自定义清除按钮

Question

我想在 UITextField 上创建自定义清除按钮，即使用 rightView 并将图像放在那里，问题是将原始清除按钮事件附加到该自定义 rightView。

在 Objective-C 中我可以这样做：

SEL clearButtonSelector = NSSelectorFromString(@"clearButton");
// Reference clearButton getter
IMP clearButtonImplementation = [self methodForSelector:clearButtonSelector];
// Create function pointer that returns UIButton from implementation of method that contains clearButtonSelector
UIButton * (* clearButtonFunctionPointer)(id, SEL) = (void *)clearButtonImplementation;
// Set clearTextFieldButton reference to “clearButton” from clearButtonSelector
UIButton *_clearTextFieldButton = clearButtonFunctionPointer(self, clearButtonSelector);
[_clearTextFieldButton setImage:[UIImage imageNamed:@"icon_remove"] forState:UIControlStateNormal];
self.hasClearButtonAsRightView = YES;

现在如何将其转换为 Swift？ 或任何解决方法的想法？

Answer 1

您可以像这样添加自定义按钮作为UITextField 的右视图

class CustomTextField : UITextField
{
    override init(frame: CGRect) {
        super.init(frame: frame)

        let clearButton = UIButton(frame: CGRect(origin: .zero, size: CGSize(width: 15, height: 15))
        clearButton.setImage(UIImage(named: "clear.png")!, forState: UIControlState.Normal)

        self.rightView = clearButton
        clearButton.addTarget(self, action: "clearClicked:", forControlEvents: .touchUpInside)

        self.clearButtonMode = .never
        self.rightViewMode = .always
    }

    func clearClicked(sender: UIButton)
    {
        self.text = ""
    }

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
}

Answer 2

按照其他答案中的建议实施自定义文本字段不是一个好主意。如果可能，您应该尝试使用扩展而不是继承，因为通过继承，您更有可能需要对代码库进行重大更改以响应更改，而使用扩展则可以更灵活地进行更改。

我强烈建议不要实现自定义文本字段，而是像这样扩展 UITextField 类：

extension UITextField {
    func applyCustomClearButton() {
        clearButtonMode = .Never
        rightViewMode   = .WhileEditing

        let clearButton = UIButton(frame: CGRectMake(0, 0, 16, 16))
        clearButton.setImage(UIImage(name: "iCFieldClear")!, forState: .Normal)
        clearButton.addTarget(self, action: "clearClicked:", forControlEvents: .TouchUpInside)

        rightView = clearButton
    }

    func clearClicked(sender:UIButton) {
        text = ""
    }
}

然后要使用它，您只需这样做：

yourTextField.applyCustomClearButton()

Answer 3

这是我在 Swift 3 中的解决方案。除了已经存在的答案之外，我还确保文本字段的左右视图（即搜索放大镜图像视图和自定义清除按钮）都有一个填充通过覆盖leftViewRect() 和rightViewRect() 向左/向右。否则，它们会粘在文本框的边缘。

class CustomTextField: UITextField
{
    fileprivate let searchImageLength: CGFloat = 22
    fileprivate let cancelButtonLength: CGFloat = 15
    fileprivate let padding: CGFloat = 8


    override init( frame: CGRect )
    {
        super.init( frame: frame )
        self.customLayout()
    }

    required init?( coder aDecoder: NSCoder )
    {
        super.init( coder: aDecoder )
        self.customLayout()
    }

    override func leftViewRect( forBounds bounds: CGRect ) -> CGRect
    {
        let x = self.padding
        let y = ( bounds.size.height - self.searchImageLength ) / 2
        let rightBounds = CGRect( x: x, y: y, width: self.searchImageLength, height: self.searchImageLength )
        return rightBounds
    }

    override func rightViewRect( forBounds bounds: CGRect ) -> CGRect
    {
        let x = bounds.size.width - self.cancelButtonLength - self.padding
        let y = ( bounds.size.height - self.cancelButtonLength ) / 2
        let rightBounds = CGRect( x: x, y: y, width: self.cancelButtonLength, height: self.cancelButtonLength )
        return rightBounds
    }

    fileprivate func customLayout()
    {
        // Add search icon on left side
        let searchImageView = UIImageView()
        searchImageView.contentMode = .scaleAspectFit
        let searchIcon = UIImage( named: "search_magnifier" )
        searchImageView.image = searchIcon
        self.leftView = searchImageView
        self.leftViewMode = .always

        // Set custom clear button on right side
        let clearButton = UIButton()
        clearButton.setImage( UIImage( named: "search_cancel" ), for: .normal )
        clearButton.contentMode = .scaleAspectFit
        clearButton.addTarget( self, action: #selector( self.clearClicked ), for: .touchUpInside )
        self.rightView = clearButton
        self.clearButtonMode = .never
        self.rightViewMode = .whileEditing
    }

    @objc fileprivate func clearClicked( sender: UIButton )
    {
        self.text = ""
    }
}

Answer 4

在 iOS 14 中，没有一个解决方案适合我。对于不同的设备尺寸，清除按钮的偏移量是错误的。 我有图像。如果没有，可以从 SF Symbols 下载。名字是 xmark.circle.fill 最后我用了这个

        let customClearButton = UIButton.appearance(whenContainedInInstancesOf: [UITextField.self])
        customClearButton.setImage(UIImage(named: "icon-x"), for: .normal)

Answer 5

更新到 Swift 5，基于 @marmoy answer：

public func addClearAllCustomButton() {
    clearButtonMode = .never
    rightViewMode = .whileEditing
    
    let clearButton = UIButton(frame: rightViewRect(forBounds: bounds))
    clearButton.setImage(UIImage(named: "clearAll"), for: .normal)
    clearButton.addTarget(self, action: #selector(didTouchClearAllButton(sender:)), for: .touchUpInside)

    rightView = clearButton
}

public func removeClearAllButton() {
    rightViewMode = .never
}

@objc func didTouchClearAllButton(sender: UIButton) {
    text = ""
}