如何在Swift中扩展特定UIButton的点击区域？

Question

在我的应用程序中，我有一个很小的UIButton ，所以我考虑增加它的点击区域。

我找到了一个扩展名：

fileprivate let minimumHitArea = CGSize(width: 100, height: 100)

extension UIButton {
    open override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        // if the button is hidden/disabled/transparent it can't be hit
        if self.isHidden || !self.isUserInteractionEnabled || self.alpha < 0.01 { return nil }

        // increase the hit frame to be at least as big as `minimumHitArea`
        let buttonSize = self.bounds.size
        let widthToAdd = max(minimumHitArea.width - buttonSize.width, 0)
        let heightToAdd = max(minimumHitArea.height - buttonSize.height, 0)
        let largerFrame = self.bounds.insetBy(dx: -widthToAdd / 2, dy: -heightToAdd / 2)

        // perform hit test on larger frame
        return (largerFrame.contains(point)) ? self : nil
    }
}

但是当我使用它时，我应用程序中的每个按钮都有较大的点击区域。 我想将其增加到仅一个specialButton我该怎么做？

Answer 1

您可以在扩展程序中添加一个computed property ，如果要启用点击区域，可以在控制器中进行设置：

fileprivate let minimumHitArea = CGSize(width: 100, height: 100)

extension UIButton {

  var isIncreasedHitAreaEnabled: Bool {
    get {
      // default value is false, so you can easily handle from outside when to enable the increased hit area of your specific button
      return false
    }
    set {

    }
  }

  open override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
    // if the button is hidden/disabled/transparent it can't be hit
    if self.isHidden || !self.isUserInteractionEnabled || self.alpha < 0.01 { return nil }

    // only if it's true the hit area can be increased
    if isIncreasedHitAreaEnabled {
      // increase the hit frame to be at least as big as `minimumHitArea`
      let buttonSize = self.bounds.size
      let widthToAdd = max(minimumHitArea.width - buttonSize.width, 0)
      let heightToAdd = max(minimumHitArea.height - buttonSize.height, 0)
      let largerFrame = self.bounds.insetBy(dx: -widthToAdd / 2, dy: -heightToAdd / 2)

      // perform hit test on larger frame
      return (largerFrame.contains(point)) ? self : nil
    }
    return self
  }
}

然后，如果要为特定按钮（例如，在viewDidLoad ）增加它，则在视图控制器中只需将isIncreasedHitAreaEnabled设置为true即可：

override func viewDidLoad() {
  super.viewDidLoad()
  specialButton.isIncreasedHitAreaEnabled = true
}

更新：

首先，您使用的方法无法正常工作。 而且，我对computed property也不像我想的那样有效。 因此，即使该方法无法按预期工作，我也只想使用computed property来更新我的方法。 因此，要从外部设置属性，可以使用关联对象 。 也可以看看这里 。 现在，通过此解决方案，可以从您的控制器处理Bool属性isIncreasedHitAreaEnabled ：

fileprivate let minimumHitArea = CGSize(width: 100, height: 100)
private var xoAssociationKey: UInt8 = 0

extension UIButton {

  var isIncreasedHitAreaEnabled: Bool {
    get {
      return (objc_getAssociatedObject(self, &xoAssociationKey) != nil)
    }
    set(newValue) {
      objc_setAssociatedObject(self, &xoAssociationKey, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN)
    }
  }

  open override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
    // if the button is hidden/disabled/transparent it can't be hit
    if self.isHidden || !self.isUserInteractionEnabled || self.alpha < 0.01 { return nil }

    if isIncreasedHitAreaEnabled {
      // increase the hit frame to be at least as big as `minimumHitArea`
      let buttonSize = self.bounds.size
      let widthToAdd = max(minimumHitArea.width - buttonSize.width, 0)
      let heightToAdd = max(minimumHitArea.height - buttonSize.height, 0)
      let largerFrame = self.bounds.insetBy(dx: -widthToAdd / 2, dy: -heightToAdd / 2)

      // perform hit test on larger frame
      return (largerFrame.contains(point)) ? self : nil
    }
    return self
  }
}

Answer 2

不要扩大打击范围； 缩小绘图区域。 使按钮成为UIButton的子类，并在该子类中实现rect方法，方法如下：

class MyButton : UIButton {
    override func contentRect(forBounds bounds: CGRect) -> CGRect {
        return bounds.insetBy(dx: 30, dy: 30)
    }
    override func backgroundRect(forBounds bounds: CGRect) -> CGRect {
        return bounds.insetBy(dx: 30, dy: 30)
    }
}

现在，该按钮在其可见背景之外可以点击30点。

Answer 3

创建一个自定义UIButton类，并覆盖pointInside：（CGPoint）point方法，如下所示。 然后从viewController设置这些属性值。

#import <UIKit/UIKit.h>
@interface CustomButton : UIButton
    @property (nonatomic) CGFloat leftArea;
    @property (nonatomic) CGFloat rightArea;
@property (nonatomic) CGFloat topArea;
@property (nonatomic) CGFloat bottomArea;
@end




#import "CustomButton.h
@implementation CustomButton

-(BOOL) pointInside:(CGPoint)point withEvent:(UIEvent *)event
{
    CGRect newArea = CGRectMake(self.bounds.origin.x - _leftArea, self.bounds.origin.y - _topArea, self.bounds.size.width + _leftArea + _rightArea, self.bounds.size.height + _bottomArea + _topArea);

    return CGRectContainsPoint(newArea, point);
}
@end