UISlider 设置每次滑动的固定值

 

@interface MyViewController : UIViewController {

    UISlider *slider;

    NSArray *numbers;

}

@end

 

@implementation MyViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    slider = [[UISlider alloc] initWithFrame:self.view.bounds];

    [self.view addSubview:slider];

 

    // These number values represent each slider position

    numbers = @[@(-3), @(0), @(2), @(4), @(7), @(10), @(12)];

    // slider values go from 0 to the number of values in your numbers array

    NSInteger numberOfSteps = ((float)[numbers count] - 1);

    slider.maximumValue = numberOfSteps;

    slider.minimumValue = 0;

 

    // As the slider moves it will continously call the -valueChanged: 

    slider.continuous = YES; // NO makes it call only once you let go

    [slider addTarget:self

               action:@selector(valueChanged:)

     forControlEvents:UIControlEventValueChanged];

}

- (void)valueChanged:(UISlider *)sender {

    // round the slider position to the nearest index of the numbers array

    NSUInteger index = (NSUInteger)(slider.value + 0.5);

    [slider setValue:index animated:NO];

    NSNumber *number = numbers[index]; // <-- This numeric value you want

    NSLog(@"sliderIndex: %i", (int)index);

    NSLog(@"number: %@", number);

}