Created
January 28, 2020 08:31
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| //MARK: - common init | |
| private func commonInit(){ | |
| shapeLayer.fillColor = setFillColor.cgColor | |
| shapeLayer.actions = ["path" : NSNull(), "position" : NSNull(), "bounds" : NSNull()] | |
| layer.addSublayer(shapeLayer) | |
| shapeLayer.masksToBounds = true | |
| circleLayer.lineWidth = 4 | |
| circleLayer.strokeColor = setRefreshCircleColor.cgColor | |
| circleLayer.fillColor = UIColor.clear.cgColor | |
| circleLayer.actions = ["path" : NSNull(), "position" : NSNull(), "bounds" : NSNull()] | |
| layer.addSublayer(circleLayer) | |
| } | |
| //MARK: - draw rect | |
| override func draw(_ rect: CGRect) { | |
| guard let _ = containerScrollView else {return} | |
| calculate(rect) | |
| leftTop = CGPoint(x: rect.minX, y: rect.minY) | |
| rightTop = CGPoint(x: rect.maxX, y: rect.minY) | |
| leftBottom = CGPoint(x: rect.minX, y: edgeBottomPointYOffset) | |
| rightBottom = CGPoint(x: rect.maxX, y: edgeBottomPointYOffset) | |
| midBottom = CGPoint(x: xPositionOfPan, y: middleBottomPointYOffset) | |
| ///border path of refresh control | |
| let path = CGMutablePath() | |
| path.move(to: leftTop) | |
| path.addLine(to: leftBottom) | |
| path.addLine(to: midBottom) | |
| path.addLine(to: rightBottom) | |
| path.addLine(to: rightTop) | |
| path.closeSubpath() | |
| shapeLayer.path = path | |
| if !refreshingStatus { | |
| ///circle refresh path | |
| let draggedFractionCompleted = edgeBottomPointYOffset / thresholdDrag | |
| let circlePath = UIBezierPath(arcCenter: CGPoint(x: 0, y: 0), radius: refreshCircleSize.rawValue, startAngle: getStartAngle(draggedFractionCompleted), endAngle: getStartAngle(draggedFractionCompleted + 0.85), clockwise: true) | |
| circleLayer.path = circlePath.cgPath | |
| } | |
| } | |
| //MARK: - calculation | |
| /// calculates all required dynamic variables and sets frame of layers | |
| /// - Parameter rect: CGRect of view's frame | |
| private func calculate(_ rect : CGRect){ | |
| //guard "scrollViewContentYOffset" to be greater than zero | |
| //i.e. user is dragging scroll view downward such that actual content offset of scroll view is negative | |
| guard scrollViewContentYOffset >= 0 else { | |
| middleBottomPointYOffset = 0 | |
| edgeBottomPointYOffset = 0 | |
| return | |
| } | |
| //calculating y offsets of points | |
| //if refreshing status is false then we have to draw V shape at bottom | |
| if !refreshingStatus{ | |
| middleBottomPointYOffset = min(scrollViewContentYOffset, maxHeightOfRefreshControl) | |
| edgeBottomPointYOffset = max((middleBottomPointYOffset - 20),0) | |
| }else{ | |
| //else if refreshing status is true then --- straight line at bottom | |
| middleBottomPointYOffset = min(scrollViewContentYOffset, thresholdDrag) | |
| edgeBottomPointYOffset = middleBottomPointYOffset | |
| //then set scroll view's content inset | |
| containerScrollView?.contentInset.top = middleBottomPointYOffset | |
| } | |
| //calculating frame of layer | |
| shapeLayer.frame = CGRect(x: 0, y: 0, width: rect.width, height: middleBottomPointYOffset) | |
| //calculate center of circle | |
| centerForCircle = CGPoint(x: rect.midX, y: edgeBottomPointYOffset - (thresholdDrag / 2)) | |
| circleLayer.frame = CGRect(x: centerForCircle.x, y: centerForCircle.y, width: 0, height: 0) | |
| //wondering why are we providing frame with height and width zero and origin to center of circle?? | |
| //since animating a layer about z axis by default rotates whole frame of that layer about its origin | |
| //so setting origin of frame of circle layer to center of circle with height and width as zero(basically a pin point \ (•◡•) /) | |
| //then applying rotation about z-axis will rotate our circle in desired way | |
| // kinda hack you want to use if you are ever stuck in these rotation stuff ¯\_(ツ)_/¯ | |
| } | |
| /// calculating starting angle to draw circle according to fraction of drag completed | |
| /// - Parameter fractionCompleted: fraction of drag completed | |
| private func getStartAngle(_ fractionCompleted : CGFloat) -> CGFloat{ | |
| return ((2 * CGFloat.pi) * (fractionCompleted)) | |
| } | |
| //MARK: - animation | |
| /// animates refresh circle | |
| private func animateRefreshCircle(){ | |
| let animation = CABasicAnimation(keyPath: "transform.rotation.z") | |
| animation.fromValue = 0.0 | |
| animation.toValue = CGFloat.pi * CGFloat(2.0) | |
| animation.duration = 1.5 | |
| animation.repeatCount = .infinity | |
| animation.fillMode = .forwards | |
| animation.isRemovedOnCompletion = false | |
| circleLayer.add(animation, forKey: "rotate") | |
| } |
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