Fade In Fade Out Animation

Question

Here is some code I struggle with for a while.

If you start the fade in animation, the label text fades in. If I start the fade out animation the the label text fades ou

Answer 1

I strongly suggest you use a generic implementation so you can reuse the code whenever you need the fade effect again.

You should create an UIView extension:

UIView+Animations.h

#import 

@interface UIView (Animations)

- (void)fadeInWithCompletion:(void (^ __nullable)(BOOL finished))completion;
- (void)fadeOutWithCompletion:(void (^ __nullable)(BOOL finished))completion;;

@end

UIView+Animations.m

#import "UIView+Animations.h"

@implementation UIView (Animations)

- (void)fadeInWithCompletion:(void (^ __nullable)(BOOL finished))completion {
    [UIView animateWithDuration:2 animations:^{
        [self setAlpha:1];
    } completion:completion];
}

- (void)fadeOutWithCompletion:(void (^ __nullable)(BOOL finished))completion {
    [UIView animateWithDuration:2 animations:^{
        [self setAlpha:0];
    } completion:completion];
}

@end

So, you only have to import the new file to your class or inside your Prefix.pch and use it like this:

[_label fadeOutWithCompletion:^(BOOL finished) {
   [_label fadeInWithCompletion:nil];
}];

Note that you could also use nil as the completion parameter when you have nothing else to do after completion.

I also recommend you do not parameterize the duration to keep a pattern through you entire application.

This implementation can be used in the future for UIButton, UILabel, UITextField... Well, any class derived from UIView.