如何每隔(x)秒从数组中获取随机字符串(SWIFT 3)(SPRITEKIT)

let stringArray = ["String1", "String2", "String3", "String4"]

let timer = Timer.scheduledTimer(timeInterval: x, target: self, selector: #selector(getRandomString), userInfo: nil, repeats: true)

@objc func getRandomString() {
    let randomIndex = Int(arc4random_uniform(UInt32(stringArray.count)))
    let randomString = stringArray[randomIndex]
    
    // 在这里进行随机字符串的处理
    // ...
}