ios - Swift isKindOfClass 不起作用

Question

我有一个 ViewController 和一些供用户输入的标签和文本字段，在某些时候我需要遍历所有文本字段以收集用户的输入。

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    self.configureView()
   for views in self.view.subviews        {
        if view is UITextField
        {
            println("inside")
        }
        println(views.description)

    }
}

对于此代码，“内部”永远不会打印出来。但是我确实看到了一些views.description的信息

   <UILabel: 0x7fa4b1c7bd00; frame = (16 97; 76 21); text = 'FromDate';        opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer =           <_UILabelLayer: 0x7fa4b1c44580>>
  <UILabel: 0x7fa4b1c9fd60; frame = (16 169; 82 21); text = 'ControlNO'; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer = <_UILabelLayer: 0x7fa4b1c77fb0>>

>

   <UITextField: 0x7fa4b1c7a050; frame = (106 95; 197 30); text = ''; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; layer = <CALayer: 0x7fa4b1c6c800>>

  <UITextField: 0x7fa4b1c9c060; frame = (106 126; 197 30); text = ''; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; tag = 1; layer = <CALayer: 0x7fa4b1c9c2c0>>

   <_UILayoutGuide: 0x7fa4b1d11d20; frame = (0 0; 0 0); hidden = YES; layer = <CALayer: 0x7fa4b1d11e00>>
   <_UILayoutGuide: 0x7fa4b1d253f0; frame = (0 0; 0 0); hidden = YES; layer = <CALayer: 0x7fa4b1d12f60>>

但是如果我 println(views.dynamicType) 我只能看到 ExistentialMetatype。

我的代码有什么问题？

Answer 1

循环变量叫做views，但是你测试view(这是不是循环变量，因此等同于 self.view):

for views in self.view.subviews { // "views" here
    if view is UITextField {      // "view" here
        println("inside")
    }
}

如果将循环变量重命名为view

for view in self.view.subviews {
    if view is UITextField {
        println("inside")
    }
}

然后一切都按预期工作。