iOS：如何讓我的UITextfield點擊時突出顯示？

Question

我是否必須用代碼來做到這一點，或者在檢查員中是否有某些東西缺失？

Answer 1

與UIButton不同，UITextField沒有突出顯示的狀態。如果你想改變文本字段的顏色，當它獲得焦點，您可以使用UITextFieldDelegate的

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField

當控件首次接收焦點。這將被調用。從那裏你可以改變背景和/或文字顏色。一旦焦點離開控制，您可以使用

- (BOOL)textFieldShouldEndEditing:(UITextField *)textField

來重置顏色。

Answer 2

在斯威夫特2，你可以使用委託功能，如下面，

class CustomTextField: UITextField, UITextFieldDelegate{ 
    init(){ 
     super.init(frame: CGRectMake(0, 0, 0, 0)) 
     self.delegate = self // SETTING DELEGATE TO SELF 
    } 

    func textFieldDidBeginEditing(textField: UITextField) { 
     textField.backgroundColor = UIColor.greenColor() // setting a highlight color 
    } 

    func textFieldDidEndEditing(textField: UITextField) { 
     textField.backgroundColor = UIColor.whiteColor() // setting a default color 
    } 
} 

Answer 3

如果您仍然希望能夠在您的ViewController使用其他委託功能，我建議你補充一點：

override weak var delegate: UITextFieldDelegate? { 
    didSet { 
     if delegate?.isKindOfClass(YourTextField) == false { 
      // Checks so YourTextField (self) doesn't set the textFieldDelegate when assigning self.delegate = self 
      textFieldDelegate = delegate 
      delegate = self 
     } 
    } 
} 

// This delegate will actually be your public delegate to the view controller which will be called in your overwritten functions 
private weak var textFieldDelegate: UITextFieldDelegate? 

class YourTextField: UITextField, UITextFieldDelegate { 

    init(){ 
     super.init(frame: CGRectZero) 
     self.delegate = self 
    } 

    func textFieldDidBeginEditing(textField: UITextField) { 
     textField.backgroundColor = UIColor.blackColor() 
     textFieldDelegate?.textFieldDidBeginEditing?(textField) 
    } 

    func textFieldDidEndEditing(textField: UITextField) { 
     textField.backgroundColor = UIColor.whiteColor() 
     textFieldDelegate?.textFieldDidBeginEditing?(textField) 
    } 
} 

這樣你的視圖控制器不需要知道你覆蓋了委託，你可以在你的視圖控制器中實現UITextFieldDelegate函數。

let yourTextField = YourTextField() 
yourTextField.delegate = self