我这里有我的java代码。
package com.atthesis.ticmip;
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.os.AsyncTask;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
public class Mainusersdictionary extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> dilist;
// url to get all products list
private static String url_all_dictionary = "http://10.0.2.2/android/get_dictionary.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_dictionary = "disease";
private static final String TAG_RID = "rid";
private static final String TAG_NAME = "disease";
// products JSONArray
JSONArray diseases = null;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_usersdictionary);
setTitle("Mga Sakit");
StrictMode.enableDefaults();
// Hashmap for ListView
dilist = new ArrayList<HashMap<String, String>>();
// Loading products in Background Thread
new LoadAlldisease().execute();
// Get listview
//ListView lv = getListView();
ListView lv =(ListView)findViewById(android.R.id.list);
}
/**
* Background Async Task to Load all product by making HTTP Request
* */
class LoadAlldisease extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(Mainusersdictionary.this);
pDialog.setMessage("Loading diseases. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* 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_dictionary, "GET", params);
// Check your log cat for JSON reponse
Log.d("Diseases: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
diseases = json.getJSONArray(TAG_dictionary);
// looping through All Products
for (int i = 0; i < diseases.length(); i++) {
JSONObject c = diseases.getJSONObject(i);
// Storing each json item in variable
String rid = c.getString(TAG_RID);
String reg = c.getString(TAG_NAME);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_RID, rid);
map.put(TAG_NAME, reg);
// adding HashList to ArrayList
dilist.add(map);
}
} else {
// no products found
// Launch Add New product Activity
/*Intent i = new Intent(getApplicationContext(),
NewProductActivity.class);
// Closing all previous activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);*/
Toast.makeText(getApplicationContext(), "No Region", Toast.LENGTH_LONG).show();
}
} 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
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
Mainusersdictionary.this, dilist,
R.layout.ctxtview, new String[] { TAG_RID,
TAG_NAME},
new int[] { R.id.rid, R.id.name });
// updating listview
ListView lv =(ListView)findViewById(android.R.id.list);
lv.setAdapter(adapter);
//setListAdapter(adapter);
}
});
}
}
}
和一个php文件，它可以从mysql中检索数据
<?php
/*
* Following code will list all the products
*/
// array for JSON response
$response = array();
// include db connect class
require_once __DIR__ . '/db_connect.php';
// connecting to db
$db = new DB_CONNECT();
// get all products from products table
$result = mysql_query("SELECT rid, disease FROM ddictionary") or die(mysql_error());
// check for empty result
if (mysql_num_rows($result) > 0) {
// looping through all results
// products node
$response["diseases"] = array();
while ($row = mysql_fetch_array($result)) {
// temp user array
$diseases = array();
$diseases["rid"] = $row["rid"];
$diseases["disease"] = $row["disease"];
// push single product into final response array
array_push($response["diseases"], $regions);
}
// success
$response["success"] = 1;
// echoing JSON response
echo json_encode($response);
} else {
// no products found
$response["success"] = 0;
$response["message"] = "No products found";
// echo no users JSON
echo json_encode($response);
}
?>
我收到错误
01-28 20:48:26.517: E/JSON Parser(5033): Error parsing data org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONObject
01-28 20:48:26.582: I/Choreographer(5033): Skipped 427 frames! The application may be doing too much work on its main thread.
01-28 20:48:26.991: I/Choreographer(5033): Skipped 104 frames! The application may be doing too much work on its main thread.
01-28 20:48:27.096: E/AndroidRuntime(5033): FATAL EXCEPTION: AsyncTask #1
01-28 20:48:27.096: E/AndroidRuntime(5033): Process: com.atthesis.ticmip, PID: 5033
01-28 20:48:27.096: E/AndroidRuntime(5033): java.lang.RuntimeException: An error occured while executing doInBackground()
01-28 20:48:27.096: E/AndroidRuntime(5033): at android.os.AsyncTask$3.done(AsyncTask.java:300)
01-28 20:48:27.096: E/AndroidRuntime(5033): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
01-28 20:48:27.096: E/AndroidRuntime(5033): at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
01-28 20:48:27.096: E/AndroidRuntime(5033): at java.util.concurrent.FutureTask.run(FutureTask.java:242)
01-28 20:48:27.096: E/AndroidRuntime(5033): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
01-28 20:48:27.096: E/AndroidRuntime(5033): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
01-28 20:48:27.096: E/AndroidRuntime(5033): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
01-28 20:48:27.096: E/AndroidRuntime(5033): at java.lang.Thread.run(Thread.java:818)
01-28 20:48:27.096: E/AndroidRuntime(5033): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String org.json.JSONObject.toString()' on a null object reference
01-28 20:48:27.096: E/AndroidRuntime(5033): at com.atthesis.ticmip.Mainusersdictionary$LoadAlldisease.doInBackground(Mainusersdictionary.java:97)
01-28 20:48:27.096: E/AndroidRuntime(5033): at com.atthesis.ticmip.Mainusersdictionary$LoadAlldisease.doInBackground(Mainusersdictionary.java:1)
01-28 20:48:27.096: E/AndroidRuntime(5033): at android.os.AsyncTask$2.call(AsyncTask.java:288)
01-28 20:48:27.096: E/AndroidRuntime(5033): at java.util.concurrent.FutureTask.run(FutureTask.java:237)
01-28 20:48:27.096: E/AndroidRuntime(5033): ... 4 more
此错误导致我的应用停止。那么解决这个问题的解决方案或方法是什么呢？我在这里做了所有谷歌的东西，但没有影响我的应用程序。请帮我解决这个或者更好的代码在这里？先谢谢先生
答案 0 :(得分：0)
您能否发布服务器电话的输出？ IE浏览器。打开这个网址：
在浏览器中看看你得到了什么。
消息
"Value <br of type java.lang.String"
建议应用程序收到的响应的起始字符是HTML代码而不是JSON数组。可能是服务器端的一些错误/警告/通知输出。
编辑1
我只是想看看实际的服务器响应，看看你的服务器是否返回了有效的JSON对象。我看到的方式是JSONParser类中的某个地方（我假设它是你自己编写的一个类）你用数据创建一个JSONObject，这些数据不是真正的JSON数据，或者至少不被认为是这样的
我会探索两个选项：
创建一个静态.json文件，其中包含您确定正确的内容，并在应用程序中使用该内容而不是PHP文件输出。如果工作正常，您就知道问题出在服务器上，而不是应用程序中。
从您发布的php文件中，如果您已将服务器的输出标头设置为app / json，则不清楚。虽然它不是强制性的，但我建议您始终指定生成的输出标题，例如：
标题（＆＃39;内容类型：application / json＆＃39;）;
将它放在echo json_encode（...）行的前面。 （但是，在发送标头之前，您不能从服务器获得任何其他输出（回显或错误消息），否则您将收到错误消息。）
我建议你尝试这两个选项，让我们知道发生了什么/改变了什么。
答案 1 :(得分：0)
我认为之前我遇到过同样的问题，检查你的.php输出。 我注意到JSON相似的解析器读取输出代码的每个部分，包括html注释。 如果您可以使用另一个HttpClient（可能是Apache）并检查Toast.makeText（）中的输出或类似的东西。 也尝试使用 出口（json_encode（$响应））;