我可以使用UIControlState的自定义值来控制自己吗？

Question

有没有办法为a设置自定义状态 - 不是现有UIControlState值之一UIControl？

在UIControlSate枚举中,有16位可用于自定义控件状态:

UIControlStateApplication  = 0x00FF0000,              // additional flags available for application use

问题是,UIControl的state属性是只读的.

我想为我UIButton的自定义状态设置不同的背景图像.

Answer 1

您可以在UIControl的子类中使用自定义状态.

• 创建一个名为的变量customState,您将在其中管理自定义状态.
• 如果需要设置状态,请对此变量执行标志操作,然后调用[self stateWasUpdated].
• 覆盖state属性以[super state]针对您的方式按位返回ORcustomState
• 重写enabled,selected并highlighted制定者,让他们打电话[self stateWasUpdated].这将允许您响应状态的任何更改,而不仅仅是更改customState
• stateWasUpdated用逻辑实现以响应状态的变化

在标题中:

#define kUIControlStateCustomState (1 << 16)

@interface MyControl : UIControl {
    UIControlState customState;
}

在实施中:

@implementation MyControl

-(void)setCustomState {
    customState |= kUIControlStateCustomState;
    [self stateWasUpdated];
}

-(void)unsetCustomState {
    customState &= ~kUIControlStateCustomState;
    [self stateWasUpdated];
}

- (UIControlState)state {
    return [super state] | customState;
}

- (void)setSelected:(BOOL)newSelected {
    [super setSelected:newSelected];
    [self stateWasUpdated];
}

- (void)setHighlighted:(BOOL)newHighlighted {
    [super setHighlighted:newHighlighted];
    [self stateWasUpdated];
}

- (void)setEnabled:(BOOL)newEnabled {
    [super setEnabled:newEnabled];
    [self stateWasUpdated];
}

- (void)stateWasUpdated {
    // Add your custom code here to respond to the change in state
}

@end

Answer 2

根据@Nick的回答,我实现了一个更简单的版本.此子类公开一个BOOL outlined与函数类似的属性selected,highlighted和enabled.

在[customButtton setImage:[UIImage imageNamed:@"MyOutlinedButton.png"] forState:UIControlStateOutlined]更新outlined属性时,做一些事情会使它自动运行.

如果需要,可以添加更多这些州+财产.

UICustomButton.h

extern const UIControlState UIControlStateOutlined;

@interface UICustomButton : UIButton
@property (nonatomic) BOOL outlined;
@end

UICustomButton.m

const UIControlState UIControlStateOutlined = (1 << 16);

@interface OEButton ()
@property UIControlState customState;
@end

@implementation OEButton

- (void)setOutlined:(BOOL)outlined
{
    if (outlined)
    {
        self.customState |= UIControlStateOutlined;
    }
    else
    {
        self.customState &= ~UIControlStateOutlined;
    }
    [self stateWasUpdated];
}

- (BOOL)outlined
{
    return ( self.customState & UIControlStateOutlined ) == UIControlStateOutlined;
}

- (UIControlState)state {
    return [super state] | self.customState;
}

- (void)stateWasUpdated
{
    [self setNeedsLayout];
}

// These are only needed if you have additional code on -(void)stateWasUpdated
// - (void)setSelected:(BOOL)newSelected
// {
//     [super setSelected:newSelected];
//     [self stateWasUpdated];
// }
//
// - (void)setHighlighted:(BOOL)newHighlighted
// {
//     [super setHighlighted:newHighlighted];
//     [self stateWasUpdated];
// }
//
// - (void)setEnabled:(BOOL)newEnabled
// {
//     [super setEnabled:newEnabled];
//     [self stateWasUpdated];
// }

@end