自定义UISlider样式

    UIImage *thumbImageNormal = [UIImage imageNamed:@"SliderThumb-Normal"];
    [self.slider setThumbImage:thumbImageNormal forState:UIControlStateNormal];
    
    UIImage *thumbImageHighlight = [UIImage imageNamed:@"SliderThumb-Highlight"];
    [self.slider setThumbImage:thumbImageHighlight forState:UIControlStateHighlighted];
    
    UIImage *trackLeftImage = [[UIImage imageNamed:@"SliderTrackLeft"] stretchableImageWithLeftCapWidth:14 topCapHeight:0];
    [self.slider setMinimumTrackImage:trackLeftImage forState:UIControlStateNormal];
    
    UIImage *trackRightImage = [[UIImage imageNamed:@"SliderTrackRight"] stretchableImageWithLeftCapWidth:14 topCapHeight:0];
    [self.slider setMaximumTrackImage:trackRightImage forState:UIControlStateNormal];