Custom Number Pad For iPad App

Question

I'm creating an in-house app for iPad running on iOS 8 (not for app store) and one of the requirements is a custom keyboard that replicates the iPad unlock/PIN code entry number pad.

I based my custom number pad on this project: https://github.com/lnafziger/Numberpad

In my project I have added a new UIView to the UIViewController so that I can replicate the dots that appear when a 4-digit PIN code is typed as below:

My problem is that I cannot get the targeting of the numbers correct when I tap them. My goal is that when I tap the numbers 0 to 9 that the first tap will put that number into the first text box and the second into the second etc. But I cannot get the taps on the number pad to register in any of the 4 available UITextFields.

[EDIT]

Here is that part of the code so far:

#pragma mark - KEYPAD IBACTIONS

// A number (0-9) was just pressed on the number pad
// Note that this would work just as well with letters or any other character and is not limited to numbers.
- (IBAction)numberpadNumberPressed:(UIButton *)sender {
    if (self.targetTextInput) {
        NSString *numberPressed  = sender.titleLabel.text;
        if ([numberPressed length] > 0) {
            UITextRange *selectedTextRange = self.targetTextInput.selectedTextRange;
            if (selectedTextRange) {
                [self textInput:self.targetTextInput replaceTextAtTextRange:selectedTextRange withString:numberPressed];
            }
        }
    }
}

// The delete button was just pressed on the number pad
- (IBAction)numberpadDeletePressed:(UIButton *)sender {
    if (self.targetTextInput) {
        UITextRange *selectedTextRange = self.targetTextInput.selectedTextRange;
        if (selectedTextRange) {
            // Calculate the selected text to delete
            UITextPosition  *startPosition  = [self.targetTextInput positionFromPosition:selectedTextRange.start offset:-1];
            if (!startPosition) {
                return;
            }
            UITextPosition  *endPosition    = selectedTextRange.end;
            if (!endPosition) {
                return;
            }
            UITextRange     *rangeToDelete  = [self.targetTextInput textRangeFromPosition:startPosition
                                                                               toPosition:endPosition];

            [self textInput:self.targetTextInput replaceTextAtTextRange:rangeToDelete withString:@""];
        }
    }
}

// The clear button was just pressed on the number pad
- (IBAction)numberpadClearPressed:(UIButton *)sender {
    if (self.targetTextInput) {
        UITextRange *allTextRange = [self.targetTextInput textRangeFromPosition:self.targetTextInput.beginningOfDocument
                                                                     toPosition:self.targetTextInput.endOfDocument];

        [self textInput:self.targetTextInput replaceTextAtTextRange:allTextRange withString:@""];
    }
}

// The done button was just pressed on the number pad
- (IBAction)numberpadDonePressed:(UIButton *)sender {
    if (self.targetTextInput) {
        [self.targetTextInput resignFirstResponder];
    }
}

- (BOOL)textFieldShouldEndEditing:(UITextField *)textField
{
    return YES;
}

- (BOOL)textViewShouldEndEditing:(UITextView *)textView
{
    return YES;
}

// Replace the text of the textInput in textRange with string if the delegate approves
- (void)textInput:(id <UITextInput>)textInput replaceTextAtTextRange:(UITextRange *)textRange withString:(NSString *)string {
    if (textInput) {
        if (textRange) {
            // Calculate the NSRange for the textInput text in the UITextRange textRange:
            int startPos                    = [textInput offsetFromPosition:textInput.beginningOfDocument
                                                                 toPosition:textRange.start];
            int length                      = [textInput offsetFromPosition:textRange.start
                                                                 toPosition:textRange.end];
            NSRange selectedRange           = NSMakeRange(startPos, length);

            if ([self textInput:textInput shouldChangeCharactersInRange:selectedRange withString:string]) {
                // Make the replacement:
                [textInput replaceRange:textRange withText:string];
            }
        }
    }
}

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

    switch ([passcode length]) {
        case 0:
            self.txtBulletField0.text = nil;
            self.txtBulletField1.text = nil;
            self.txtBulletField2.text = nil;
            self.txtBulletField3.text = nil;
            break;
        case 1:
            self.txtBulletField0.text = @"*";
            self.txtBulletField1.text = nil;
            self.txtBulletField2.text = nil;
            self.txtBulletField3.text = nil;
            break;
        case 2:
            self.txtBulletField0.text = @"*";
            self.txtBulletField1.text = @"*";
            self.txtBulletField2.text = nil;
            self.txtBulletField3.text = nil;
            break;
        case 3:
            self.txtBulletField0.text = @"*";
            self.txtBulletField1.text = @"*";
            self.txtBulletField2.text = @"*";
            self.txtBulletField3.text = nil;
            break;
        case 4:
            self.txtBulletField0.text = @"*";
            self.txtBulletField1.text = @"*";
            self.txtBulletField2.text = @"*";
            self.txtBulletField3.text = @"*";

            // Notify delegate a little later so we have a chance to show the 4th bullet
            [self performSelector:@selector(notifyDelegate:) withObject:passcode afterDelay:0];

            return NO;

            break;
        default:
            break;
    }

In the original project the number pad targeted one UITextField and put all the number taps into there. Now I want to have it automatically move between my 4 UITextFields (one UITextField should only accept 1 character and then move to the next UITextField). The numberpadNumberPressed method does not seem to trigger updating the text fields at all.

[END EDIT]

How would I do this?

Answer 1

This could be so simple.

Just keep the numbers that have been tapped in one mutable string variable. When a key is pressed, add the next number. If the delete key is pressed delete the last number, if any. That should be easy. E.g.

if (pinString.length < 4) {
   [pinString appendString:sender.titleLabel.text]
}

and

if (pinString.length) {
   [pinString deleteCharactersInRange:NSMakeRange(pinString.length-1,1)];
}

You are not editing the numbers in the text fields, so you should use labels instead. In the following, I assume you have given them the tags 101, 102, 103 and 104.

Then just do something like this:

for (UILabel *label in theFourTextLabels) {
   label.text = label.tag - 100 > pinString.length ? "" : "*";
}