如何在iOS 13中更改状态栏Alpha？

Question

I want to change the Status Bar Alpha in iOS 13.

let statusBarWindow = UIApplication.shared.value(forKey: "statusBarWindow") as? UIWindow
statusBarWindow?.alpha = 0.5

When I try this, the app crashes (Thread 1: signal SIGABRT).

Answer 1

The status bar is rendered by a system process (out of the app process) on iOS 13 so there is no way for an app to change this. (Source: speaking to UIKit engineers at the WWDC 2019 labs.)

You can see this in the Apple Books app, which used to dim the status bar in its dark mode on iOS 12, but this does not happen on iOS 13.

Answer 2

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'App called -statusBar or -statusBarWindow on UIApplication: this code must be changed as there's no longer a status bar or status bar window. Use the statusBarManager object on the window scene instead.'

You can refer to the following answer to resolve your crash.

var statusBarUIView: UIView? {
        if #available(iOS 13.0, *) {
            let tag = 38482458
            if let statusBar = self.keyWindow?.viewWithTag(tag) {
                return statusBar
            } else {
                let statusBarView = UIView(frame: UIApplication.shared.statusBarFrame)
                statusBarView.tag = tag

                self.keyWindow?.addSubview(statusBarView)
                return statusBarView
            }
        } else {
            if responds(to: Selector(("statusBar"))) {
                return value(forKey: "statusBar") as? UIView
            }
        }
        return nil
    }

These mentioned solutions worked for me.

Answer 3

I have a custom solution for changing status bar on iOS 13 and below. Here is how to do that:

if #available(iOS 13.0, *) {
   let app = UIApplication.shared
   let statusBarHeight: CGFloat = app.statusBarFrame.size.height

   let statusbarView = UIView()
   statusbarView.backgroundColor = UIColor.red
   view.addSubview(statusbarView)

   statusbarView.translatesAutoresizingMaskIntoConstraints = false
   statusbarView.heightAnchor
     .constraint(equalToConstant: statusBarHeight).isActive = true
   statusbarView.widthAnchor
     .constraint(equalTo: view.widthAnchor, multiplier: 1.0).isActive = true
   statusbarView.topAnchor
     .constraint(equalTo: view.topAnchor).isActive = true
   statusbarView.centerXAnchor
     .constraint(equalTo: view.centerXAnchor).isActive = true

} else {
      let statusBar = UIApplication.shared.value(forKeyPath: 
   "statusBarWindow.statusBar") as? UIView
      statusBar?.backgroundColor = UIColor.red
}

Gist

Also, check the article iOS 13 How to Change StatusBar Color?

One last thing, you can still change statusbar style with :

 override var preferredStatusBarStyle : UIStatusBarStyle {
    return UIStatusBarStyle.lightContent
    //return UIStatusBarStyle.default   // Make dark again
}