UinavigationBar change la couleur de teinte avec animation

Question

est-il possible de changer la teinte avec une animation pour un effet plus lisse?

Cela ne fonctionne pas pour moi:

[UIView beginAnimations:nil context:nil];
[self.navigationController.navigationBar setTintColor:[UIColor greenColor]];
[UIView commitAnimations];

Je ne suis pas sûr s'il est même possible d'utiliser des composants de pomme natifs, car je suppose qu'ils utiliseront CG pour générer le dégradé ... veulent simplement savoir avant que je commence à construire ma propre solution ...

Cheers Murs :)

Answer 1

You wouldn't believe the length I went through to actually make that possible; it annoyed me to no end that this isn't a stock iOS feature and that transition of tintColor look ugly while the animation to push/pop a viewController is so smooth.

There'a lot of code that checks when to fade, and I've even written a class called PSPDFNavigationAppearanceSnapshot to preserve the navigation state when being popped. (I got that idea from the awesome NimbusKit)

The actual animation is pretty easy:

[self.navigationController.navigationBar.layer addAnimation:PSPDFFadeTransition() forKey:nil];

CATransition *PSPDFFadeTransition(void) {
    return PSPDFFadeTransitionWithDuration(0.25f);
}

CATransition *PSPDFFadeTransitionWithDuration(CGFloat duration) {
    CATransition *transition = [CATransition animation];
    transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    transition.type = kCATransitionFade;
    transition.duration = duration;
    return transition;
}

You can compact that code even more; it's a snipped from my iOS PDF library PSPDFKit and I use the fade in various places, thus the helper functions.

Answer 2

You can't animate bar tint - the list of properties (for a UIView) that can be animated in this way is here.

I don't think you can do that at all unless you want to overlay a bar that has a neutral tint with a UIView whose background color is changing. backgroundColor is one of the properties that can be animated. But you may have to get sneaky if you want to put a UIView on top of the navigation bar, I don't know of a way to do that.

Another thought - subclassing and doing the drawing yourself in drawRect?

Answer 3

We find the solution in another thread : Transition Color navBar

The solution was animating the attribut barTinTColor. Here is the code :

 self.navigationController.navigationBar.barTintColor = [UIColor redColor];
 [UIView animateWithDuration:5.0f animations:^{
    self.navigationController.navigationBar.barTintColor = [UIColor blueColor];
} completion:^(BOOL finished) {
}];