根据在线文章并使用 github 项目,我能够创建一个带有第二条轨道 (bufferTrack) 的 UISlider
。
我面临的唯一问题是更新 burrerEndValue/value。它不是动画。如何在 UIBezierPath 上实现流畅的动画?
open class BufferSlider: UISlider {
open var bufferStartValue:Double = 0 {
didSet{
if bufferStartValue < 0.0 {
bufferStartValue = 0
}
if bufferStartValue > bufferEndValue {
bufferStartValue = bufferEndValue
}
self.setNeedsDisplay()
}
}
open var bufferEndValue:Double = 0 {
didSet{
if bufferEndValue > 1.0 {
bufferEndValue = 1
}
if bufferEndValue < bufferStartValue{
bufferEndValue = bufferStartValue
}
self.setNeedsDisplay()
}
}
open var baseColor:UIColor = UIColor.white
open var progressColor:UIColor?
open var bufferColor:UIColor?
open var customBorderWidth: Double = 0.1{
didSet{
if customBorderWidth < 0.1 {
customBorderWidth = 0.1
}
self.setNeedsDisplay()
}
}
open var sliderHeight: Double = 6 {
didSet{
if sliderHeight < 1 {
sliderHeight = 1
}
}
}
override open func setValue(_ value: Float, animated: Bool) {
super.setValue(value, animated: animated)
self.setNeedsDisplay()
}
override init(frame: CGRect) {
super.init(frame: frame)
updateView()
}
required public init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
updateView()
}
func updateView() {
baseColor = UIColor.white
progressColor = appColors.red
bufferColor = appColors.fadedRed
}
open override func trackRect(forBounds bounds: CGRect) -> CGRect {
var result = super.trackRect(forBounds: bounds)
result.size.height = 0.01
return result
}
open override func draw(_ rect: CGRect) {
baseColor.set()
let rect = self.bounds.insetBy(dx: CGFloat(customBorderWidth), dy: CGFloat(customBorderWidth))
let height = sliderHeight.CGFloatValue
let radius = height/2
let sliderRect = CGRect(x: rect.origin.x, y: rect.origin.y + (rect.height/2-radius), width: rect.width, height: rect.width) //default center
let path = UIBezierPath()
path.addArc(withCenter: CGPoint(x: sliderRect.minX + radius, y: sliderRect.minY+radius), radius: radius, startAngle: CGFloat(Double.pi)/2, endAngle: -CGFloat(Double.pi)/2, clockwise: true)
path.addLine(to: CGPoint(x: sliderRect.maxX-radius, y: sliderRect.minY))
path.addArc(withCenter: CGPoint(x: sliderRect.maxX-radius, y: sliderRect.minY+radius), radius: radius, startAngle: -CGFloat(Double.pi)/2, endAngle: CGFloat(Double.pi)/2, clockwise: true)
path.addLine(to: CGPoint(x: sliderRect.minX + radius, y: sliderRect.minY+height))
baseColor.setStroke()
path.lineWidth = customBorderWidth.CGFloatValue
path.stroke()
path.fill()
path.addClip()
var fillHeight = sliderRect.size.height-customBorderWidth.CGFloatValue
if fillHeight < 0 {
fillHeight = 0
}
let fillRect = CGRect(
x: sliderRect.origin.x + sliderRect.size.width*CGFloat(bufferStartValue),
y: sliderRect.origin.y + customBorderWidth.CGFloatValue/2,
width: sliderRect.size.width*CGFloat(bufferEndValue-bufferStartValue),
height: fillHeight)
if let color = bufferColor { color.setFill() }
else if let color = self.superview?.tintColor{ color.setFill()}
else{ UIColor(red: 0.0, green: 122.0/255.0, blue: 1.0, alpha: 1.0).setFill() }
UIBezierPath(rect: fillRect).fill()
if let color = progressColor{
color.setFill()
let fillRect = CGRect(
x: sliderRect.origin.x,
y: sliderRect.origin.y + customBorderWidth.CGFloatValue/2,
width: sliderRect.size.width*CGFloat((value-minimumValue)/(maximumValue-minimumValue)),
height: fillHeight)
UIBezierPath(rect: fillRect).fill()
}
}
}
extension Double{
var CGFloatValue: CGFloat {
return CGFloat(self)
}
}
最佳答案
当您在 draw(rect:)
函数中为它实现自定义绘图时,您不能为 UIView
实例设置动画,因为在动画期间 self.layer. presentationLayer
必须使用 oldValue
和 newValue
之间的插值绘制,但是您重写的绘制逻辑始终使用新设置的值 newValue
.
您可以只在 CALayer
实例中使用您想要的动画进行自定义绘制。
考虑在 BufferSliderLayer: CALayer
中实现您的绘图逻辑。
对于层上的动画,您需要插入要设置动画的值,例如bufferEndValue
和 value
。
为此,您可以引用this article .
然后,只需将 BufferSliderLayer
添加到 slider 的 init(frame:)
初始化器中的 BufferSlider
View 层上,并在 中适当调整层大小>布局 subview
。
关于ios - 动画 UISlider 的缓冲区轨道变化?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56414915/