I am creating an app that has the screen switch rapidly between black and white. For this I am using a Timer,
我正在创建一个在黑白之间快速切换屏幕的应用程序。为此，我使用的是计时器，
My problem boils down to not being able to call a function from the same scope (changeBackgroundColor) in timer's declaration.
我的问题归结为无法在timer的声明中调用同一范围（changeBackgroundColor）中的函数。
let timer = Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true, block: changeBackgroundColor)
//Error: 'Cannot convert value of type '(ViewController) -> (Timer) -> Void' to expected argument type '(Timer) -> Void'
func changeBackgroundColor(timer: Timer) -> Void {
//change the color of the screen (not the issue here)
}
I thought I had understood closures but there seems to be a problem with the scopes here.
我以为我已经理解了闭包，但这里的示波器似乎存在问题。
1 个解决方案
#1
1
The whole point of using the "block" version of a timer is to avoid having to create a separate function.
使用计时器的“块”版本的全部意义在于避免必须创建单独的功能。
You should write it as follows:
你应该写如下：
let timer = Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true) { (timer) in
// change the color of the screen
}
#1
1
The whole point of using the "block" version of a timer is to avoid having to create a separate function.
使用计时器的“块”版本的全部意义在于避免必须创建单独的功能。
You should write it as follows:
你应该写如下：
let timer = Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true) { (timer) in
// change the color of the screen
}