使用 minimumImageValue / maximumImageValue 更改 UISlider 值

Posted 2023-03-13

【中文标题】使用 minimumImageValue / maximumImageValue 更改 UISlider 值

【英文标题】：Change UISlider value using minimumImageValue / maximumImageValue

【发布时间】：2012-10-31 13:12:16

【问题描述】：

我想让 UISlider 响应点击minimumValueImage 和/或maximumValueImage，将值设置为最小值或最大值。对于这种情况，我似乎找不到“正常”的方法，所以我想出了这个解决方案。我正在继承 UISlider 并记录用户开始触摸的位置。通过比较位置，我可以确定它是否在其中一张图像上。工作正常，但有没有更不习惯的方法来实现相同的目标？

@interface FGSlider ()

@property (nonatomic) CGRect minimumValueImageRect;
@property (nonatomic) CGRect maximumValueImageRect;

@property (nonatomic) BOOL touchesBeganInMinimumValueImageRect;
@property (nonatomic) BOOL touchesBeganInMaximumValueImageRect;

@end

@implementation FGSlider

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
    [super touchesBegan:touches withEvent:event];

    UITouch *touch = [touches anyObject];

    CGPoint location = [touch locationInView:self];
    if(CGRectContainsPoint(self.minimumValueImageRect, location)) 
        self.touchesBeganInMinimumValueImageRect = YES;
    
    else if(CGRectContainsPoint(self.maximumValueImageRect, location)) 
        self.touchesBeganInMaximumValueImageRect = YES;
    

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
    [super touchesEnded:touches withEvent:event];

    UITouch *touch = [touches anyObject];

    CGPoint location = [touch locationInView:self];
    if(self.touchesBeganInMinimumValueImageRect && CGRectContainsPoint(self.minimumValueImageRect, location)) 
        [self setValue:self.minimumValue animated:YES];
        [self sendActionsForControlEvents:UIControlEventValueChanged];
    
    else if(self.touchesBeganInMaximumValueImageRect && CGRectContainsPoint(self.maximumValueImageRect, location)) 
        [self setValue:self.maximumValue animated:YES];
        [self sendActionsForControlEvents:UIControlEventValueChanged];
    

    // reset state
    self.touchesBeganInMinimumValueImageRect = NO;
    self.touchesBeganInMinimumValueImageRect = NO;



-(CGRect)minimumValueImageRectForBounds:(CGRect)bounds 
    self.minimumValueImageRect = [super minimumValueImageRectForBounds:bounds];
    return self.minimumValueImageRect;


-(CGRect)maximumValueImageRectForBounds:(CGRect)bounds 
    self.maximumValueImageRect = [super maximumValueImageRectForBounds:bounds];
    return self.maximumValueImageRect;

@end

【问题讨论】：

曾经得到这个答案吗？

很遗憾，没有。但是我的实现是有效的，所以我已经解决了。

我已经把解决方案放到了github上，有兴趣的朋友：github.com/fguchelaar/FGSlider

【参考方案1】：

我创建了一个简单的类别，它似乎可以工作并且不依赖于计算界限，并且比您的实现简单得多。试试看，让我知道你的想法。

- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
    UITouch *touch = [touches anyObject];
    for (UIView *view in self.subviews) 
        CGPoint locationPoint = [touch locationInView:view];
        if ([view pointInside:locationPoint withEvent:event]) 
            UIImageView *imageView = (UIImageView*)view;
            if (imageView.image == self.maximumValueImage) 
                [self setValue:self.maximumValue animated:YES];
                [self sendActionsForControlEvents:UIControlEventValueChanged];
             else if (imageView.image == self.minimumValueImage) 
                [self setValue:self.minimumValue animated:YES];
                [self sendActionsForControlEvents:UIControlEventValueChanged];
            
        
    
    [super touchesBegan:touches withEvent:event];