向观察者添加完成时应用崩溃

Question

>我正在尝试向通知观察器添加一个块，但是在移动前景和背景时应用程序崩溃了。如果我添加方法来观察它的工作正常，只有在阻塞它崩溃的情况下。这是我正在尝试的代码。

class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()

NotificationCenter.default.addObserver(self, selector: #selector(foregroundEntered(closure:)), name: UIApplication.willEnterForegroundNotification, object: nil)
// Do any additional setup after loading the view.
}

@objc func foregroundEntered(closure: () -> Void) {
/// do some stuff
}

override func viewDidDisappear(_ animated: Bool) {
super.viewDidDisappear(animated)
NotificationCenter.default.removeObserver(self, name: UIApplication.willEnterForegroundNotification, object: nil)
}
}

提前谢谢。

Answer 1

替换

@objc func foregroundEntered(closure: () -> Void) { 

跟

@objc func foregroundEntered(_ notif: NSNotification) {

并改变

NotificationCenter.default.addObserver(self, selector: #selector(foregroundEntered), name: UIApplication.willEnterForegroundNotification, object: nil)