iOS UiTextField限制输入和键盘关闭

Question

Hi i have created a UITextField and i'm wanting to restrict it to just 3 letters. and if its empty disable a button if not enable a button. does anyone know how to do this?

i've given it a go but it's not really working properly if i type 3 letters it shows 3 but wont close the keyboard.i can't help but feel theres a better way to do this.

heres what i've done

- (void)hideKeyboardAction {

    NSLog(@"Hide");

    if([self.playerName length] >= 4){
        [self.nameTextField resignFirstResponder];
    } else if([self.playerName length] < 3) {
        [self.addToScores setEnabled:FALSE];
    }
}

- (IBAction)hideKeyboard:(id)sender {

  [self hideKeyboardAction];
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    self.playerName = [textField.text stringByReplacingCharactersInRange:range withString:string];

    if([self.playerName length] <4 ){
        [self hideKeyboardAction];
    }

    if([self.playerName length] > 3){
        [self.addToScores setEnabled:FALSE];
    }

    BOOL shouldStayOpen = !([self.playerName length] > 3); 
    return shouldStayOpen;
}

Answer 1

You should not replace the text in textField:shouldChangeCharactersInRange:replacementString:. You should check the length of the text in textField, compare the length of the range and that of the replacementString and decide (return YES/NO) whether to replace or not. You can also enable/disable the button in this method, based on the calculated length of the text after replacement.

And there is no need to hide the keyboard, in my opinion.