如果开始用图形自定义 UISlider,则必须设置至少 3 个图形。轨迹栏的左右两侧和拇指图像:
这是我上次使用 UISlider 时的做法:
CGRect frame = CGRectMake(20.0f, 6.0, 280.0f, 20.0f);
UISlider *customSlider = [[UISlider alloc] initWithFrame:frame];
[customSlider addTarget:self action:@selector(sliderMove:) forControlEvents:UIControlEventValueChanged];
[customSlider addTarget:self action:@selector(sliderStart:) forControlEvents:UIControlEventTouchDown];
[customSlider addTarget:self action:@selector(sliderEnd:) forControlEvents:UIControlEventTouchUpInside];
[customSlider addTarget:self action:@selector(sliderEnd:) forControlEvents:UIControlEventTouchUpOutside];
// in case the parent view draws with a custom color or gradient, use a transparent color
customSlider.backgroundColor = [UIColor clearColor];
UIImage *stetchLeftTrack = [[UIImage imageNamed:@"slider.png"]
stretchableImageWithLeftCapWidth:10.0 topCapHeight:0.0];
UIImage *stetchRightTrack = [[UIImage imageNamed:@"slider_right.png"]
stretchableImageWithLeftCapWidth:10.0 topCapHeight:0.0];
[customSlider setThumbImage: [UIImage imageNamed:@"slider-knop.png"] forState:UIControlStateNormal];
[customSlider setMinimumTrackImage:stetchLeftTrack forState:UIControlStateNormal];
[customSlider setMaximumTrackImage:stetchRightTrack forState:UIControlStateNormal];
在我的光学系统中,UISlider 或任何其他状态的突出显示状态是没有意义的,您的手指可能会覆盖拇指图像,因此用户永远不会看到它。我不确定它只是从 UIButton 扩展而来,也许它无法处理它?