可选类型'Bool'不能用作布尔值；测试'！= nil'代替 [英] optional type 'Bool' cannot be used as a boolean; Test for '!=nil' instead

问题描述

可选类型'Bool'不能用作布尔值；测试'！= nil'代替

optional type 'Bool' cannot be used as a boolean; Test for '!=nil' instead

我第一次出现 if 时出错，方法是替换if条件(after)，而 second if condition 从未运行.任何的想法?

I got an error at first if, by replacing the if condition (after), the second if condition did never run. Any idea?

if(userEmail?.isEmpty || userPassword?.isEmpty || userRepeatPassword?.isEmpty){
      displayMyAlertMessage("All fields are required")
      return
}

if(userPassword != userRepeatPassword){
      displayMyAlertMessage("Passwords do not match.")
}

之后:

if(userEmail != nil || userPassword != nil || userRepeatPassword != nil){
      displayMyAlertMessage("All fields are required")
      return
}

if(userPassword != userRepeatPassword){
      displayMyAlertMessage("Passwords do not match.")
}

推荐答案

您正在检查您的注释是否与nil值不同，然后返回是否与nil不同，如果您想检查它是否为nil，则根据第二个注释

You are checking if the value is different of nil and returning if it is, based un your comments and your second if you probably want to check if it is nil.

println("Checking login details")
if(userEmail.isEmpty || userPassword.isEmpty || userRepeatPassword.isEmpty){
      displayMyAlertMessage("All fields are required")
      println("Fail to login not all fields where fill") 
      return
} else if(userPassword != userRepeatPassword){
      displayMyAlertMessage("Passwords do not match.")
      println("Fail to login password does not match") 
} else {  
  var uiAlert = UIAlertController(title: "Alert", message: "Registration was successful", preferredStyle: UIAlertControllerStyle.Alert)
  self.presentViewController(uiAlert, animated: true, completion: nil)
  uiAlert.addAction(UIAlertAction(title: "Ok", style: .Default, handler: { action in
   dismissViewControllerAnimated(true, completion:nil)
  }))
}

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