我正在尝试实现一个android注册表单，当用户尝试注册应用程序只是崩溃和关闭时，该表单不起作用，但是，用户信息确实会插入到数据库中。
一旦我给dubbged应用程序，我可以看到josn返回一个空值，但是，请你帮我解决这个问题，因为下面显示json返回null值。
this = {UserFunctions@831721419648}
jsonParser = {JSONParser@831721420368}
json = null
params = {ArrayList@831721420384} size = 6
0 = {BasicNameValuePair@831721420544} "tag=register"
value = {String@831721419456} "register"
name = {String@831694602352} "tag"
1 = {BasicNameValuePair@831721420688} "fname=lawson"
name = {String@831697794824} "fname"
value = {String@831721366152} "lawson"
2 = {BasicNameValuePair@831721420712} "lname=Junior"
name = {String@831697794888} "lname"
value = {String@831721366248} "Junior"
3 = {BasicNameValuePair@831721420736} "email=lawson123@ymaill.com"
name = {String@831697795120} "email"
value = {String@831721366368} "lawson123@ymaill.com"
4 = {BasicNameValuePair@831721420760} "uname=junior_l"
name = {String@831697795056} "uname"
value = {String@831721366488} "junior_l"
5 = {BasicNameValuePair@831721420784} "password=Lampard8"
name = {String@831694110784} "password"
value = {String@831721366584} "Lampard8"
jsonParser = {JSONParser@831721420368}
registerURL= {String@831721419264} "http://192.168.24.4/bradvisor_login_api/"
Log cat错误消息
{"tag":"register","success":1,"error":0,"user":{"fname":"crisnfg","lname":"nawadv","email":"christina@gmail.com","uname":"crisitina","uid":"56e99196d80403.95127534","created_at":"2016-03-16 17:02:14"}}
03-16 17:01:48.945 8482-11204/com.bradvisor.bradvisor E/Buffer Error: Error converting result org.json.JSONException: Value 2016-03-16 of type java.lang.String cannot be converted to JSONObject
03-16 17:01:48.948 8482-8482/com.empier E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.empier, PID: 8482
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String org.json.JSONObject.getString(java.lang.String)' on a null object reference
at com.empier.Register$ProcessRegister.onPostExecute(Register.java:209)
at com.empier.Register$ProcessRegister.onPostExecute(Register.java:169)
03-16 19:34:03.519 19048-19048/com.empier D/debug_tag: false
03-16 19:34:10.110 19048-19048/com.empier D/debug_tag: false
03-16 19:34:10.198 19048-19048/com.empier D/debug_tag: false
03-16 19:35:42.417 19048-19048/com.empier D/debug_tag: false
03-16 19:35:43.093 19048-19048/com.empier D/debug_tag: false
03-16 19:37:07.778 19048-19048/com.empier D/debug_tag: false
03-16 19:38:22.195 19048-19048/com.empier D/debug_tag: false
03-16 19:40:23.161 19048-19048/com.empier D/debug_tag: false
03-16 19:42:56.833 24951-24951/com.empier D/debug_tag: true
03-16 19:58:16.518 29411-29411/? D/debug_tag: true
Register.Java代码
public class Register extends Activity {
/**
* JSON Response node names.
**/
private static String KEY_SUCCESS = "success";
private static String KEY_UID = "uid";
private static String KEY_FIRSTNAME = "fname";
private static String KEY_LASTNAME = "lname";
private static String KEY_USERNAME = "uname";
private static String KEY_EMAIL = "email";
private static String KEY_CREATED_AT = "created_at";
private static String KEY_ERROR = "error";
/**
* Defining layout items.
**/
EditText inputFirstName;
EditText inputLastName;
EditText inputUsername;
EditText inputEmail;
EditText inputPassword;
ImageButton btnRegister;
TextView registerErrorMsg;
/**
* Called when the activity is first created.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.register);
/**
* Defining all layout items
**/
inputFirstName = (EditText) findViewById(R.id.fname);
inputLastName = (EditText) findViewById(R.id.lname);
inputUsername = (EditText) findViewById(R.id.uname);
inputEmail = (EditText) findViewById(R.id.email);
inputPassword = (EditText) findViewById(R.id.pword);
btnRegister = (ImageButton) findViewById(R.id.Registerbtn);
registerErrorMsg = (TextView) findViewById(R.id.register_error);
/**
* Register Button click event.
* A Toast is set to alert when the fields are empty.
* Another toast is set to alert Username must be 5 characters.
**/
btnRegister.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if ( ( !inputUsername.getText().toString().equals("")) && ( !inputPassword.getText().toString().equals("")) && ( !inputFirstName.getText().toString().equals("")) && ( !inputLastName.getText().toString().equals("")) && ( !inputEmail.getText().toString().equals("")) )
{
if ( inputUsername.getText().toString().length() > 4 ){
NetAsync(view);
}
else
{
Toast.makeText(getApplicationContext(),
"Username should be minimum 5 characters", Toast.LENGTH_SHORT).show();
}
}
else
{
Toast.makeText(getApplicationContext(),
"One or more fields are empty", Toast.LENGTH_SHORT).show();
}
}
});
}
/**
* Async Task to check whether internet connection is working
**/
private class NetCheck extends AsyncTask<String,String,Boolean>
{
private ProgressDialog nDialog;
@Override
protected void onPreExecute(){
super.onPreExecute();
nDialog = new ProgressDialog(Register.this);
nDialog.setMessage("Loading..");
nDialog.setTitle("Checking Network");
nDialog.setIndeterminate(false);
nDialog.setCancelable(true);
nDialog.show();
}
@Override
protected Boolean doInBackground(String... args){
/**
* Gets current device state and checks for working internet connection by trying Google.
**/
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnected()) {
try {
URL url = new URL("http://www.google.com");
HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
urlc.setConnectTimeout(3000);
urlc.connect();
if (urlc.getResponseCode() == 200) {
return true;
}
} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return false;
}
@Override
protected void onPostExecute(Boolean th){
if(th == true){
nDialog.dismiss();
new ProcessRegister().execute();
}
else{
nDialog.dismiss();
registerErrorMsg.setText("Error in Network Connection");
}
}
}
private class ProcessRegister extends AsyncTask<String, String, JSONObject> {
/**
* Defining Process dialog
**/
private ProgressDialog pDialog;
String email,password,fname,lname,uname;
@Override
protected void onPreExecute() {
super.onPreExecute();
inputUsername = (EditText) findViewById(R.id.uname);
inputPassword = (EditText) findViewById(R.id.pword);
fname = inputFirstName.getText().toString();
lname = inputLastName.getText().toString();
email = inputEmail.getText().toString();
uname= inputUsername.getText().toString();
password = inputPassword.getText().toString();
pDialog = new ProgressDialog(Register.this);
pDialog.setTitle("Contacting Servers");
pDialog.setMessage("Registering ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected JSONObject doInBackground(String... args) {
UserFunctions userFunction = new UserFunctions();
JSONObject json = userFunction.registerUser(fname, lname, email, uname, password);
return json;
}
@Override
protected void onPostExecute(JSONObject json) { Log.d("debug_tag", json == null ? "true" : "false");
try {
if (json.getString(KEY_SUCCESS) != null) {
registerErrorMsg.setText("");
String res = json.getString(KEY_SUCCESS);
String red = json.getString(KEY_ERROR);
if(Integer.parseInt(res) == 1){
pDialog.setTitle("Getting Data");
pDialog.setMessage("Loading Info");
registerErrorMsg.setText("Successfully Registered");
DatabaseHandler db = new DatabaseHandler(getApplicationContext());
JSONObject json_user = json.getJSONObject("user"); Log.d("debug_tag", "User json :: " + json_user==null ? "true": "false");
/**
* Removes all the previous data in the SQlite database
**/
UserFunctions logout = new UserFunctions();
logout.logoutUser(getApplicationContext());
db.addUser(json_user.getString(KEY_FIRSTNAME),json_user.getString(KEY_LASTNAME),json_user.getString(KEY_EMAIL),json_user.getString(KEY_USERNAME),json_user.getString(KEY_UID),json_user.getString(KEY_CREATED_AT));
/**
* Stores registered data in SQlite Database
* Launch Registered screen
**/
Intent registered = new Intent(getApplicationContext(), Registered.class);
/**
* Close all views before launching Registered screen
**/
registered.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
pDialog.dismiss();
startActivity(registered);
finish();
}
else if (Integer.parseInt(red) ==2){
pDialog.dismiss();
registerErrorMsg.setText("User already exists");
}
else if (Integer.parseInt(red) ==3){
pDialog.dismiss();
registerErrorMsg.setText("Invalid Email id");
}
}
else{
pDialog.dismiss();
registerErrorMsg.setText("Error occurred in registration");
}
} catch (JSONException e) {
e.printStackTrace();
}
}}
public void NetAsync(View view){
new NetCheck().execute();
}}
Userfunction.java代码
//URL of the PHP API
private static String loginURL = "http://192.168.85.1/bradvisor_login_api/";
private static String registerURL = "http://192.168.85.1/bradvisor_login_api/";
private static String forpassURL = "http://192.168.85.1/bradvisor_login_api/";
private static String chgpassURL = "http://192.168.85.1/bradvisor_login_api/";
private static String login_tag = "login";
private static String register_tag = "register";
private static String forpass_tag = "forpass";
private static String chgpass_tag = "chgpass";
/**
* Function to Register
**/
public JSONObject registerUser(String fname, String lname, String email, String uname, String password){
// Building Parameters
List params = new ArrayList();
params.add(new BasicNameValuePair("tag", register_tag));
params.add(new BasicNameValuePair("fname", fname));
params.add(new BasicNameValuePair("lname", lname));
params.add(new BasicNameValuePair("email", email));
params.add(new BasicNameValuePair("uname", uname));
params.add(new BasicNameValuePair("password", password));
JSONObject json = jsonParser.getJSONFromUrl(registerURL, params);
return json;
}
的index.php
<?php
/*
PHP API for Login, Register, Changepassword, Resetpassword Requests and for Email Notifications.
*/
require_once 'mailer.php';
if (isset($_POST['tag']) && $_POST['tag'] != '')
{
// Include Database handler
require_once 'include/DB_Functions.php';
$db = new DB_Functions();
// response Array
$response = array("tag" => $_POST['tag'], "success" => 0, "error" => 0);
// check for tag type
switch($_POST['tag'])
{
case 'login':
// Request type is check Login
$email = $_POST['email'];
$password = $_POST['password'];
// check for user
$user = $db->getUserByEmailAndPassword($email, $password);
if ($user != false)
{
// user found
// echo json with success = 1
$response["success"] = 1;
$response["user"]["fname"] = $user["firstname"];
$response["user"]["lname"] = $user["lastname"];
$response["user"]["email"] = $user["email"];
$response["user"]["uname"] = $user["username"];
$response["user"]["uid"] = $user["unique_id"];
$response["user"]["created_at"] = $user["created_at"];
}
else
{
// user not found
// echo json with error = 1
$response["error"] = 1;
$response["error_msg"] = "Incorrect email or password!";
}
break;
case 'chgpass':
$email = $_POST['email'];
$newpassword = $_POST['newpas'];
$hash = $db->hashSSHA($newpassword);
$encrypted_password = $hash["encrypted"]; // encrypted password
$salt = $hash["salt"];
if ($db->isUserExisted($email))
{
$user = $db->forgotPassword($email, $encrypted_password, $salt);
if ($user)
{
$response["success"] = 1;
$subject = "Change Password Notification";
$message = "Hello $fname,\n\nYour Password is successfully changed.\n\nRegards,\nBradVisor Team.";
send_email($subject, $message, $email);
}
else
{
$response["error"] = 1;
}
// user is already existed - error response
}
else
{
$response["error"] = 2;
$response["error_msg"] = "User not exist";
}
break;
case 'forpass':
$email = $_POST['forgotpassword'];
$randomcode = $db->random_string();
$hash = $db->hashSSHA($randomcode);
$encrypted_password = $hash["encrypted"]; // encrypted password
$salt = $hash["salt"];
if ($db->isUserExisted($email))
{
$user = $db->forgotPassword($email, $encrypted_password, $salt);
if ($user)
{
$response["success"] = 1;
$subject = "Password Recovery";
$message = "Hello $fname,\n\nYour Password is successfully changed. Your new Password is $randomcode . Login with your new Password and change it in the User Panel.\n\nRegards,\nBradVisor Team.";
send_email($subject, $message, $email);
}
else
{
$response["error"] = 1;
}
// user is already existed - error response
}
else
{
$response["error"] = 2;
$response["error_msg"] = "User not exist";
}
break;
case 'register':
// Request type is Register new user
$fname = $_POST['fname'];
$lname = $_POST['lname'];
$email = $_POST['email'];
$uname = $_POST['uname'];
$password = $_POST['password'];
// check if user is already existed
if ($db->isUserExisted($email))
{
// user is already existed - error response
$response["error"] = 2;
$response["error_msg"] = "User already existed";
}
else if(!$db->validEmail($email))
{
$response["error"] = 3;
$response["error_msg"] = "Invalid Email Id";
}
else
{
// store user
$user = $db->storeUser($fname, $lname, $email, $uname, $password);
if ($user)
{
// user stored successfully
$response["success"] = 1;
$response["user"]["fname"] = $user["firstname"];
$response["user"]["lname"] = $user["lastname"];
$response["user"]["email"] = $user["email"];
$response["user"]["uname"] = $user["username"];
$response["user"]["uid"] = $user["unique_id"];
$response["user"]["created_at"] = $user["created_at"];
$subject = "Registration";
$message = "Hello $fname,\n\nYou have successfully registered to our service.\n\nRegards,\nAdmin.";
$name = $user['firstname'] . ' ' . $user['lastname'];
send_email($subject, $message, $email, $name);
}
else
{
// user failed to store
$response["error"] = 1;
$response["error_msg"] = "JSON Error occured in Registartion";
}
}
break;
default:
$response["error"] = 3;
$response["error_msg"] = "JSON ERROR";
}
echo json_encode($response);
}
else
{
echo "BradVisor Login API";
}
?>
userfunction.php
/**
* Adding new user to mysqli database
* returns user details
*/
public function storeUser($fname, $lname, $email, $uname, $password) {
$uuid = uniqid('', true);
$hash = $this->hashSSHA($password);
$encrypted_password = $hash["encrypted"]; // encrypted password
$salt = $hash["salt"]; // salt
$result = mysqli_query($this->db,"INSERT INTO `users`(`unique_id`, `firstname`, `lastname`, `username`, `email`, `encrypted_password`, `salt`, `created_at`) VALUES('$uuid', '$fname', '$lname', '$uname', '$email', '$encrypted_password', '$salt', NOW())") or die(mysqli_error($db));
// check for successful store
if ($result) {
// get user details
$uid = mysqli_insert_id($this->db); // last inserted id
$result = mysqli_query($this->db, "SELECT * FROM users WHERE uid = $uid") or die(mysqli_error($this->db));
// return user details
return mysqli_fetch_array($result);
} else {
return false;
}
}
Log cat错误消息
{"tag":"register","success":1,"error":0,"user":{"fname":"crisnfg","lname":"nawadv","email":"christina@gmail.com","uname":"crisitina","uid":"56e99196d80403.95127534","created_at":"2016-03-16 17:02:14"}}
03-16 17:01:48.945 8482-11204/com.bradvisor.bradvisor E/Buffer Error: Error converting result org.json.JSONException: Value 2016-03-16 of type java.lang.String cannot be converted to JSONObject
03-16 17:01:48.948 8482-8482/com.empier E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.empier, PID: 8482
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String org.json.JSONObject.getString(java.lang.String)' on a null object reference
at com.empier.Register$ProcessRegister.onPostExecute(Register.java:209)
at com.empier.Register$ProcessRegister.onPostExecute(Register.java:169)
03-16 19:34:03.519 19048-19048/com.empier D/debug_tag: false
03-16 19:34:10.110 19048-19048/com.empier D/debug_tag: false
03-16 19:34:10.198 19048-19048/com.empier D/debug_tag: false
03-16 19:35:42.417 19048-19048/com.empier D/debug_tag: false
03-16 19:35:43.093 19048-19048/com.empier D/debug_tag: false
03-16 19:37:07.778 19048-19048/com.empier D/debug_tag: false
03-16 19:38:22.195 19048-19048/com.empier D/debug_tag: false
03-16 19:40:23.161 19048-19048/com.empier D/debug_tag: false
03-16 19:42:56.833 24951-24951/com.empier D/debug_tag: true
03-16 19:58:16.518 29411-29411/? D/debug_tag: true
调试应用程序时，我可以看到json从服务器端返回一个空值。
userFunction = {UserFunctions@831722144728}
jsonParser = {JSONParser@831722145448}
json= null
lname = {String@831722145448} "jones"
email = {String@831722145448} "vincejames@yahoo.com"
uname = {String@831722145448} "JonesVince"
password = {String@831722145448} "Lion123456"
fname = {String@831722145448} "Vince"
我认为这是PHP方面的问题。能帮助你解决我目前面临的问题吗？
答案 0 :(得分：0)
在此响应中假设了以下代码片段，
{
"tag": "register",
"success": 1,
"error": 0,
"user": {
"fname": "crisnfg",
"lname": "nawadv",
"email": "christina@gmail.com",
"uname": "crisitina",
"uid": "56e99196d80403.95127534",
"created_at": "2016-03-16 17:02:14"
}
}
是的，你必须在try block下写这个并捕获例外
/**
* instantiate JsonObject with your response
* */
JSONObject jsonObject = new JSONObject("your json response");
String tag = jsonObject.getString("tag");
String success = jsonObject.getString("success");
String error = jsonObject.getString("error");
/**
* This is how you can read nested JsonObject {user}
* */
JSONObject user_JsonObject = jsonObject.getJSONObject("user");
String fname = user_JsonObject.getString("fname");
String lname = user_JsonObject.getString("lname");
String email = user_JsonObject.getString("email");
String uname = user_JsonObject.getString("uname");
String uid = user_JsonObject.getString("uid");
String created_at = user_JsonObject.getString("created_at");