UISlider 设置增量

    UISlider *slier = [[UISlider alloc]initWithFrame:CGRectMake(wu500.right, 0, 210, 50)];
    slier.minimumValue = 500;
    slier.maximumValue = 4000;
    slier.thumbTintColor = [UIColor redColor];
    [self.view addSubview:slier];
    [slier addTarget:self action:@selector(sliderValueChanges:) forControlEvents:UIControlEventValueChanged];

- (void)sliderValueChanges:(UISlider *)slider
{
    [slider setValue:((int)((slider.value + 250) / 500) * 500) animated:YES];
    NSLog(@"line(%d): %@,%f",__LINE__,@"slider value ->",slider.value);
}