UI: UISlider 实现指定范围值的选择

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    _mySlider = [[UISlider alloc]initWithFrame:CGRectMake(0, 0, 200, 23)];
    _mySlider.center = self.view.center;
    _mySlider.minimumValue = 0.0f;
    _mySlider.maximumValue = 100.0f;
    _mySlider.value = _mySlider.maximumValue/2.0;
    
    [self.view addSubview:_mySlider];
}