如何在Swift中扩展特定UIButton的命中区域？

Question

在我的应用程序中，我有一个很小的UIButton，所以我想增加它的命中面积。

我发现的是，延伸：

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 
    } 
} 

但是当我用它，在我的应用程序的每个按钮都有一个更大的打击区域。我想将它增加到只有一个specialButton - 我该怎么做？

Answer 1

您可以将computed property添加到您的扩展，你可以在你的控制器设置，如果你想使灾区是这样的：

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 
    } 
} 

然后在您的视图控制器只需设置isIncreasedHitAreaEnabled到true如果你要增加它的特定按钮（例如，在您的viewDidLoad）：

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

更新：

首先您使用的方法不能像预期的那样工作。而且我的方法与computed property没有像我想象的那样工作。所以即使这种方法不能像预期的那样工作，我只想用computed property来更新我的方法。 因此，要从外部设置属性，您可以使用Associated Objects。也看看here。有了这个解决方案，现在有可能从你的控制器处理Bool财产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

不展开的点击区域;缩小绘图区域。使按钮的UIButton的子类，并且在子类中，实现rect方法，沿着这些线路：

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) 
    } 
} 

现在该按钮可点击30分的可见背景之外。

Answer 3

创建自定义的UIButton类和重写pointInside：（CGPoint）点法等的下方。然后从viewController中设置这些属性值。

#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