我将从UI截图开始,更准确地描绘我的问题：
每当我向单元格引入新的价值时,我想为这个最左边的灯泡设置动画,让它看起来像是充满了红色.
这是BadgeView的实现,它基本上是前面提到的最左边的圆圈
class BadgeView: UIView {
var coeff:CGFloat = 0.5
override func drawRect(rect: CGRect) {
let topRect:CGRect = CGRectMake(0,rect.size.width,rect.size.height*(1.0 - self.coeff))
UIColor(red: 249.0/255.0,green: 163.0/255.0,blue: 123.0/255.0,alpha: 1.0).setFill()
UIRectFill(topRect)
let bottomRect:CGRect = CGRectMake(0,rect.size.height*(1-coeff),rect.size.height*coeff)
UIColor(red: 252.0/255.0,green: 95.0/255.0,blue: 95.0/255.0,alpha: 1.0).setFill()
UIRectFill(bottomRect)
self.layer.cornerRadius = self.frame.height/2.0
self.layer.masksToBounds = true
}
}
这是我实现不均匀填充的方式 – 我引入了在viewController中修改的系数.
在我的cellForRowAtIndexPath方法中,我尝试使用带回调的自定义按钮为此形状设置动画
let btn:MGSwipeButton = MGSwipeButton(title: "",icon: img,backgroundColor: nil,insets: ins,callback: {
(sender: MGSwipeTableCell!) -> Bool in
print("Convenience callback for swipe buttons!")
UIView.animateWithDuration(4.0,animations:{ () -> Void in
cell.pageBadgeView.coeff = 1.0
let frame:CGRect = cell.pageBadgeView.frame
cell.pageBadgeView.drawRect(frame)
})
return true
})
但它只会打印到控制台
: CGContextSetFillColorWithColor: invalid context 0x0. If you want to see the backtrace,please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
解决方法
cell.pageBadgeView.drawRect(frame)
从UIView上的Apple docs drawRect：
This method is called when a view is first displayed or when an event occurs that invalidates a visible part of the view. You should never call this method directly yourself. To invalidate part of your view,and thus cause that portion to be redrawn,call the setNeedsDisplay or setNeedsDisplayInRect: method instead.
因此,如果您将代码更改为：
cell.pageBadgeView.setNeedsDisplay()
您将摆脱错误并看到badgeView正确填充.但是这不会为它设置动画,因为默认情况下drawRect不可动画.
解决问题的最简单方法是让BadgeView拥有填充颜色的内部视图.我将重构BadgeView如下：
class BadgeView: UIView {
private let fillView = UIView(frame: CGRectZero)
private var coeff:CGFloat = 0.5 {
didSet {
// Make sure the fillView frame is updated everytime the coeff changes
updateFillViewFrame()
}
}
// Only needed if view isn't created in xib or storyboard
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
// Only needed if view isn't created in xib or storyboard
override init(frame: CGRect) {
super.init(frame: frame)
setupView()
}
override func awakeFromNib() {
setupView()
}
private func setupView() {
// Setup the layer
layer.cornerRadius = bounds.height/2.0
layer.masksToBounds = true
// Setup the unfilled backgroundColor
backgroundColor = UIColor(red: 249.0/255.0,alpha: 1.0)
// Setup filledView backgroundColor and add it as a subview
fillView.backgroundColor = UIColor(red: 252.0/255.0,alpha: 1.0)
addSubview(fillView)
// Update fillView frame in case coeff already has a value
updateFillViewFrame()
}
private func updateFillViewFrame() {
fillView.frame = CGRectMake(0,bounds.height*(1-coeff),bounds.width,bounds.height*coeff)
}
// Setter function to set the coeff animated. If setting it not animated isn't necessary at all,consider removing this func and animate updateFillViewFrame() in coeff didSet
func setCoeff(coeff: CGFloat,animated: Bool) {
if animated {
UIView.animateWithDuration(4.0,animations:{ () -> Void in
self.coeff = coeff
})
} else {
self.coeff = coeff
}
}
}
在你的按钮回调中你只需要做：
cell.pageBadgeView.setCoeff(1.0,animated: true)
