自定义UISlider

UIImage *stretch = [[UIImage imageNamed:@"slider-bg.png"] stretchableImageWithLeftCapWidth:10.0 topCapHeight:0.0];
slider.backgroundColor = [UIColor clearColor];
[slider setThumbImage: [UIImage imageNamed:@"slider-knob.png"] forState:UIControlStateNormal];
[slider setMinimumTrackImage:stretch forState:UIControlStateNormal];
[slider setMaximumTrackImage:stretch forState:UIControlStateNormal];
slider.minimumValue = 0.0;
slider.maximumValue = 100.0;
slider.continuous = YES;
slider.value = 50.0;

示例图：