我目前正在开发Android应用程序，每当按下“登录”按钮时我都会收到错误消息。我知道有很多这种错误的例子，但我找不到一个与我相同的结构。这是我的代码：
LoginActivity.java：
package com.example.sabre8;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import com.example.sabre8.library.DatabaseHandler;
import com.example.sabre8.library.UserFunctions;
public class LoginActivity extends Activity {
Button btnLogin;
//Button btnLinkToRegister;
EditText inputUserID;
EditText inputPassword;
TextView loginErrorMsg;
// JSON Response node names
private static String KEY_SUCCESS = "success";
//private static String KEY_ERROR = "error";
//private static String KEY_ERROR_MSG = "error_msg";
private static String KEY_UserID = "UserID";
private static String KEY_PASSWORD = "Password";
private static String KEY_FNAME = "Fname";
private static String KEY_MNAME = "Mname";
private static String KEY_LNAME = "Lname";
private static String KEY_POSITION= "position";
private static String KEY_DEPARTMENT = "department";
// private static String KEY_NAME = "Fname";
private static String KEY_ADMINTYPE = "admintype";
private static String KEY_EMAIL = "email";
private static String KEY_VERIFIER = "verifier";
// private static String KEY_EMAIL = "email";
// private static String KEY_CREATED_AT = "created_at";
private class MyAsyncTask extends AsyncTask<String, Void, JSONObject> {
protected JSONObject doInBackground(String... params) {
UserFunctions userFunction = new UserFunctions();
if (params.length != 2)
return null;
JSONObject json = userFunction.loginUser(params[0], params[1]);
return json;
}
protected void onPostExecute(JSONObject json) {
try {
if (json != null && json.getString(KEY_SUCCESS) != null) {
loginErrorMsg.setText("");
String res = json.getString(KEY_SUCCESS);
if(Integer.parseInt(res) == 1){
// user successfully logged in
// Store user details in SQLite Database
DatabaseHandler db = new DatabaseHandler(getApplicationContext());
JSONObject json_user = json.getJSONObject("userID");
// Clear all previous data in database
UserFunctions userFunction = new UserFunctions();
userFunction.logoutUser(getApplicationContext());
//db.addUser(json_user.getString(KEY_NAME), json_user.getString(KEY_EMAIL), json.getString(KEY_UID), json_user.getString(KEY_CREATED_AT));
// Launch Main Screen
Intent main = new Intent(getApplicationContext(), MainActivity.class);
// Close all views before launching Dashboard
main.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(main);
// Close Login Screen
finish();
}else{
// Error in login
loginErrorMsg.setText("Incorrect username/password");
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
// Importing all assets like buttons, text fields
inputUserID = (EditText) findViewById(R.id.loginUserID);
inputPassword = (EditText) findViewById(R.id.loginPassword);
btnLogin = (Button) findViewById(R.id.btnLogin);
loginErrorMsg = (TextView) findViewById(R.id.login_error);
// Login button Click Event
btnLogin.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
String userid = inputUserID.getText().toString();
String password = inputPassword.getText().toString();
new MyAsyncTask().execute(userid, password);
}
});
}
}
DatabaseHandler.java：
package com.example.sabre8.library;
import java.util.HashMap;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHandler extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "adserve";
// Login table name
private static final String TABLE_LOGIN = "login";
// Login Table Columns names
private static final String KEY_USERID = "userid";
private static final String KEY_PASSWORD = "password";
private static final String KEY_FNAME = "fname";
private static final String KEY_MNAME = "mname";
private static final String KEY_LNAME = "lname";
private static final String KEY_POSITION = "position";
private static final String KEY_DEPARTMENT = "department";
private static final String KEY_ADMINTYPE = "admintype";
private static final String KEY_EMAIL = "email";
private static final String KEY_VERIFIER = "verifier";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_LOGIN_TABLE = "CREATE TABLE " + TABLE_LOGIN + "("
+ KEY_USERID + " TEXT PRIMARY KEY,"
+ KEY_PASSWORD + "TEXT,"
+ KEY_FNAME + " TEXT,"
+ KEY_MNAME + "TEXT,"
+ KEY_LNAME + "TEXT,"
+ KEY_POSITION+ "TEXT,"
+ KEY_DEPARTMENT + "TEXT,"
+ KEY_ADMINTYPE + " TEXT"
+ KEY_EMAIL + " TEXT UNIQUE,"
+ KEY_VERIFIER + "TEXT" + ")";
db.execSQL(CREATE_LOGIN_TABLE);
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_LOGIN);
// Create tables again
onCreate(db);
}
/**
* Storing user details in database
*/
public void addUser(String userid, String password, String fname, String mname, String lname, String position, String department, String admintype,String email, String verifier ) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_USERID, userid); // Userid
values.put(KEY_PASSWORD, password); //Pas
values.put(KEY_FNAME, fname); // Fname
values.put(KEY_MNAME, mname); // Mname
values.put(KEY_LNAME, lname); // Lname
values.put(KEY_POSITION, position); //Position
values.put(KEY_DEPARTMENT, department); // Department
values.put(KEY_ADMINTYPE, admintype);
values.put(KEY_EMAIL, email); // Department
values.put(KEY_VERIFIER, verifier);
// M]
// values.put(KEY_UID, uid); // Email
// values.put(KEY_CREATED_AT, created_at); // Created At
// Inserting Row
db.insert(TABLE_LOGIN, null, values);
db.close(); // Closing database connection
}
/**
* Getting user data from database
* */
public HashMap<String, String> getUserDetails(){
HashMap<String,String> userID = new HashMap<String,String>();
String selectQuery = "SELECT * FROM " + TABLE_LOGIN;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// Move to first row
cursor.moveToFirst();
if(cursor.getCount() > 0){
userID.put("userid", cursor.getString(1));
userID.put("password", cursor.getString(2));
userID.put("fname", cursor.getString(3));
userID.put("mname", cursor.getString(4));
userID.put("lname", cursor.getString(5));
userID.put("position", cursor.getString(6));
userID.put("department", cursor.getString(7));
userID.put("admintype", cursor.getString(8));
userID.put("email", cursor.getString(9));
userID.put("verifier", cursor.getString(10));
}
cursor.close();
db.close();
// return user
return userID;
}
/**
* Getting user login status
* return true if rows are there in table
* */
public int getRowCount() {
String countQuery = "SELECT * FROM " + TABLE_LOGIN;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int rowCount = cursor.getCount();
db.close();
cursor.close();
// return row count
return rowCount;
}
/**
* Re create database
* Delete all tables and create them again
* */
public void resetTables(){
SQLiteDatabase db = this.getWritableDatabase();
// Delete All Rows
db.delete(TABLE_LOGIN, null, null);
db.close();
}
}
UserFunctions.java:
package com.example.sabre8.library;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;
import android.content.Context;
public class UserFunctions {
private JSONParser jsonParser;
// Testing in localhost using wamp or xampp
// use http://10.0.2.2/ to connect to your localhost ie http://localhost/
private static String loginURL = "http://10.0.2.2/Adserve1/";
//private static String registerURL = "http://10.0.2.2/Sabre1/";
private static String login_tag = "login";
//private static String register_tag = "register";
// constructor
public UserFunctions(){
jsonParser = new JSONParser();
}
/**
* function make Login Request
* @param email
* @param password
* */
public JSONObject loginUser(String userid, String password){
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("tag", login_tag));
params.add(new BasicNameValuePair("userid", userid));
params.add(new BasicNameValuePair("password", password));
JSONObject json = jsonParser.makeHttpRequest(loginURL, "POST", params);
// return json
// Log.e("JSON", json.toString());
return json;
}
/**
* Function get Login status
**/
public boolean isUserLoggedIn(Context context){
DatabaseHandler db = new DatabaseHandler(context);
int count = db.getRowCount();
if(count > 0){
// user logged in
return true;
}
return false;
}
/**
* Function to logout user
* Reset Database
* */
public boolean logoutUser(Context context){
DatabaseHandler db = new DatabaseHandler(context);
db.resetTables();
return true;
}
}
我的logcat错误：
02-13 20：09：39.481：E / JSON Parser（1305）：解析数据时出错org.json.JSONException：Value
为了更好的衡量，我的DB_Functions.php：
<?php
class DB_Functions {
private $db;
//put your code here
// constructor
function __construct() {
require_once 'DB_Connect.php';
// connecting to database
$this->db = new DB_Connect();
$this->db->connect();
}
// destructor
function __destruct() {
}
/**
* Get user by email and password
*/
public function getUserByEmailAndPassword($userid, $password) {
$result = mysql_query("SELECT * FROM user_tb WHERE UserID = '$userid'") or die(mysql_error());
// check for result
$no_of_rows = mysql_num_rows($result);
if ($no_of_rows > 0) {
$result = mysql_fetch_array($result);
// check for password equality
$pass = $result['password'];
if ($pass == $password) {
// user authentication details are correct
return $result;
}
} else {
// user not found
return false;
}
}
/**
* Check user is existed or not
*/
public function isUserExisted($userid) {
$result = mysql_query("SELECT UserID from user_tb WHERE UserID = '$userid'");
$no_of_rows = mysql_num_rows($result);
if ($no_of_rows > 0) {
// user existed
return true;
} else {
// user not existed
return false;
}
}
}
?>
对于冗长的代码感到抱歉，但我被困住了。希望你能帮忙。
答案 0 :(得分：0)
JSON库无法解析来自服务器的响应，这就是它抛出JSONException的原因。无论出于何种原因，您的PHP脚本都没有返回有效的JSON。
首先，使用curl或其他HTTP工具向您的脚本发送请求并查看响应是什么。如果有任何PHP错误，您可能会在响应中看到它们的HTML代码。 Postman for Chrome非常适合调试Web服务。
然后，一旦您修复了PHP脚本的任何错误，您就可以使用JSONLint之类的工具来确保它返回的JSON有效。