自定义 UISlider 无法正确设置最小轨道颜色

Question

I've subclassed UISlider and increased the width by doing this:

-(CGRect)trackRectForBounds:(CGRect)bounds {

bounds.size.height = 50;
return bounds;

}

And changed the thumb image:

- (void)drawRect:(CGRect)rect {
// Drawing code
[self setThumbImage:[UIImage imageNamed:@"icon_circle"] forState:UIControlStateNormal];
}

But this is happening:

The minimum track image starts from the center. I want to make it start from the thumb end. So initially, till the thumb it should be blue and when I drag it till the end the whole slider should be blue but at the end of the slider, the slider is not curved. It has got sharped edges. What should I do to get this right?

Answer 1

Couldn't find much help so I made my own custom one instead. It's also available on GitHub. https://github.com/bhavukjain1/SlideToActionSlideriOS

Answer 2

Are you setting the following properties?

UIImage *minImage = [[UIImage imageNamed:@"slider_minimum.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 5, 0, 0)];
UIImage *maxImage = [[UIImage imageNamed:@"slider_maximum.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 5)];
UIImage *thumbImage = [UIImage imageNamed:@"sliderhandle.png"];

[[UISlider appearance] setMaximumTrackImage:maxImage forState:UIControlStateNormal];
[[UISlider appearance] setMinimumTrackImage:minImage forState:UIControlStateNormal];
[[UISlider appearance] setThumbImage:thumbImage forState:UIControlStateNormal];

}

if so, take a look at this tutorial of how to create a custom slider, it comes with a sample project, may be it's easier for you to find your error by comparing your implementation against a working one.

Answer 3

To solve the rectangular corners issue, in drawRect

self.layer.cornerRadius = 25;
self.clipsToBounds = YES;

To show the correct image while dragging, you need to set this as well:

[self setThumbImage:[UIImage imageNamed:@"icon_circle"] forState:UIControlStateHighlighted];