iPhone:覆盖 UIButton buttonWithType 以返回子类 [英] iPhone: Override UIButton buttonWithType to return subclass

问题描述

我希望能够创建一个具有超大响应区域的 UIButton.我知道这样做的一种方法是覆盖子类中的 hitTest 方法，但我如何首先实例化我的自定义按钮对象?

[OversizedButton buttonWithType: UIButtonTypeDetailDisclosure];

无法开箱即用，因为 buttonWithType 返回的是 UIButton，而不是 OversizedButton.

看来我也需要重写 buttonWithType 方法.有谁知道怎么做?

@implementation OversizedButton+ (id)buttonWithType:(UIButtonType)buttonType{//构造并返回一个 OversizedButton 而不是 UIButton//需要处理 UIButtonTypeDetailDisclosure 等特殊类型//我需要知道如何做这部分}- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event{//如果触摸事件在超大区域，则返回结果//我已经知道如何做这部分}@结尾

或者，也许我可以使用 alloc/initWithFrame 创建按钮.但是 buttonType 属性是只读的，那么如何创建自定义按钮类型呢?

注意:我知道还有其他方法可以做到这一点，例如在可见按钮后面设置一个不可见按钮.我不喜欢这种方法，宁愿避免它.对上述方法的任何帮助都会非常有帮助.谢谢

解决方案

UIButton buttonWithType: 返回 UIButton 或 UIRoundedRectButton，具体取决于type 参数的值.

由于 UIButton 没有提供 initWithType: 方法，我认为尝试重写 buttonWithType: 会很危险.p>

我建议您改为子类 UIControl.然后，您可以将按钮作为子视图添加到您的控件，并拦截 hitTest:withEvent:.

I want to be able to create a UIButton with an oversized responsive area. I know that one way to do that is to override the hitTest method in a subclass, but how do I instantiate my custom button object in the first place?

[OversizedButton buttonWithType: UIButtonTypeDetailDisclosure];

doesn't work out of the box because buttonWithType returns a UIButton, not an OversizedButton.

So it seems like I need to override the buttonWithType method as well. Does anyone know how to do this?

@implementation OversizedButton

+ (id)buttonWithType:(UIButtonType)buttonType
{
   // Construct and return an OversizedButton rather than a UIButton
   // Needs to handle special types such as UIButtonTypeDetailDisclosure
   // I NEED TO KNOW HOW TO DO THIS PART
}

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event 
{
   // Return results if touch event was in oversized region
   // I ALREADY KNOW HOW TO DO THIS PART
}

@end

Alternatively, maybe I could create the button using alloc/initWithFrame. But the buttonType property is readonly, so how do you create the custom button types?

Note: I know there are other ways to do this, such as having an invisible button behind the visible one. I don't care for that approach and would prefer to avoid it. Any help on the approach described above would be very helpful. Thanks

解决方案

UIButton buttonWithType: returns a UIButton or a UIRoundedRectButton, depending on the value of the type parameter.

As UIButton doesn't provide an initWithType: method, I believe it would be dangerous to try and override buttonWithType:.

I suggest you subclass UIControl instead. You can then add a button as a subview to your control, and intercept hitTest:withEvent:.

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