString(TAG_MOBILE));
   txtDesc.setText(product.getString(TAG_DESCRIPTION));
}