我创建了一个 UIView 的子类,我在其中绘制了一个图形。我将它设为公共(public)类,这样我就可以向它传递新数据并在需要时更新它。
在我升级到 Xcode 6.3/Swift 1.2 之前,一切都运行良好。现在,当该 View 尝试呈现我的应用程序崩溃时。
我得到的错误是:
Assertion failed: (CGFloatIsValid(x) && CGFloatIsValid(y)), function void CGPathMoveToPoint(CGMutablePathRef, const CGAffineTransform *, CGFloat, CGFloat), file Paths/CGPath.cc, line 254.
这是我的类(class)代码:
import UIKit
public class GraphView: UIView {
//Data from parent VC
var graphPoints = [0, 0, 0, 0, 0, 0, 0]
var keyColor = BabyMasterStyleKit.bathsBase
override public func drawRect(rect: CGRect) {
let context = UIGraphicsGetCurrentContext()
let colorSpace = CGColorSpaceCreateDeviceRGB()
let width = rect.width
let height = rect.height
//calculate the x point
let margin:CGFloat = 15.0
var columnXPoint = { (column:Int) -> CGFloat in
//Calculate gap between points
let spacer = (width - margin*2 - 4) /
CGFloat((self.graphPoints.count - 1))
var x:CGFloat = CGFloat(column) * spacer
x += margin + 2
return x
}
// calculate the y point
let topBorder:CGFloat = 15
let bottomBorder:CGFloat = 15
let graphHeight = height - topBorder - bottomBorder
let maxValue = maxElement(graphPoints)
var columnYPoint = { (graphPoint:Int) -> CGFloat in
var y:CGFloat = CGFloat(graphPoint) /
CGFloat(maxValue) * graphHeight
y = graphHeight + topBorder - y // Flip the graph
return y
}
//Draw horizontal graph lines on the top of everything
var linePath = UIBezierPath()
//top line
linePath.moveToPoint(CGPoint(x:0, y: topBorder))
linePath.addLineToPoint(CGPoint(x: width,
y:topBorder))
//center line
linePath.moveToPoint(CGPoint(x:0,
y: graphHeight/2 + topBorder))
linePath.addLineToPoint(CGPoint(x:width,
y:graphHeight/2 + topBorder))
let color = UIColor.lightGrayColor()
color.setStroke()
linePath.lineWidth = 0.5
linePath.stroke()
// draw the line graph
keyColor.setFill()
keyColor.setStroke()
// set up the points line
var graphPath = UIBezierPath()
// go to start of line
graphPath.moveToPoint(CGPoint(x:columnXPoint(0), y:columnYPoint(graphPoints[0])))
// add points for each item in the graph points array
// at the correct (x, y) for the point
for i in 1..<graphPoints.count {
let nextPoint = CGPoint(x:columnXPoint(i),
y:columnYPoint(graphPoints[i]))
graphPath.addLineToPoint(nextPoint)
}
graphPath.stroke()
//Draw the circles on top of graph stroke
for i in 0..<graphPoints.count {
var point = CGPoint(x:columnXPoint(i), y:columnYPoint(graphPoints[i]))
point.x -= 5.0/2
point.y -= 5.0/2
let circle = UIBezierPath(ovalInRect:
CGRect(origin: point,
size: CGSize(width: 6.0, height: 6.0)))
circle.fill()
}
// add left and bottom borders
UIColor.lightGrayColor().setStroke()
var borderPath = UIBezierPath()
borderPath.moveToPoint(CGPoint(x:0, y:0))
borderPath.addLineToPoint(CGPoint(x:0, y:height))
borderPath.addLineToPoint(CGPoint(x:width, y:height))
borderPath.stroke()
}
}
应用在这一行失败:
graphPath.moveToPoint(CGPoint(x:columnXPoint(0), y:columnYPoint(graphPoints[0])))
数组 graphPoints
是我传入的数据。我将其默认设置为全 0。在我的 ViewController 中,我有一个函数,它传入一组真实数据(7 个不同的数字),然后执行 setNeedsDislay()
以根据需要重新呈现 View 。
感谢您的帮助。
最佳答案
当输入数组为
var graphPoints = [0, 0, 0, 0, 0, 0, 0]
然后
let maxValue = maxElement(graphPoints)
使 maxValue
为 0,因此 columnYpoint
中的行
var y:CGFloat = CGFloat(graphPoint) / CGFloat(maxValue) * graphHeight
除以零并使 y
成为 NaN
。这是初始数组中所有元素为零的特殊情况。
关于ios - 升级到 Swift 1.2/Xcode 6.3 后 moveToPoint 失败,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/29563862/