Question

Does anyone know how to set the start position of a UISlider (ideally in the middle) and also how to increment it in tens instead of ones?

Here’s what I’ve got so far:

// Setup custom slider images
UIImage *minImage = [UIImage imageNamed:@"ins_blueTrack.png"];
UIImage *maxImage = [UIImage imageNamed:@"ins_whiteTrack.png"];
UIImage *tumbImage= [UIImage imageNamed:@"slide.png"];

minImage=[minImage stretchableImageWithLeftCapWidth:6.0 topCapHeight:0.0];
maxImage=[maxImage stretchableImageWithLeftCapWidth:6.0 topCapHeight:0.0];

// Setup the  slider
[self.slider setMinimumTrackImage:minImage forState:UIControlStateNormal];
[self.slider setMaximumTrackImage:maxImage forState:UIControlStateNormal];
[self.slider setThumbImage:tumbImage forState:UIControlStateNormal];

self.slider.minimumValue = 10;
self.slider.maximumValue = 180;
self.slider.continuous = YES;

int myVal = self.slider.value;
NSString *timeValue = [[NSString alloc] initWithFormat:@"%1d", myVal];

self.timeLabel.text = timeValue;

// Attach an action to sliding
[self.slider addTarget:self action:@selector(fxSliderAction) forControlEvents:UIControlEventValueChanged];

Answer 1

Setting the Slider Position

In keeping with your code you could have:

self.slider.value = (90);

Note: there is no real need for self when you’re referencing the IBOutlet from the same class.

If you want a truly dynamic way of setting the UISlider to the halfway mark, you would just divide your maximum value by 2, effectively halving it:

self.slider.value = (self.slider.maximumValue / 2);

Incrementing in Multiples of 10

For this I would suggest something slightly different to what you currently have. Instead of having a minimum of 10 and a maximum of 180, what about a minimum of 1 and a maximum of 18?

self.slider.minimumValue = 1;
self.slider.maximumValue = 18;

Every time you retrieve the value of the slider, just multiply it by 10. This way the slider moves to 18 different locations (as you wanted), and you always get a multiple of 10.

int trueSliderValue = self.slider.value * 10;