Status bar won’t disappear

Try this:

[[UIApplication sharedApplication] setStatusBarHidden:NO withAnimation:UIStatusBarAnimationFade];

From Apple Class Reference:

setStatusBarHidden:withAnimation:

Hides or shows the status bar, optionally animating the transition. - (void)setStatusBarHidden:(BOOL)hidden withAnimation:(UIStatusBarAnimation)animation Parameters

hidden YES to hide the status bar, NO to show the status bar.

animation A constant that indicates whether there should be an animation and, if one is requested, whether it should fade the status bar in or out or whether it should slide the status bar in or out.

1. Set the UIViewControllerBasedStatusBarAppearance to YES in the .plist file.

2. In the viewDidLoad do a [self setNeedsStatusBarAppearanceUpdate];

3. Add the following method:

   - (UIStatusBarStyle)preferredStatusBarStyle
   { 
       return UIStatusBarStyleLightContent; 
   }
   

Note: This does not work for controllers inside UINavigationController, please see Tyson's comment below :)

Swift 3 - This will work controllers inside UINavigationController. Add this code inside your controller.

// Preferred status bar style lightContent to use on dark background.
// Swift 3
override var preferredStatusBarStyle: UIStatusBarStyle {
    return .lightContent
}

Swift 5 and SwiftUI

For SwiftUI create a new swift file called HostingController.swift

import Foundation
import UIKit
import SwiftUI

class HostingController: UIHostingController<ContentView> {
    override var preferredStatusBarStyle: UIStatusBarStyle {
        return .lightContent
    }
}

Then change the following lines of code in the SceneDelegate.swift

window.rootViewController = UIHostingController(rootView: ContentView())

to

window.rootViewController = HostingController(rootView: ContentView())