How to change PreferredStatusBarStyle programmatically - objective-c

Question

I'd like to change the color of status bar from white to black by press button, programmatically only in a single-ViewController
This is the code:
- (UIStatusBarStyle)preferredStatusBarStyle {
NSLog(#"PreferredStatusBarStyle");
if(nav_bar.alpha==1)
{
NSLog(#"->UIStatusBarStyleBlackOpaque");
return UIStatusBarStyleBlackOpaque;
}
else
{
NSLog(#"->UIStatusBarStyleLightContent");
return UIStatusBarStyleLightContent;
}}
then When I press a button action is:
[self setNeedsStatusBarAppearanceUpdate];
But this doesn't work!
When I press the button log write the correct status according to navbar.alpha, but statusbar text color remain UIStatusBarStyleBlackOpaque like when view appear.

Answer 1

setStatusBarStyle:animated: has been deprecated. In iOS9 you can achieve the same thing using preferredStatusBarStyle and setNeedsStatusBarAppearanceUpdate.
In your View Controller:
override func preferredStatusBarStyle() -> UIStatusBarStyle {
if (condition) {
return .LightContent
}
return .Default
}
And then when your condition changes:
self.setNeedsStatusBarAppearanceUpdate()

Answer 2

On Swift 4:
override var preferredStatusBarStyle: UIStatusBarStyle {
return .lightContent
}
Hope it helps anybody else to find this post.

Answer 3

what you need to do, is to call the -setStatusBarStyle:animated: method thru the shared application, like this
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent animated:YES];
you can use it without the animated parameter as well. keep in mind that UIStatusBarStyleBlackOpaque is deprecated in iOS 7, documentation says you wanna use UIStatusBarStyleLightContent instead
edit:
sorry, if u wanna use preferredStatusBarStyle, take a look at this preferredStatusBarStyle isn't called