CODEWITHSUNDEEP
iosobjective-c
Herbie999
Herbie999

Reputation: 315

How do I have text fade in to a UILabel?

Right now I have an IBAction for a button which generates a random number with each number assigned to display text in a UILabel. Rather than just appear, I would like the text to fade in or any other interesting animation would be cool too. Does anyone know a simple way to make this happen?

Right now I just use

labelMain.text = @"my text";

Upvotes: 11

Views: 14664

Answers (6)

levigroker
levigroker

Reputation: 2136

I know this is a bit stale (11 months old), but I think it's worth mentioning an alternative to the other approaches posted, which I feel is a better solution.

Make use of the UIView transitionWithView:duration:options:animations:completion class-level method, like this:

NSTimeInterval duration = 0.5f;
[UIView transitionWithView:labelMain
                  duration:duration
                   options:UIViewAnimationOptionTransitionCrossDissolve
                animations:^{
                  labelMain.text = @"new value";
                } completion:nil];

This will cross-fade from the previous value of labelMain.text to "new value".

This approach works on other view values as well, such as changing the image of a UIImageView, for instance.

See Apple's docs on the topic.

Upvotes: 31

Vinodh
Vinodh

Reputation: 5268

This will look like cross fade animation 

 [UIView animateWithDuration:0.5 delay:0 options:UIViewAnimationOptionCurveEaseOut
        animations:^{
    labelMain.alpha = 0;

        [UIView animateWithDuration:0.5 delay:0 options:UIViewAnimationOptionCurveEaseIn
        animations:^{ labelMain.alpha = 1;}
        completion:nil];

    } completion:nil];

Upvotes: 0

Vinayak Kini
Vinayak Kini

Reputation: 2919

The following code will give you fading effect on your label.

 - (IBAction)buttonClicked:(UIButton *)sender
  {
    labelMain.alpha = 0;

    [UIView animateWithDuration:0.5 delay:0 options:UIViewAnimationOptionCurveEaseIn
    animations:^{ labelMain.alpha = 1;}
    completion:nil];
 }

Upvotes: 27

XJones
XJones

Reputation: 21967

// fade out the current value
[UIView animateWithDuration:0.2
                      delay:0
                    options:0
                 animations:^{
                   labelMain.alpha = 0.0f;
                 }
                 completion:^(BOOL finished) {
                   // set the new value and fade in
                   labelMain.text = newValue;
                   [UIView animateWithDuration:0.2
                                         delay:0
                                       options:0
                                    animations:^{
                                      labelMain.alpha = 1.0f;
                                    }
                                    completion:nil];

                 }];

Upvotes: 0

IronMan
IronMan

Reputation: 1505

label.text = @"old text";
    [UIView animateWithDuration:0.4 animations:^{
        label.alpha = 0.0f;
    } completion:^(BOOL finished) {
        label.text = @"next text";
        [UIView animateWithDuration:0.4 animations:^{
            label.alpha = 1.0f;
        } completion:^(BOOL finished) {
            NSLog(@"finished transition");
        }];
    }];

Upvotes: 6

Simon M
Simon M

Reputation: 2941

Try this:

[labelMain setAlpha:0];
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.8];
[labelMain setAlpha:1];
[UIView commitAnimations];

Changing the duration is pretty simple - just adjust the value 0.8 in the code.

Upvotes: 1

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