UINavigationBar.appearance().tintColor does not work in Swift

Question

Created Sep ’15

Replies 7

Boosts 0

Views 9.3k

Participants 3

I ported a file from Objective_c to Swift that among its configurations changed the tabbar color: the code I used in objective-c was:

UIColor* barColor=[UIColor colorWithRed:.88 green:.05 blue:.05 alpha:1];
if([self.navigationController.navigationBar respondsToSelector:@selector(barTintColor)])
{
    /
    self.navigationController.navigationBar.barTintColor = barColor;
}
else
{
    [[UINavigationBar appearance] setTintColor:barColor];
    /
    /
}
[super viewWillAppear:animated];

and the corresponding Swift code is:

let barColor = UIColor(red:0.88, green:0.05, blue:0.05, alpha:1)
if UIDevice.currentDevice().systemVersion.compare("8.0", options: .NumericSearch) == .OrderedDescending
    {
        /
     UINavigationBar.appearance().tintColor=barColor
     /
    }
    else
    {
        self.navigationController!.navigationBar.barTintColor = barColor;
    }

Yet, while the objective-c code did change the tab-bar color, the corresponding swift code leaves it unscathed, at least on the simulator.

What is even more puzzling is that I have a sister ViewController in which I use:

self.navigationController!.navigationBar.barTintColor = barColor

even on iOS 9 without any crash altogether and its execution actually changes the color of the tabbar.

If I use that piece of code in the original viewcontroller on iOS 9 I have a crash instead, and the alternative code has no effect.

Boost

Answer 1

OOPer OP

Sep ’15

Your Swift code is not corresponding to your Objective-C code. If you want them match, you can write something like this:

        if self.navigationController!.navigationBar.respondsToSelector("barTintColor") {
            self.navigationController!.navigationBar.barTintColor = barColor
        } else {
            UINavigationBar.appearance().tintColor=barColor
        }

Your version checking code `UIDevice.currentDevice().systemVersion.compare("8.0", options: .NumericSearch) == .OrderedDescending` returns true when systemVersion > 8.0, which may not be what you want. So, in iOS 9 the line `UINavigationBar.appearance().tintColor=barColor` is executed, which may very probably the cause of the crash.

In Swift 2, you use `#available` for version checking, but as far as I can find in the documentations, you have no need for availability checking to use `barTintColor`.

Swift is only available for targets iOS 7 or later, and the property barTintColor got available in iOS 7.

So, remove the whole if-else and replace it with:

        self.navigationController!.navigationBar.barTintColor = barColor

You say this code works in the sister ViewController, I believe the same code works in other ViewControllers.

0

Answer 2

fbartolom OP

Sep ’15

I first tried it but it did not work: I do not remember if it crashed or always returned the same value. I shall test again and let you know when I am back at my mac.The problem about:

self.navigationController!.navigationBar.barTintColor = barColor

is that it crashed the app on iOS 9, on that specific viewController. As I said it works fine on another. I will also try this again and let you know,

0

Answer 3

jsslai OP

Sep ’15

It will crash if your view controller is not in UINavigationController's navigation stack. Then navigationController property is nil and accessing implicitly unwrapped optional crashes the app.

0

Answer 4

OOPer OP

Sep ’15

Thanks, jsslai. I should have noticed the possibility.

So, it seems I need to make one thing clear:

[[UINavigationBar appearance] setTintColor:barColor]; does not work in Objective-C neither, since iOS 7.

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Answer 5

fbartolom OP

Sep ’15

In fact the navigation controller was nil, if I put the conditional instead of the forced unwrapping I have no crash. Yet I do not undersand why the navigation controller is nil. I execute che code in the ViewWillAppear, is it too early to get an handle to the navigationController? The corresponding scene is the first scene of a tabBarController itself reachable from a scene which is the root scene of a custom navigation controller.

0

Answer 6

jsslai OP

Sep ’15

Is your view controller's parent a navigation controller? If yes the view controller's navigationController property should be set when viewWillAppear is called.

0

Answer 7

fbartolom OP

Sep ’15

Grandfather. As a matter of fact since a few tests the navigationcontroller was found and the color correctly assigned. I think this is a bug in the simulator or iOS 9 by which at viewWillAppear time the navigation controller accessibility is shaky. At any rate by setting a conditional instead of a forced unwrapping I may avert the crash and at worst have a navigation bar of the wrong color. Finally I confim:

self.navigationController?.navigationBar.barTintColor = barColor

works even on iOS 9, as you suggested.

0