如何从superview获取所有元素（如：UiLabel，UITextfield）并设置标签文本颜色和文本字段占位符颜色

Question

我在设置UITextfield占位符颜色和UIlabel文本颜色时遇到问题

1. 我们可以在给定的屏幕中看到我需要的东西。

  

以下是我用来识别UILabel和UITextfield的代码。

func processSubviewsNight(of view: UIView) {

        for subview in view.subviews {

            if subview is UITextField {
                if let textField : UITextField = subview as? UITextField {
                    textField.setValue(UIColor.white, forKeyPath: "_placeholderLabel.textColor")
                      textField.backgroundColor = UIColor.appBlueColor()
                }
            }

            if subview is UILabel {
                if let label : UILabel = subview as? UILabel {
                    label.textColor = UIColor.white
                }
            }

            if subview is UIButton {
                if let button : UIButton = subview as? UIButton {
                    button.backgroundColor = UIColor.red
                }
            }
                  processSubviewsNight(of: subview)
           }
    }

1. 问题是UITextfield占位符和UIButton文本进入UILabel循环并更改UITextfield占位符颜色与UIlabel文本颜色相同

Answer 1

您需要浏览所有子视图并检查相应的类型以更改其属性。

for subview in view.subviews {

        if let textField = subview as? UITextFiled {

            textFiled.setValue(UIColor.white, forKeyPath: "_placeholderLabel.textColor")
            textField.backgroundColor = UIColor.appBlueColor()
            //set properties

        } else if let button = subview as? UIButton {

            button.backgroundColor = UIColor.red
            //set properties

        } else if let label = subview as? UILabel {

            label.textColor = UIColor.white
            //set properties
        }
    }

Answer 2

您应该在其他情况下调用processSubviewsNight(of: subview)。否则，textfield的子视图将传递给此方法。

func processSubviewsNight(of view: UIView) {

        for view in self.view.subviews {
            if let lbl = view as? UILabel {
                label.textColor = UIColor.white
            } else if let textField = view as? UITextField {
                textField.setValue(UIColor.white, forKeyPath: "_placeholderLabel.textColor")
                textField.backgroundColor = UIColor.appBlueColor()
            } else if let button = view as? UIButton {
                button.backgroundColor = UIColor.red
            } else{
                processSubviewsNight(of: view)
            }
        }

    }