How can I add swipe gestures to 3 different UILabels?

Question

I'm new to XCODE - Objective-C and in my very first app I need to add to 3 different labels 2 swipe gestures (Up and down swipe).

To be more clear (for now i cannot add images) i have the 3 labels like this:

                           [label1].[label2][label3]

Min value for all labels is '0' Max value for label1 is '2', for label2 and label3 is '9' each one.

When I swipe down labels i need to decrease value and when i swipe up i need to decrease value.

How can I do this? in an example that I made before I did it but only works for 1 single UILabel.

Thanks a lot in advance. Regards.

Answer 1

You need to initialise 3 swipes, each label a swipe itself. I propose using tags to differ labels.

Here is the code that creates labels programmatically:

UILabel *label1 = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 100, 100)];
label1.text = @"Label 1";
label1.tag = 10;
label1.userInteractionEnabled = YES;
UISwipeGestureRecognizer *swipe1 = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipeLabel:)];
[label1 addGestureRecognizer:swipe1];

UILabel *label2 = [[UILabel alloc] initWithFrame:CGRectMake(50, 150, 100, 100)];
label2.text = @"Label 2";
label2.tag = 20;
label2.userInteractionEnabled = YES;
UISwipeGestureRecognizer *swipe2 = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipeLabel:)];
[label2 addGestureRecognizer:swipe2];

UILabel *label3 = [[UILabel alloc] initWithFrame:CGRectMake(50, 250, 100, 100)];
label3.text = @"Label 3";
label3.tag = 30;
label3.userInteractionEnabled = YES;
UISwipeGestureRecognizer *swipe3 = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipeLabel:)];
[label3 addGestureRecognizer:swipe3];

[self.view addSubview:label1];
[self.view addSubview:label2];
[self.view addSubview:label3];

The swipe method:

- (void)didSwipeLabel:(id)sender
{
    // Parse the swipe gesture
    UISwipeGestureRecognizer *swipe = sender;
    // Get the view that called swipe
    UILabel *swipedLabel = (UILabel *)swipe.view;
    // Switch tag
    switch (swipedLabel.tag) {
        case 10:
            NSLog(@"Swiped label 1");
            break;
        case 20:
            NSLog(@"Swiped label 2");
            break;
        case 30:
            NSLog(@"Swiped label 3");
            break;
        default:
            break;
    }
}

If you prefer to use Interface Builder, you can accomplish setting view's tag in the "Attributes Inspector" tab:

Don't forget to set userInteractionEnabled to YES. I left logical and direction verification up to you.