I'm Trying to figure out the timing of the iOS Keyboard - iphone

Question

So here is the situation of the timing. I have a UILabel that I want to update every time the keyboard updates a UITextField. I have two UITextFields but only one is ever the first responder so don't worry about there being two I have them for back end purposes. The problem is the timing from the UILabel updating and the UITextField delegate function
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string;˚
The replacement string doesn't get added until YES is returned to by the above function. I need to update my labels either after this function is called or during this function. I can't seem to figure out how it will work. The UILabel is always one character behind. Below is my code in general for this section.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if([self.hiddenTextFieldForTimeMinutes.text length] == 2 && [self.hiddenTextFieldForTime.text length] == 2 && ![string isEqualToString:#""])
{
return NO;
}
[self syncTextFieldsMinutesAndHours: string];
// This returns the default Yes;
return YES;
}
- (void) setAccessoryLabel: (NSString *) hourString minutesString: (NSString *) minuteString
{
timeAccessoryLabel.text = [NSString stringWithFormat:#"%#:%#", hourString, minuteString];
}
- (void) syncTextFieldsMinutesAndHours: (NSString *) string
{
// These are the textFields
NSMutableString *hoursString = [NSMutableString stringWithFormat: #"%#", self.hiddenTextFieldForTime.text];
NSMutableString *minutesString = [NSMutableString stringWithFormat: #"%#", self.hiddenTextFieldForTimeMinutes.text];
if([self.hiddenTextFieldForTimeMinutes.text length] == 2 && ![string isEqualToString: #""])
{
[hoursString appendString: [NSString stringWithFormat:#"%c", [minutesString characterAtIndex:0]]];
[self.hiddenTextFieldForTime setText:[NSString stringWithFormat:#"%#", hoursString]];
[self.hiddenTextFieldForTimeMinutes setText: [self.hiddenTextFieldForTimeMinutes.text substringFromIndex:1]];
} else if([self.hiddenTextFieldForTimeMinutes.text length] == 2 && [string isEqualToString: #""])
{
// Hours has nothing in it
if([hoursString length] == 0)
{
return;
} else if([hoursString length] == 1)
{
// Since the timing of the add and remove of the string is done by return of the delegate we append the string to the beginning first then return.
[self.hiddenTextFieldForTimeMinutes setText: [NSString stringWithFormat:#"%c%#", [self.hiddenTextFieldForTime.text characterAtIndex:0], self.hiddenTextFieldForTimeMinutes.text]];
[self.hiddenTextFieldForTime setText:#""];
} else if ([hoursString length] == 2)
{
// Since the timing of the add and remove of the string is done by return of the delegate we append the string to the beginning first then return.
[self.hiddenTextFieldForTimeMinutes setText: [NSString stringWithFormat:#"%c%#", [self.hiddenTextFieldForTime.text characterAtIndex:1], self.hiddenTextFieldForTimeMinutes.text]];
[self.hiddenTextFieldForTime setText: [NSString stringWithFormat:#"%c", [self.hiddenTextFieldForTime.text characterAtIndex:0]]];
}
}
[self setAccessoryLabel: self.hiddenTextFieldForTime.text minutesString:self.hiddenTextFieldForTimeMinutes.text];
}

Answer 1

yes. The text of the textField in textField:shouldChangeCharactersInRange:replacementString: will still have the old value, because it only gets changed after you answered yes to the question if the text should change.
You have two options.
create the NSString that your textField will have after you returned YES yourself:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if([self.hiddenTextFieldForTimeMinutes.text length] == 2 && [self.hiddenTextFieldForTime.text length] == 2 && ![string isEqualToString:#""])
{
return NO;
}
NSString *realString = [textField.text stringByReplacingCharactersInRange:range withString:string];
[self syncTextFieldsMinutesAndHours: realString];
// This returns the default Yes;
return YES;
}
or add a IBAction that gets called after the editing took place:
- (void)viewDidLoad {
// your viewDidLoad implementation
[textField addTarget:self action:#selector(textFieldDidChange:) forControlEvents:UIControlEventEditingChanged];
}
- (IBAction)textFieldDidChange:(UITextField *)sender {
[self syncTextFieldsMinutesAndHours: sender.text];
}

Answer 2

After mulling for a few minutes, this could be a run loop issue. Try adding this before you call the method to update your UILabel:
[[NSRunLoop currentRunLoop] runUntilDate: [NSDate dateWithTimeIntervalSinceNow: 0.01]];
//update label
[self updateLabelWithText:foo andText:bar];
Or try using GCD:
dispatch_queue_t main_queue = dispatch_get_main_queue();
dispatch_async(queue, ^{
dispatch_async(main_queue, ^{
// UI Updates here
[self updateLabel...];
});
});