在突出显示时更改 UIButton 边框颜色

Question

我有一个简单的自定义 UIButton，我添加了：

button.layer.bordercolor = [[UIColor blueColor]CGColor];

但是，我想在按钮突出显示时更改 .bordercolor。我尝试向按钮的 touchDown 动作添加一个动作，将 .bordercolor 更改为红色，但是当用户抬起手指时，它会保持红色而不是返回蓝色。有什么想法吗？

Answer 1

你走在正确的轨道上。检查下面的代码，它对此进行了详细说明，但是您要做的是将选择器链接到按钮上的不同控件事件。一个用于touchDown 将阴影更改为红色，另一个用于touchUpInside 在您抬起手指时将阴影变回。

此外，我看到您在 Stack Overflow 上提出了几个问题，但尚未将任何问题标记为正确答案。要继续在此网站上获得帮助，您需要开始标记问题的正确答案。

[myButton addTarget:self action:@selector(highlightBorder) forControlEvents:UIControlEventTouchDown];
[myButton addTarget:self action:@selector(unhighlightBorder) forControlEvents:UIControlEventTouchUpInside];


- (void)highlightBorder
{
    myButton.layer.borderColor = [[UIColor redColor]CGColor];
}

- (void)unhighlightBorder
{
    myButton.layer.borderColor = [[UIColor blueColor]CGColor];
    //additional code for an action when the button is released can go here.
}

注意： Other options for UIControlEvents 包括：

enum {
   UIControlEventTouchDown           = 1 <<  0,
   UIControlEventTouchDownRepeat     = 1 <<  1,
   UIControlEventTouchDragInside     = 1 <<  2,
   UIControlEventTouchDragOutside    = 1 <<  3,
   UIControlEventTouchDragEnter      = 1 <<  4,
   UIControlEventTouchDragExit       = 1 <<  5,
   UIControlEventTouchUpInside       = 1 <<  6,
   UIControlEventTouchUpOutside      = 1 <<  7,
   UIControlEventTouchCancel         = 1 <<  8,

   UIControlEventValueChanged        = 1 << 12,

   UIControlEventEditingDidBegin     = 1 << 16,
   UIControlEventEditingChanged      = 1 << 17,
   UIControlEventEditingDidEnd       = 1 << 18,
   UIControlEventEditingDidEndOnExit = 1 << 19,

   UIControlEventAllTouchEvents      = 0x00000FFF,
   UIControlEventAllEditingEvents    = 0x000F0000,
   UIControlEventApplicationReserved = 0x0F000000,
   UIControlEventSystemReserved      = 0xF0000000,
   UIControlEventAllEvents           = 0xFFFFFFFF
};

Answer 2

SWIFT 2.x 解决您的问题：

➜ 只需使用“didSet”观察者覆盖突出显示的属性。

override var highlighted: Bool {
    didSet {

        switch highlighted {
        case true:
            layer.borderColor = UIColor.lightGrayColor().CGColor
        case false:
            layer.borderColor = UIColor.blackColor().CGColor
        }
    }
}

斯威夫特 3：

override var isHighlighted: Bool {
    didSet {

        switch isHighlighted {
        case true:
            layer.borderColor = UIColor.lightGray.cgColor
        case false:
            layer.borderColor = UIColor.black.cgColor
        }
    }
}

Answer 3

您可以覆盖 UIButton 子类中的 setHighlighted 和 setSelected 方法。从那里您只需调整边框颜色，如下所示：

- (void)setHighlighted:(BOOL)highlighted {

    [super setHighlighted:highlighted];

    [self tweakState:highlighted];
}

- (void)setSelected:(BOOL)selected {

    [super setSelected:selected];

    [self tweakState:selected];
}

- (void)tweakState:(BOOL)state {

    if (state) {
        self.layer.borderColor = [_highlightedBorderColor CGColor];
    }
    else {
        self.layer.borderColor = [_defaultBorderColor CGColor];
    }
}

Answer 4

斯威夫特 4：

override var isHighlighted: Bool {
    didSet {
        layer.borderColor = isHighlighted ? UIColor.lightGray.cgColor : UIColor.black.cgColor
    }
}

Answer 5

独立解决方案：

static UIColor *BorderColor()
{
  return [UIColor grayColor];
}

static UIColor *HighlightedBorderColor()
{
  return [UIColor lightGrayColor];
}

@interface BorderedButton : UIButton

@end

@implementation BorderedButton

- (instancetype)initWithFrame:(CGRect)frame
{
  self = [super initWithFrame:frame];
  if (self) {
    self.layer.borderColor = BorderColor().CGColor;
    self.layer.cornerRadius = 4.0;
    self.layer.borderWidth = 1.0;
  }
  return self;
}

- (void)setHighlighted:(BOOL)highlighted
{
  [super setHighlighted:highlighted];
  self.layer.borderColor = (highlighted) ? HighlightedBorderColor().CGColor : BorderColor().CGColor;
}

@end

感谢@josip-b！

Answer 6

对于不涉及子类化的解决方案，您始终可以向 UIButton 添加扩展方法。例如

func setBackgroundColor(_ backgroundColor: UIColor,
                        borderColor: UIColor,
                        borderWidth: CGFloat,
                        cornerRadius: CGFloat,
                        forState state: UIControlState) {

    UIGraphicsBeginImageContext(bounds.size)
    guard let context = UIGraphicsGetCurrentContext() else { return }

    if borderWidth > 0 {
        layer.borderWidth = 0 // hide the layer's border if we're going to draw a border
    }

    context.addPath(UIBezierPath(roundedRect: bounds.insetBy(dx: borderWidth, dy: borderWidth), cornerRadius: cornerRadius).cgPath)
    context.setStrokeColor(borderColor.cgColor)
    context.setFillColor(backgroundColor.cgColor)
    context.setLineWidth(borderWidth)

    context.closePath()
    context.strokePath()
    context.fillPath()

    let buttonImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    setBackgroundImage(buttonImage, for: state)
}