Implementing steps/snapping UISlider

Question

I am trying to implement some form of snapping or steps with the UISlider. I have written the following code but it does not work as smooth as I hoped for. It works, but when the I slide it upwards it snap 5points to the right leaving the finger not centered over the "slide-circle"

This is my code where self.lastQuestionSliderValue is a property of the class which I have set to the initial value of the slider.

    if (self.questionSlider.value > self.lastQuestionSliderValue) {         self.questionSlider.value += 5.0;     } else {         self.questionSlider.value -= 5.0;     }      self.lastQuestionSliderValue = (int)self.questionSlider.value; 

Answer 1

It's actually considerably easier than I first thought. Originally I was trying to get the thumbrect property and do complicated math. Here's what I ended up with:

h File:

@property (nonatomic, retain) IBOutlet UISlider* questionSlider; @property (nonatomic) float lastQuestionStep; @property (nonatomic) float stepValue; 

m File:

- (void)viewDidLoad {     [super viewDidLoad];      // Set the step to whatever you want. Make sure the step value makes sense     //   when compared to the min/max values for the slider. You could take this     //   example a step further and instead use a variable for the number of     //   steps you wanted.     self.stepValue = 25.0f;      // Set the initial value to prevent any weird inconsistencies.     self.lastQuestionStep = (self.questionSlider.value) / self.stepValue; }  // This is the "valueChanged" method for the UISlider. Hook this up in //   Interface Builder. -(IBAction)valueChanged:(id)sender {     // This determines which "step" the slider should be on. Here we're taking      //   the current position of the slider and dividing by the `self.stepValue`     //   to determine approximately which step we are on. Then we round to get to     //   find which step we are closest to.     float newStep = roundf((questionSlider.value) / self.stepValue);      // Convert "steps" back to the context of the sliders values.     self.questionSlider.value = newStep * self.stepValue; } 

Make sure you hook up the method and the outlet for your UISlider view and you should be good to go.