Moving UITextField that is located under keyboard

Question

so like im sure every iOS programmer i ran into a problem, when trying to have a page full of UITextFields, it became evident that when the keyboard comes up it covers half of them. So i went to Apple's documentation and read all about it and wrote up the code for it, but it isn't working for me. Every time i run the view it crashes. Thanks in advance for your help.

.h file

 @interface NewUserViewController : UIViewController{

   } 

    - (IBAction)signMeUpButtonPressed:(id)sender;

    @property (weak, nonatomic) IBOutlet UITextField *activeField;
    @property (weak, nonatomic) IBOutlet UIScrollView *contentScrollView;
    @property (weak, nonatomic) IBOutlet UIButton *backButton;
    @property (weak, nonatomic) IBOutlet UILabel *firstNameLabel;
    @property (weak, nonatomic) IBOutlet UITextField *firstNameInput;
    @property (weak, nonatomic) IBOutlet UILabel *lastNameLabel;
    @property (weak, nonatomic) IBOutlet UITextField *lastNameInput;
    @property (weak, nonatomic) IBOutlet UILabel *usernameLabel;
    @property (weak, nonatomic) IBOutlet UITextField *usernameInput;
    @property (weak, nonatomic) IBOutlet UILabel *emailLabel;
    @property (weak, nonatomic) IBOutlet UITextField *emailInput;
    @property (weak, nonatomic) IBOutlet UILabel *passwordLabel;
    @property (weak, nonatomic) IBOutlet UITextField *setPasswordInput;
    @property (weak, nonatomic) IBOutlet UILabel *reenterPasswordLabel;
    @property (weak, nonatomic) IBOutlet UITextField *checkSetPasswordInput;
    @property (weak, nonatomic) IBOutlet UIButton *signMeUpButton;

All are connected to their outlets (except for active field. Im not sure where it belongs or what it should be connected to)

.m file

@implementation NewUserViewController

@synthesize contentScrollView;
@synthesize activeField;
@synthesize firstNameLabel, lastNameLabel, usernameLabel, emailLabel, passwordLabel, reenterPasswordLabel;
@synthesize firstNameInput, lastNameInput, usernameInput, emailInput, setPasswordInput, checkSetPasswordInput;
@synthesize backButton, signMeUpButton;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
    // Custom initialization
}
return self;
}

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
activeField = textField;
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
activeField = nil;
}

- (void)registerForKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWasShown:)
                                                 name:UIKeyboardDidShowNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillBeHidden:)
                                                 name:UIKeyboardWillHideNotification object:nil];

}

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWasShown:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
    contentScrollView.contentInset = contentInsets;
    contentScrollView.scrollIndicatorInsets = contentInsets;

    // If active text field is hidden by keyboard, scroll it so it's visible
    // Your application might not need or want this behavior.
    CGRect aRect = self.view.frame;
    aRect.size.height -= kbSize.height;
    if (!CGRectContainsPoint(aRect, activeField.frame.origin) ) {
        CGPoint scrollPoint = CGPointMake(0.0, activeField.frame.origin.y-kbSize.height);
        [contentScrollView setContentOffset:scrollPoint animated:YES];
    }
}

// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
    UIEdgeInsets contentInsets = UIEdgeInsetsZero;
    contentScrollView.contentInset = contentInsets;
    contentScrollView.scrollIndicatorInsets = contentInsets;
}

- (IBAction)signMeUpButtonPressed:(id)sender {
} 

Answer 1

Try this:

- (void)keyboardWasShown:(NSNotification *)notification {



    NSDictionary* userInfo = [notification userInfo];

    CGRect keyboardEndFrame;

    [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardEndFrame];
//offset is global
    offset = contentScrollView.contentOffset;

    CGRect viewFrame = contentScrollView.frame;
    CGRect keyboardFrame = [self convertRect:keyboardEndFrame toView:nil];
    viewFrame.size.height -= keyboardFrame.size.height;
    contentScrollView.frame = viewFrame;

    UITextField *current = (UITextField *)[self findFirstResponder];
    CGRect textFieldRect = current.frame;

    [contentScrollView scrollRectToVisible:textFieldRect animated:YES];

}
- (UIView *)findFirstResponder {
    for (UIView *subView in  scrollView.subviews) {
        if ([subView isFirstResponder]){
            return subView;
        }
    }
    return nil;
}

- (void) keyboardWillBeHidden:(NSNotification *)notification {

//scrollViewFrame is global the first frame of you scrollview
    contentScrollView.frame = scrollViewFrame;

    contentScrollView.contentOffset =offset;


}

this is not a complete code this is just a little logic of performing what you want to do.