我设法解决除JSONException错误之外的所有问题。我知道我的代码效率不高，可以通过使用asynctask等进行改进，但现在解决这个错误是我的优先级列表，所以请帮我解决这个问题。
我正在分享所有必需的代码和详细信息。
MSRITShowAttendance.java：
package com.vasan.msritstudentservice;
import java.util.ArrayList;
import java.util.HashMap;
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.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MSRITShowAttendance extends Activity
{
JSONParser JP = new JSONParser();
ProgressDialog PDial = null;
String Pswd, stpwd;
Button Attendance;
EditText AIDEdit, SPEdit;
TextView StIDView, SuIDView, TCView, CAView, PView, CView;
private static String url_att_view = "http://10.0.2.2/MSRIT_Student_Info_Handles/MSRIT_retrieve_particular_attendance.php";
private static final String TAG_ATTENDANCE_SUCCESS = "success";
private static final String TAG_ATTENDANCE_ARRAY = "attendance";
private static final String TAG_ATTENDANCE_STUDID = "studid";
private static final String TAG_ATTENDANCE_SUBID = "subid";
private static final String TAG_ATTENDANCE_TOTALCLASSES = "totalclasses";
private static final String TAG_ATTENDANCE_ATTENDEDCLASSES = "attendedclasses";
private static final String TAG_ATTENDANCE_PERCENTAGE = "percentage";
private static final String TAG_ATTENDANCE_COMMENTS = "comments";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.msrit_student_details);
Attendance = (Button) findViewById(R.id.ViewAttendance);
AIDEdit = (EditText) findViewById(R.id.AttIDEdit);
SPEdit = (EditText) findViewById(R.id.PasswordEdit);
StIDView = (TextView) findViewById(R.id.StudentIDView);
SuIDView = (TextView) findViewById(R.id.SubjectIDView);
TCView = (TextView) findViewById(R.id.TotalClassesView);
CAView = (TextView) findViewById(R.id.ClassesAttendedView);
PView = (TextView) findViewById(R.id.PercentageView);
CView = (TextView) findViewById(R.id.CommentView);
Attendance.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
PDial = ProgressDialog.show(MSRITShowAttendance.this, "", "Validating user.Please wait...", true);
new Thread(new Runnable()
{
public void run()
{
showDetails();
}
}).start();
}
});
}
void showDetails()
{
try
{
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("attid",AIDEdit.getText().toString().trim()));
params.add(new BasicNameValuePair("studpwd",SPEdit.getText().toString().trim()));
JSONObject json = JP.makeHttpRequest(url_att_view, "GET", params);
int success = json.getInt(TAG_ATTENDANCE_SUCCESS);
new Thread(new Runnable(){
public void run()
{
PDial.dismiss();
}
}).start();
if (success == 1)
{
runOnUiThread(new Runnable()
{
public void run()
{
Toast.makeText(getApplicationContext(),"Login Credentials Verified!!", Toast.LENGTH_SHORT).show();
}
});
JSONArray attendance = json.getJSONArray(TAG_ATTENDANCE_ARRAY);
JSONObject c = attendance.getJSONObject(0);
String TC = ""+(c.getInt(TAG_ATTENDANCE_TOTALCLASSES));
String AC = ""+(c.getInt(TAG_ATTENDANCE_ATTENDEDCLASSES));
String PCNTG = ""+(c.getInt(TAG_ATTENDANCE_PERCENTAGE));
String CMTS = ""+(c.getInt(TAG_ATTENDANCE_COMMENTS));
StIDView.setText(("Student ID: "+c.getString(TAG_ATTENDANCE_STUDID)));
SuIDView.setText(("Subject ID: "+c.getString(TAG_ATTENDANCE_SUBID)));
TCView.setText(("Total Classes: "+TC.trim()));
CAView.setText(("Classes Attended: "+AC.trim()));
PView.setText(("Percentage: "+PCNTG.trim()));
CView.setText(("Comments: "+CMTS.trim()));
}
else
{
showAlert();
}
}
catch(JSONException E)
{
PDial.dismiss();
E.printStackTrace();
}
}
void showAlert()
{
MSRITShowAttendance.this.runOnUiThread(new Runnable()
{
public void run()
{
AlertDialog.Builder builder = new AlertDialog.Builder(MSRITShowAttendance.this);
builder.setTitle("Database Error:Record not found.");
builder.setMessage("To User:Please check if you have registered.")
.setCancelable(false)
.setPositiveButton("OK", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int id)
{
}
});
AlertDialog alert = builder.create();
alert.show();
}
});
}
}
JSONParser.java：
package com.vasan.msritstudentservice;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
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 android.util.Log;
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.equals("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.equals("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();
Log.e("The Resultant String is",json);
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser results",json);
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
MSRIT_Retrieve_Particular_Attendance.php：
<?php
$response = array();
include 'MSRIT_db_connect.php';
$db = new DB_CONNECT();
if (isset($_GET["attid"]) && $_GET["studpwd"])
{
$attid = $_GET['attid'];
$studpwd = $_GET['studpwd'];
$result = mysql_query("SELECT * FROM attendance, studentdetails WHERE attid = '$attid' AND studpwd = '$studpwd' AND attendance.studid = studentdetails.studid");
if (!empty($result))
{
if (mysql_num_rows($result) > 0)
{
$result = mysql_fetch_array($result);
$attendance = array();
$attendance["attid"] = $result["attid"];
$attendance["studid"] = $result["studid"];
$attendance["subid"] = $result["subid"];
$attendance["totalclasses"] = $result["totalclasses"];
$attendance["attendedclasses"] = $result["attendedclasses"];
$attendance["percentage"] = $result["percentage"];
$attendance["comments"] = $result["comments"];
$response["success"] = 1;
$response["attendance"] = array();
array_push($response["attendance"], $attendance);
echo json_encode($response);
}
else
{
$response["success"] = 0;
$response["message"] = "No attendance found";
echo json_encode($response);
}
}
else
{
$response["success"] = 0;
$response["message"] = "No attendance found";
echo json_encode($response);
}
}
else
{
$response["success"] = 0;
$response["message"] = "Required field(s) is missing";
echo json_encode($response);
}
?>
logcat的：
03-27 08:18:36.672: E/The Resultant String is(776): <br />
03-27 08:18:36.672: E/The Resultant String is(776): <font size='1'><table class='xdebug-error xe-notice' dir='ltr' border='1' cellspacing='0' cellpadding='1'>
03-27 08:18:36.672: E/The Resultant String is(776): <tr><th align='left' bgcolor='#f57900' colspan="5"><span style='background-color: #cc0000; color: #fce94f; font-size: x-large;'>( ! )</span> Notice: Undefined index: comments in C:\wamp\www\MSRIT_Student_Info_Handles\MSRIT_retrieve_particular_attendance.php on line <i>22</i></th></tr>
03-27 08:18:36.672: E/The Resultant String is(776): <tr><th align='left' bgcolor='#e9b96e' colspan='5'>Call Stack</th></tr>
03-27 08:18:36.672: E/The Resultant String is(776): <tr><th align='center' bgcolor='#eeeeec'>#</th><th align='left' bgcolor='#eeeeec'>Time</th><th align='left' bgcolor='#eeeeec'>Memory</th><th align='left' bgcolor='#eeeeec'>Function</th><th align='left' bgcolor='#eeeeec'>Location</th></tr>
03-27 08:18:36.672: E/The Resultant String is(776): <tr><td bgcolor='#eeeeec' align='center'>1</td><td bgcolor='#eeeeec' align='center'>0.0005</td><td bgcolor='#eeeeec' align='right'>686336</td><td bgcolor='#eeeeec'>{main}( )</td><td title='C:\wamp\www\MSRIT_Student_Info_Handles\MSRIT_retrieve_particular_attendance.php' bgcolor='#eeeeec'>..\MSRIT_retrieve_particular_attendance.php<b>:</b>0</td></tr>
03-27 08:18:36.672: E/The Resultant String is(776): </table></font>
03-27 08:18:36.672: E/The Resultant String is(776): {"success":1,"attendance":[{"attid":"2","studid":"1MS10IS049","subid":"1","totalclasses":"44","attendedclasses":"0","percentage":"0.00","comments":null}]}
03-27 08:18:36.732: E/JSON Parser results(776): <br />
03-27 08:18:36.732: E/JSON Parser results(776): <font size='1'><table class='xdebug-error xe-notice' dir='ltr' border='1' cellspacing='0' cellpadding='1'>
03-27 08:18:36.732: E/JSON Parser results(776): <tr><th align='left' bgcolor='#f57900' colspan="5"><span style='background-color: #cc0000; color: #fce94f; font-size: x-large;'>( ! )</span> Notice: Undefined index: comments in C:\wamp\www\MSRIT_Student_Info_Handles\MSRIT_retrieve_particular_attendance.php on line <i>22</i></th></tr>
03-27 08:18:36.732: E/JSON Parser results(776): <tr><th align='left' bgcolor='#e9b96e' colspan='5'>Call Stack</th></tr>
03-27 08:18:36.732: E/JSON Parser results(776): <tr><th align='center' bgcolor='#eeeeec'>#</th><th align='left' bgcolor='#eeeeec'>Time</th><th align='left' bgcolor='#eeeeec'>Memory</th><th align='left' bgcolor='#eeeeec'>Function</th><th align='left' bgcolor='#eeeeec'>Location</th></tr>
03-27 08:18:36.732: E/JSON Parser results(776): <tr><td bgcolor='#eeeeec' align='center'>1</td><td bgcolor='#eeeeec' align='center'>0.0005</td><td bgcolor='#eeeeec' align='right'>686336</td><td bgcolor='#eeeeec'>{main}( )</td><td title='C:\wamp\www\MSRIT_Student_Info_Handles\MSRIT_retrieve_particular_attendance.php' bgcolor='#eeeeec'>..\MSRIT_retrieve_particular_attendance.php<b>:</b>0</td></tr>
03-27 08:18:36.732: E/JSON Parser results(776): </table></font>
03-27 08:18:36.732: E/JSON Parser results(776): {"success":1,"attendance":[{"attid":"2","studid":"1MS10IS049","subid":"1","totalclasses":"44","attendedclasses":"0","percentage":"0.00","comments":null}]}
03-27 08:18:36.732: E/JSON Parser(776): Error parsing data org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONObject
03-27 08:18:36.742: W/System.err(776): org.json.JSONException: No value for attendance
03-27 08:18:36.752: W/System.err(776): at org.json.JSONObject.get(JSONObject.java:354)
03-27 08:18:36.752: W/System.err(776): at org.json.JSONObject.getJSONArray(JSONObject.java:544)
03-27 08:18:36.762: W/System.err(776): at com.vasan.msritstudentservice.MSRITShowAttendance.showDetails(MSRITShowAttendance.java:104)
03-27 08:18:36.852: W/System.err(776): at com.vasan.msritstudentservice.MSRITShowAttendance$1$1.run(MSRITShowAttendance.java:72)
03-27 08:18:36.852: W/System.err(776): at java.lang.Thread.run(Thread.java:856)
答案 0 :(得分：0)
问题是你的＆＃34; JSON＆＃34; -String，正如它在Logcat中所说的那样。
您的＆＃34; json＆＃34; -string包含HTML-Tags，例如 br 或 font size =＆＃39; 1＆＃39; 等< / p>
只有Logcat中String-Result的最后一行是有效的JSON。但是你试图解析整个字符串，而不仅仅是JSON。
<强> //修改
发生此错误 - 如 D_Vaibhavツ告诉 - 因为您的Web服务器首先返回错误：
注意：未定义的索引：第22行的C：\ wamp \ www \ MSRIT_Student_Info_Handles \ MSRIT_retrieve_particular_attendance.php中的注释
答案 1 :(得分：0)
当您的Web服务没有返回有效的JSON时，会发生JSON解析错误。在这种情况下，您的服务器返回HTML内容和JSON。所以你在网络服务方面有问题。
查看您的PHP代码
您在MSRIT_retrieve_particular_attendance.php
注意：
中的Undefined index: comments
第22行C：\ wamp \ www \ MSRIT_Student_Info_Handles \ MSRIT_retrieve_particular_attendance.php
//this is Line 22. you are not getting anything named result["comments"]; from your database query Result I think
$attendance["comments"] = $result["comments"];
您的结果未返回名为＆＃34;评论＆＃34;
的列您可以签入该PHP代码，我建议您关闭PHP方面的警告，因为它可能不会影响您的最终结果
Here is the link会帮助你做到这一点