自定义UISlider - 增加"热点"大小

Question

我有一个定制的UISlider,对于大手指的人来说,由于"拇指图像"的大小而难以抓住并滑动.有没有办法在不改变图像大小的情况下增加可点击/可拖动区域的大小？

这是我创建自定义滑块的代码,如果有帮助的话:

[slider setMaximumTrackImage:[[UIImage imageNamed:@"max.png"]
                                             resizableImageWithCapInsets:UIEdgeInsetsMake(0, 20, 0, 20)]
                                   forState:UIControlStateNormal];
[slider setMinimumTrackImage:[[UIImage imageNamed:@"min.png"]
                                             resizableImageWithCapInsets:UIEdgeInsetsMake(0, 20, 0, 20)]
                                   forState:UIControlStateNormal];
[slider setThumbImage:[UIImage imageNamed:@"thumb.png"]
                            forState:UIControlStateNormal];

Answer 1

我最终继承了UISlider并重写了这个方法:

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent*)event {
    CGRect bounds = self.bounds;
    bounds = CGRectInset(bounds, -10, -15);
    return CGRectContainsPoint(bounds, point);
}

这使得可触摸区域在左侧和右侧延伸10个像素,在顶部和底部延伸15个像素.

Answer 2

此解决方案适用于iOS 8:

class ExtUISlider: UISlider {

    var thumbTouchSize : CGSize = CGSizeMake(50, 50)

    override func pointInside(point: CGPoint, withEvent event: UIEvent?) -> Bool {
        let bounds = CGRectInset(self.bounds, -thumbTouchSize.width, -thumbTouchSize.height);
        return CGRectContainsPoint(bounds, point);
    }

    override func beginTrackingWithTouch(touch: UITouch, withEvent event: UIEvent) -> Bool {
        let thumbPercent = (value - minimumValue) / (maximumValue - minimumValue)
        let thumbSize = thumbImageForState(UIControlState.Normal)!.size.height
        let thumbPos = CGFloat(thumbSize) + (CGFloat(thumbPercent) * (CGFloat(bounds.size.width) - (2 * CGFloat(thumbSize))))
        let touchPoint = touch.locationInView(self)

        return (touchPoint.x >= (thumbPos - thumbTouchSize.width) &&
            touchPoint.x <= (thumbPos + thumbTouchSize.width))
    }
}

积分转到这篇文章:http://www.mpatric.com/2009-04-15-more-responsive-sliders-on-the-iphone

Answer 3

斯威夫特3

UISlider增加触摸面积的子类

class CustomSlider: UISlider {

    private var thumbTouchSize = CGSize(width: 40, height: 40)

    override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
        let increasedBounds = bounds.insetBy(dx: -thumbTouchSize.width, dy: -thumbTouchSize.height)
        let containsPoint = increasedBounds.contains(point)
        return containsPoint
    }

    override func beginTracking(_ touch: UITouch, with event: UIEvent?) -> Bool {
        let percentage = CGFloat((value - minimumValue) / (maximumValue - minimumValue))
        let thumbSizeHeight = thumbRect(forBounds: bounds, trackRect:trackRect(forBounds: bounds), value:0).size.height
        let thumbPosition = thumbSizeHeight + (percentage * (bounds.size.width - (2 * thumbSizeHeight)))
        let touchLocation = touch.location(in: self)
        return touchLocation.x <= (thumbPosition + thumbTouchSize.width) && touchLocation.x >= (thumbPosition - thumbTouchSize.width)
    }
}