所以当我运行它时，我的Android应用程序出现2个错误。 first- / Buffer Error：转换结果时出错java.lang.NullPointerException：lock == null second- / JSON Parser：解析数据时出错org.json.JSONException：字符0处的输入结束...似乎我已经阅读了与同一问题有关的无数问题，但没有一个对我的情况有所帮助。我将用户名从共享首选项传递给我的php，所以我可以从DB查询当前用户。我从网上运行了PHP，一切似乎都在上升。希望有人可以帮助发现我的错误......继承人的代码 All_Content.java
package com.example.mrbuknahsty.annovoteexdb;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.SimpleAdapter;
import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
/**
* Created by mr.buknahsty on 5/10/2016.
*/
public class All_Content extends ListActivity
{
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> contentList;
sessionManager session;
// url to get all products list
private static String url_all_content =
"http://www.lkirkpatrick.btcwsd.com/anno/all.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_CONTENT = "content";
private static final String TAG_T_ID = "t_id";
private static final String TAG_NAME = "name";
// products JSONArray
JSONArray contents = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_content);
// Hashmap for ListView
contentList = 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
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(All_Content.this);
pDialog.setMessage("Loading products. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products from url
* */
protected String doInBackground(String... args) {
session = new sessionManager(getApplicationContext());
session.checkLogin();
HashMap<String, String> user = session.getUserDetails();
// name
String uName = user.get(sessionManager.KEY_NAME);
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>
(1);
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_content,
uName+"GET", params);
if(json!=null) {
// do something
Log.d("results: ", json.toString());
// Check your log cat for JSON reponse
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
contents = json.getJSONArray(TAG_CONTENT);
// looping through All Products
for (int i = 0; i < contents.length(); i++)
{
JSONObject c = contents.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_T_ID);
String name = 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_T_ID, id);
map.put(TAG_NAME, name);
// adding HashList to ArrayList
contentList.add(map);
}
} else {
// no products found
// Launch Add New product Activity
Intent i = new Intent(getApplicationContext(),
All_Content.class);
// Closing all previous activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
} 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(
All_Content.this, contentList,
R.layout.list_item, new String[] { TAG_T_ID,
TAG_NAME},
new int[] { R.id.t_id, R.id.name });
// updating listview
setListAdapter(adapter);
}
});
}
}
}
JSONParser类
package com.example.mrbuknahsty.annovoteexdb;
import android.util.Log;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
/**
* Created by mr.buknahsty on 5/10/2016.
*/
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET mehtod
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
}catch(Exception e)
{
Log.i("Buffer Error", "Error converting result " +
e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.i("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
all.php
<?php
require_once 'get_all.php';
$uName = "";
if(isset($_POST['uName']))
{
$uName = $_POST['uName'];
}
// Instance of a Topic class
$get_AllObject = new get_All();
// Registration of new topic
if(!empty($uName))
{
$json_registration = $get_AllObject->getAll($uName);
echo json_encode($json_registration);
}
?>
和我的get_all.php
<?php
include_once 'error.php';
class get_All{
private $db;
private $db_table = "topics";
public function __construct()
{
$this->db = new DbConnect();
}
public function getAll($uName)
{
$response = array();
///////////////////////////////////////////
//USERS TABLE
//query to get current logged in user_id
$un = "SELECT * FROM users WHERE username = '$uName'";
//running query
$unResults = mysqli_query($this->db->getDb(), $un);
//get user_id results from query **CREDIT GOES TO BEN LAPAZ FOR THIS..
while ($row = mysqli_fetch_array($unResults))
{
$id = ($row['user_id']);
}
//now i have current user_id
/////////////////////////////////////////////////////////
//CREATED_TOPICS TABLE
//query to get all data from created_topics thats under user_id that
matches current user_id
$t_id = "SELECT * FROM created_topics WHERE user_id = '$id'";
//running query
$t_id_Results = mysqli_query($this->db->getDb(), $t_id);
//get topic_id results from query
while ($rowT = mysqli_fetch_array($t_id_Results))
{
$id_T = ($rowT['topic_id']);
}
//now i have all topic_ids' for current user
/////////////////////////////////////////////////////////////////////////
//TOPICS TABLE
//query to get all data from topics thats has to do with topic_ids from
previous query
$userContent = "SELECT * FROM topics WHERE topic_id = '$id_T'";
$userContentResults = mysqli_query($this->db->getDb(),$userContent);
//running query
if ($userContentResults && mysqli_num_rows($userContentResults) > 0)
{
// looping through all results
// products node
$response["content"] = array();
//get content results from query
while ($rowContent = mysqli_fetch_array($userContent))
{
$content = array();
$content["topic_id"] = $row["topic_id"];
$content["topic_name"] = $row["topic_name"];
$content["content"] = $row["content"];
$content["code"] = $row["code"];
$content["created_at"] = $row["created_at"];
$content["updated_at"] = $row["updated_at"];
// push single content into final response array
array_push($response["content"], $content);
}
// 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);
}
}
}
?>
并记录///这是我得到的全部
05-12 08:34:41.728 12650-12740/com.example.mrbuknahsty.annovoteexdb
I/Buffer Error: Error converting result java.lang.NullPointerException: lock
== null
05-12 08:34:41.728 12650-12740/com.example.mrbuknahsty.annovoteexdb
I/JSON Parser: Error parsing data org.json.JSONException: End of input at
character 0 of
05-12 08:34:41.828 12650-12650/com.example.mrbuknahsty.annovoteexdb
I/Timeline:
Timeline: Activity_idle id: android.os.BinderProxy@41b644f8 time:47813028