A UISlider subclass that displays the slider value in a popup view
Objective-C Ruby

README.md

ASValueTrackingSlider

What is it?

A UISlider subclass that displays live values in an easy to customize popup view.

screenshot

If you'd like the same functionality for UIProgressView then check out ASProgressPopupView.

Features

  • Live updating of UISlider value
  • Customizable properties:

    • textColor
    • font
    • popUpViewColor
    • popUpViewAnimatedColors - popUpView and UISlider track color animate as value changes
    • popUpViewCornerRadius
    • popUpViewArrowLength
  • Set your own NSNumberFormatter to control the displayed values

  • Optional dataSource - supply your own custom text to the popUpView label
  • Wholesome springy animation

Which files are needed?

For CocoaPods users, simply add pod 'ASValueTrackingSlider' to your podfile. If you'd like to test the included demo project before including it in your own work, then type $ pod try ASValueTrackingSlider in the terminal. CocoaPods will download the demo project into a temp folder and open it in Xcode. Magic.

If you don't use CocoaPods, just include these files in your project:

  • ASValueTrackingSlider (.h .m)
  • ASValuePopUpView (.h .m)

How to use it

It’s very simple. Drag a UISlider into your Storyboard/nib and set its class to ASValueTrackingSlider – that's it. The examples below demonstrate how to customize the appearance and value displayed.

self.slider.maximumValue = 255.0;
self.slider.popUpViewCornerRadius = 12.0;
[self.slider setMaxFractionDigitsDisplayed:0];
self.slider.popUpViewColor = [UIColor colorWithHue:0.55 saturation:0.8 brightness:0.9 alpha:0.7];
self.slider.font = [UIFont fontWithName:@"GillSans-Bold" size:22];
self.slider.textColor = [UIColor colorWithHue:0.55 saturation:1.0 brightness:0.5 alpha:1];

screenshot

NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
[formatter setNumberStyle:NSNumberFormatterPercentStyle];
[self.slider setNumberFormatter:formatter];
self.slider.popUpViewAnimatedColors = @[[UIColor purpleColor], [UIColor redColor], [UIColor orangeColor]];
self.slider.font = [UIFont fontWithName:@"Futura-CondensedExtraBold" size:26];

screenshot

The popUpView adjusts itself so that it doesn't extend beyond the width of the slider control.

How to use custom strings in popUpView label

Set your controller as the dataSource to ASValueTrackingSlider and adopt the ASValueTrackingSliderDataSource, then return NSStrings for any values you want to customize.

// slider has a custom NSNumberFormatter to display temperature in °C
// the dataSource method below returns custom NSStrings for specific values
- (NSString *)slider:(ASValueTrackingSlider *)slider stringForValue:(float)value;
{
    value = roundf(value);
    NSString *s;
    if (value < -10.0) {
        s = @"❄️Brrr!⛄️";
    } else if (value > 29.0 && value < 50.0) {
        s = [NSString stringWithFormat:@"😎 %@ 😎", [slider.numberFormatter stringFromNumber:@(value)]];
    } else if (value >= 50.0) {
        s = @"I’m Melting!";
    }
    return s;
}

screenshot

How to use with UITableView

To use effectively inside a UITableView you need to implement the <ASValueTrackingSliderDelegate> protocol. If you just embed an ASValueTrackingSlider inside a UITableViewCell the popUpView will probably be obscured by the cell above. The delegate method notifies you before the popUpView appears so that you can ensure that your UITableViewCell is rendered above the others.

The recommended technique for use with UITableView is to create a UITableViewCell subclass that implements the delegate method.

 @interface SliderCell : UITableViewCell <ASValueTrackingSliderDelegate>
 @property (weak, nonatomic) IBOutlet ASValueTrackingSlider *slider;
 @end

 @implementation SliderCell
 - (void)awakeFromNib
 {
    self.slider.delegate = self;
 }

 - (void)sliderWillDisplayPopUpView:(ASValueTrackingSlider *)slider;
 {
    [self.superview bringSubviewToFront:self];
 }
 @end