CODEWITHSUNDEEP
iphoneioscaanimationcatextlayercatransaction
Kevin_TA
Kevin_TA

Reputation: 4675

CATransaction CompletionBlock Firing Immediately

I have this piece of code that works perfectly in one of my other projects where I am achieving a 'strobe' effect of text flashing from black to white on a loop. When I copied and pasted it into another one of my projects, the CompletionBlock fires immediately, ignoring the animation duration. What could be the reason?

- (void)animateTextFlashingWhite
{
    [CATransaction begin];
    [CATransaction setCompletionBlock:^{
        [self animateTextFlashingBlack];
        NSLog(@"finished white");
    }];
    [CATransaction setValue:[NSNumber numberWithFloat:0.7f] forKey:kCATransactionAnimationDuration];
    self.myStrobeLabel.textColor = [UIColor whiteColor];
    [CATransaction commit];
}

- (void)animateTextFlashingBlack
{
    [CATransaction begin];
    [CATransaction setCompletionBlock:^{
        [self animateTextFlashingWhite];
        NSLog(@"finished black");
    }];
    [CATransaction setValue:[NSNumber numberWithFloat:0.7f] forKey:kCATransactionAnimationDuration];
    self.myStrobeLabel.textColor = [UIColor blackColor];
    [CATransaction commit];
}

Upvotes: 1

Views: 1441

Answers (1)

Lily Ballard
Lily Ballard

Reputation: 185663

I don't think textColor is animatable.

If you simply want a crossfade, you can accomplish this by adding a CATransition object to the label.

[self.myStrobeLabel.layer addAnimation:[CATransition animation] forkey:@"transition"];
self.myStrobeLabel.textColor = [UIColor blackColor];

Upvotes: 2

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