我声明一个变量,然后尝试在UIAlertAction中设置它的值。当我点击"我要去那里" 按钮在我的下面的代码中,输出是:
1 thisCustomerRequesting:true
3 thisCustomerRequesting:false
你能告诉我为什么行" 2 thisCustomerRequesting:...." 在输出中缺失,为什么" 3 thisCustomerRequesting:false&#34 ; 是假的,而我希望它是真的。
var thisCustomerRequesting = false
if thisCustomerRequesting == false {
let alert = UIAlertController(title: "title", message: "message", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "I am going there", style: .destructive, handler: {
(alertAction1: UIAlertAction) in
thisCustomerRequesting = true
print("1 thisCustomerRequesting: \(thisCustomerRequesting)")
}))
alert.addAction(UIAlertAction(title: "Close", style: .default,handler: nil))
self.present(alert, animated: true, completion: nil)
print("2 thisCustomerRequesting: \(thisCustomerRequesting)")
}
print("3 thisCustomerRequesting: \(thisCustomerRequesting)")
答案 0 :(得分:1)
输出2应位于您的控制台中,但应高于1 thisCustomerRequesting: true
。
输出3显示3 thisCustomerRequesting: false
,因为thisCustomerRequesting
在用户按下按钮时异步设置为true
。
那时print("3 thisCustomerRequesting: \(thisCustomerRequesting)")
已经执行。