Customize UISlider (track image height)

问题:

I'm customizing a UISlider. I could set a custom thumb image that is higher than the usual thumb however I could not make the track higher when setting a higher minimum track image but the track height remained the same. It should be possible as in the iPod/Music App on the iPad the volume slider is also higher as the usual slider as you can see here:

http://blog.cocoia.com/wp-content/uploads/2010/01/Lol-wut.png

回答1:

You need to subclass the slider and override the trackRectForBounds: method, like this:

- (CGRect)trackRectForBounds:(CGRect)bounds
{
    return bounds;
}

回答2:

The simplest solution for Swift:

class TBSlider: UISlider {

    override func trackRectForBounds(bounds: CGRect) -> CGRect {
        return CGRectMake(0, 0, bounds.size.width, 4)
    }
}

回答3:

use next methods setThumbImage, setMinimumTrackImage, setMaximumTrackImage

[self setThumbImage:[UIImage imageNamed:@"switchThumb.png"] forState:UIControlStateNormal];
    [self setMinimumTrackImage:[UIImage imageNamed:@"switchBlueBg.png"] forState:UIControlStateNormal];
    [self setMaximumTrackImage:[UIImage imageNamed:@"switchOffPlain.png"] forState:UIControlStateNormal];

and create subclass like this

- (id) initWithFrame: (CGRect)rect{
    if ((self=[super initWithFrame:CGRectMake(rect.origin.x,rect.origin.y,90,27)])){
        [self awakeFromNib];
    }
    return self;
}

回答4:

For those that would like to see some working code for changing the track size.

class CustomUISlider : UISlider
{        
    override func trackRectForBounds(bounds: CGRect) -> CGRect {
        //keeps original origin and width, changes height, you get the idea
        let customBounds = CGRect(origin: bounds.origin, size: CGSize(width: bounds.size.width, height: 5.0))
        super.trackRectForBounds(customBounds)
        return customBounds
    }

    //while we are here, why not change the image here as well? (bonus material)
    override func awakeFromNib() {
        self.setThumbImage(UIImage(named: "customThumb"), forState: .Normal)
        super.awakeFromNib()
    }
}

Only thing left is changing the class inside the storyboard:

You can keep using your seekbar action and outlet to the object type UISlider, unless you want to add some more custom stuff to your slider.

回答5:

//use this code

 UIImage *volumeLeftTrackImage = [[UIImage imageNamed: @"video_payer_scroll_selection.png"] stretchableImageWithLeftCapWidth: 9 topCapHeight: 0];
        UIImage *volumeRightTrackImage= [[UIImage imageNamed: @"video_bar_bg.png"] stretchableImageWithLeftCapWidth: 9 topCapHeight: 0];
        [volumeslider setMinimumTrackImage: volumeLeftTrackImage  forState: UIControlStateNormal];
        [volumeslider setMaximumTrackImage: volumeRightTrackImage  forState: UIControlStateNormal];
        [volumeslider setThumbImage:[UIImage imageNamed:@"sound_bar_btn.png"] forState:UIControlStateNormal];
        [tempview addSubview:volumeslider];