In developing my current iPhone application, I'm having issues handling the login, logout functionality of presenting views.
I'd like to have my application have the following flow, but I cannot seem to figure out the proper viewcontroller setup:
When a user is not logged in, a login screen is immediately presented. Upon a successful login, the main application is displayed. The main application is a TabBarController. When returning back to the application, if you have already logged in, the login window will not display, but immediately go into the main tab bar. Once in the app, you can "logout" and it will take you back to the login scren.
Please let me know if I need to go into further detail. There are a few other questions on here that are similar but not exactly what I'm looking for.
Thanks!
I would consider two ways of doing this:
have the login screen be a modal view controller that pops over the main UI.
e.g.
if (currentCredentials == nil) [self presentModalViewController:loginView animated:YES];
or alternately, handle switching between views using your app delegate.
Related
I am designing an iphone application in objective C.
As of now, I have a UINavigationController in the beginning of my application
and rest of the navigation was being handled from it.
Now I want to insert a login screen when the application is loaded.
How do I make it independent of my rest of the application ?
i.e. As of now, I created a LoginViewController and added it to the NavigationViewController
of my app. When the user successfully logs in, the application continues with the next screen being pushed into the Navigation Controller.
But the problem with this approach is that, I can still go back to the initial login screen from the navigation item.
I have tried to hide the navigation bar from the first screen after login, but it removes the navigation bar from each of the subsequent screens.
The only working solution I can think of is that, I should manually hide the navigation bar in the start screen and make it visible in the subsequent screens.
Is there any other sane approach ?
I'd probably do your nav controller disregarding the login screen, and then present the login screen using presentModalViewController:animated:
present your LoginViewController in viewDidLoad for the the navigationController once the user login you dismiss it and continue your screen's flow as you want. also you can store that user login your app in the NSUserDefault so you can check this value and present the loginView in case he didn't login otherwise you show the navigation screen as normal
If the user have not login in the app show LoginViewController and don't allow the user to go to navigation controller till then. Once login don't show LoginViewController directly show navigation controller so that user dont have to sign again and again.. To store user login information use NSUserDefaults. Retrieve the info at loading of the app and display controllers accordingly.
Cheers
You need to store in UserDefaults some value - auto login / did login and when app is start you check this value if user isn`t in system u need to create login view controller and present it modaly.
Before your first view appear u need something like this -
BOOL didLogin = [[NSUserDefaults standardUserDefaults]boolForKey:#"isLogin"];
if (!didLogin) {
LoginViewController *loginVC = [[LoginViewController alloc]init];
[self presentModalViewController:loginVC animated:NO];
}
and when user is login you need to save value in user defaults
[[NSUserDefaults standardUserDefaults] setBool:YES forKey:#"isLogin"];
if you vant auto login feature you must store password in keychain
I would suggest to hide back button at your firstviewcontroller and unhide in rest all viewcontrollers.
-(void)viewWillAppear:(BOOL)animated {
self.navigationItem.hidesBackButton=YES;
}
Otherwise another solution is that present the loginviewcontroller in the viewDidLoad method of your firstviewcontroller and as login completes dismiss the presented logincontroller on login button.
Even its the standard method to implement, all apps having login facility would have this type of flow.
Hope this will help you out.
I have been searching the net, and i have found many very good examples on how to create a login page for your iPhone app. However... none of then meets my demands, an since i am new to iPhone development( i know java / c / C++ and objective-c), so the programming itself is not the issue.. The issue is where to put the code and what design patterns to use..
My app is a basic tabbar controller with 3 tabs that could contain navigation controllers, but that is not important.. it is the part before the tabbar controller i am interrested in, namely the need to authenticate the user towards a Lotus Domino Server. I have the authenification code working, so that is not the issue either..
By the way, i am concentrating on IOS5 and using storyboards..
Where do i put the "check if user is still authenticated" code ? The domino server will log the user out after 1 hour, so if the user has the app open(in background) then the code that downloads data will die if the user is not told that the session has expired..
So here is what i would like..
When the app launches, show the login page. This is working for now with the Login View Controller as initial controller, and a modal segue to the tabbar controller..
Next time the App is launched(either from background or from new is user has closed it completely), check if username and password is stored in userdefaults, and then just login in background, and if that fails(password has changed or another failure) then show the login view controller again..
So to sum up, where do i put the "part 2" code ? I have a seperate authenticator class that is using delegates, and i can use this class to perform the authentification, and the it will answer back if all is good.
Do i put this in the AppDelegate code ? If i put it in one of the tabbar viewcontrollers, then there might be an issue with the user having tab2 open when launching after 2 hours, and if the check is in tab1, then tab 2 will fail.. Should i put the code in ALL the tabbar viewcontrollers ? Naaa, that is ugly..
I am leaning towards the AppDelegate(appdidbecomeactive), but can that be used as delegate in my authenticator class ?
That was a bit long, sorry for that, but i needed to explain my problem fully so people would understand what i need..
Thank you for your help.. This is my first post, but this forum is fantastic :)
I'd definitely put both part one and part two code in the AppDelegate.
This allows you to create the appropriate viewcontroller at app start and remove the tabbarcontroller from within the AppDelegate if the authentication times out etc.
I'm not sure about your modal segue to a tabbarcontroller though (I'm not familiar with storyboards yet though). Modal implies you wouldn't be able to present any other view modally on top of the tabbar controller. I think it sounds like it would be much more appropriate to create your logincontroller and tabbarcontroller programmatically and add/remove them directly in your application’s main window as needed from your AppDelegate.
I would tell the AppDelegate to check the login status very time the tab is changed or data loaded.
In my app there is authentication required, so when you launch one of the tabs on tab bar, "class A" checks are there credentials saved if not, "class B" modal view controller with fields to login launches.
So my question is : in which method in class A (loadView, viewWillAppear or maybe in another one) should be implemented checking if there are credentials saved and other stuff described above.
And my additional second question is:
is pushing modalviewcontroller correct way to show login screen, or i should do that differently?
Thank you for reply guys.
OH ! One More Thinh
And one more thing. I've done implementing LoginView by adding delegate and presenting ModalVC (Harkonian the Piquant's method). But in my tab bar app i have got very confusing problem. I mean when user taps login button (assume that everything was correct and he's able to secured data) how PROPERLY switch to tab where is secured info. I mean previously selected tab.
i did it by adding in
-(IBAction) login {
//some code
self.tabBarController.selectedIndex =1;
And it seem to work good but is it correct ?
I have a very similar use case in my app -- it requires a passcode to authenticate. After a lot of testing and tweaking I found the following design to be the best approach:
Don't use class A to launch your credentials VC -- use the app delegate instead.
For security purposes, typically you'll want the credentials VC to show before the user can view the underlying view. It's much easier to handle this in the app delegate than in a VC. In addition, you need to consider what happens when your app is backgrounded -- a screen shot is taken of the current state of the app. If you are using viewController A to show the credentials view, when the app relaunches the user will be able to see whatever sensitive information was visible on app close until the app finishes launching and VC A presents the credentials VC.
Don't insert your credentials view into an existing ViewController -- use a new UIWindow instead.
You don't ever want any other view to be able to sit on top of your credentials view. Ever. Even views that would normally always be on top, like UIAlertView. The easiest way to achieve this is to have a special UIWindow just for your credentials view. Show this window and hide the primary app window whenever you need to display the credentials view.
How does this approach look in practice?
If you are at all interested in how well this design works, you can check out the passcode feature in Audiotorium Notes for iPad. I spent a lot of time with this design to make sure it was as secure as possible.
If you have any specific implementation quests feel free to ask and I'll try to answer them.
I'm writing an app that will allow iPhone users to login to their accounts. Once logged in the user can pull information, change passwords, change other types of data via webservices. I'm new to iPhone programming and I'm a bit confused on my viewController setup to handle this. What I would like to do is the following;
1) if the user is NOT logged in - display a view which takes up the entire screen displaying my login/password text fields etc. ( I will have some conditionals set in place checking to see if the user has u/p saved in a plist)
2) if user is logged in or once the user logs in, remove the current full size view and load the tabBar view. If the user logs out then the main login view will load.
I will need two viewControllers for this particular scenario? I've read a great deal on view controllers. Read all of the Apple documentation but I still get confused since there are so many options/methods to use.
As always I thank you in advance.
T
Just one of many possible options:
Create LoginViewController and UITabBarViewController. Application delegate will check on start-up whether it already has user's credentials and show the appropriate controller
if ([dataModel hasUserCredentials])
[window addSubview:[tabControlle view]];
else
[window addSubview:[loginController view]];
LoginViewController performs log in and notifies app delegate:
- (void) loginComplete
{
// XXX animation?
// XXX view(Will/Did)(Appear/Dosappear) and all the stuff,
[[loginContoller view] removeFromSuperview];
[window addSubview:[tabController view]];
}
Here is how I would do it:
The tab bar controller is your main view controller. You initialize it first (in the main NIB file) and add it to the window in your app delegate.
In application:didFinishLaunchingWithOptions:, you check whether the user is already logged in or not. If not, you immediately present your login screen as a modal view controller. If you do this without animation, the user will not notice that the tab bar controller is already present underneath.
When the user logs in, you dismiss the modal view controller and your tab bar UI becomes visible.
You should look at creating a Navigation-Based application. This will have a UINavigationController built in. You can use that to control your windows.
I'm currently working on an iPhone app.
This app has a login screen, also a signup screen.
After the user has successfully signed up, I dismiss the signup view, then the app automatically logs in using the created account. After which, the login view is dismissed, showing the main view.
I'm trying to modify this by immediately dismissing the login view, since I already have the account details of the user when the signup is successful. Basically, the ideal flow is: after the user successfully signs up, I save the username and password in a singleton class, then dismiss the signup view. When I get to the parent view (which is the login screen), I have a variable that checks if there was a successful signup. If that variable is true, I want to immediately dismiss the login view.
However, I come across this error message: Data Formatters temporarily unavailable, will re-try after a 'continue'. (Unknown error loading shared library "/Developer/usr/lib/libXcodeDebuggerSupport.dylib")
I'm not really sure why this happens. I have no problems dismissing the login view when I go through the actual login procedure - which of course also dismisses the login view if the user inputs a correct username and password.
I'm not exactly sure, but I'm starting to think that the iPhone cannot handle dismissing 2 view controllers almost at the same time.
Is it possible that I'm dismissing the login view too quickly? Is that a factor? Is there anyway for me to be able to dismiss 2 view controllers almost simultaneously without coming across this error message?
It seems likely that dismissing 2 UIViewControllers at the same time is the cause of this error (I have seen it for various other reasons, including running short of memory).
Try a different flow, where you check for the saved values first, then load your main view if valid, or the login view if not. I do this in one app, and it works fine.