check user is login or not in IOS - ios5

Question

I am making an IOS app in which I have some extra things for registered user so I made login form and it works perfectly but every time I run simulator I have to login so I just want to ask that how can I store the login user that when an registered user is login first time then login page opened but after login when user close their app and run again then its open next page from login.

Answer 1

use NSUserDefaults to store the flag variable to check the login status

Answer 2

For Saving Username and Password I will personally suggest to use Keychain as they are more safer than NSUserDefault in terms of security since Keychain stores data in encrypted form while NSUserDefault stores as plain text. If you still want to use NSUserDefault Here's the way
// create a standardUserDefaults variable
NSUserDefaults * standardUserDefaults = [NSUserDefaults standardUserDefaults];
// saving an NSString
[standardUserDefaults setObject:#"YES" forKey:#"Login"];
[standardUserDefaults synchronize];
//Check For Login
// create a standardUserDefaults variable
NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
// getting an NSString object
NSString *Isallowed = [standardUserDefaults stringForKey:#"Login"];
if(Isallowed == #"YES"){
// Process for login
}
else
{
}

Answer 3

// create a standardUserDefaults variable
NSUserDefaults * standardUserDefaults = [NSUserDefaults standardUserDefaults];
// saving an NSString
[standardUserDefaults setObject:#"YES" forKey:#"Login"];
[standardUserDefaults synchronize];
//Check For Login
// create a standardUserDefaults variable
NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
// getting an NSString object
NSString *Isallowed = [standardUserDefaults stringForKey:#"Login"];
if(Isallowed == #"YES"){
// Process for login
}
else
{
// Alert them for Not login
}

Answer 4

I'm gonna give you a comprehensive answer.
Don't use NSUserDefaults and don't store password it's a bad solution
NSUserDefaults data is not encrypted, it may cause security issue.
Let's create a structured user class instead
When the user logged in, you will need to make sure you have access to user data throughout the app so you can get the data on any screen when you need it.
To achieve this, we need to make a great structure to organize this properly. Remember that current user and another users are both "user" so we will use the same class.
Create a class and name it "EDUser" (you can choose other name if you want).
This class will contain a user information (either current user or other user).
More than that, this class will have capability to log the user in.
Here's a picture of what the class might look like:
class EDUser {
var firstName: String
var lastName: String?
var birthDate: NSDate?
init(firstName: String, lastName: String?, birthDate: NSDate?) {
self.firstName = firstName
self.lastName = lastName
self.birthDate = birthDate
}
}
// MARK: - Accessor
extension EDUser {
class var currentUser: EDUser? {
get {
return loadCurrentUserFromDisk()
}
set {
saveCurrentUserToDiskWithUser(newValue)
}
}
}
// MARK: - Log in and out
extension EDUser {
class func loginWithUsername(username: String,
andPassword password: String,
callback: (EDUser?, NSError) -> Void) {
// Access the web API
var parameters = [
"username": username,
"password": password
]
YourNetworkingLibrary.request(.POST,
"https://api.yourwebsite.com/login",
parameters: parameters).responseJSON {
response in
if response.statusCode == .Success {
let user = EDUser(firstName: response["firstName"],
lastName: response["lastName"],
birthDate: NSDate.dateFromString(response["birthDate"]))
currentUser = user
callback(currentUser, nil)
} else {
callback(nil, yourError)
}
}
}
class func logout() {
deleteCurrentUserFromDisk()
}
}
// MARK: - Data
extension EDUser {
class private func saveCurrentUserToDiskWithUser(user: EDUser) {
// In this process, you encode the user to file and store it
}
class private func loadCurrentUserFromDisk() -> EDUser? {
// In this process, you get the file and decode that to EDUser object
// This function will return nil if the file is not exist
}
class private func deleteCurrentUserFromDisk() {
// This will delete the current user file from disk
}
}
// MARK: - Helper
extension NSDate {
class func dateFromString(string: String) -> NSDate {
// convert string into NSDate
}
}
Use Case
Now with everything in place, we can use it like this
Non-blocking logging in process
EDUser.loginWithUsername(username: "edward#domain.com",
password: "1234") {
user, error in
if error == nil {
// Login succeeded
} else {
// Login failed
}
}
Logging out
EDUser.logout()
Check whether the user is logged in
if EDUser.currentUser != nil {
// The user is logged in
} else {
// No user logged in
// Show the login screen here
}
Get current user data on any screen
if let currentUser = EDUser.currentUser {
// do something with current user data
}
Store other user as object
let user = EDUser(firstName: "Edward",
lastName: "Anthony",
birthDate: NSDate())