如何使用核心绘图在方法numberForPlot中将时间作为xAxis数据值传递？ [英] how to pass time as xAxis data value in method numberForPlot using core plot?
问题描述
我需要创建心率与时间图。在xAxis中，我显示时间，格式为 HH：mm：ss，在y轴中为十进制值。我的代码如下：
I need to create graph which is "Heart rate vs time". in xAxis I am showing time which is in format of "HH:mm:ss" and at y Axis its decimal value. My code is as below :
图形的数据源：
var graphData:[(String,Double)] = []
let data = ("17:56:35",Double(65))
let data1 = ("18:04:13",Double(95))
let data2 = ("18:8:35",Double(25))
self.graphData.append(data)
self.graphData.append(data1)
self.graphData.append(data2)
设置图形并绘制数据代码：
Set up graph and plot data code:
func setGraph() {
let tts = CPTMutableTextStyle()
tts.fontSize = 75.0
tts.color = CPTColor(CGColor: UIColor.blackColor().CGColor)
tts.fontName = "HelveticaNeue-Bold"
self.graph.titleTextStyle = tts
self.graph.title = "Heart Rate vs Time"
self.graph.applyTheme(CPTTheme(named:kCPTPlainWhiteTheme))
let plotSpace = graph.defaultPlotSpace as! CPTXYPlotSpace!
plotSpace.allowsUserInteraction = false
let xRange = plotSpace.xRange.mutableCopy() as! CPTMutablePlotRange
xRange.locationDouble = Double(0)
xRange.lengthDouble = Double(1000)
plotSpace.xRange = xRange
let yRange = plotSpace.yRange.mutableCopy() as! CPTMutablePlotRange
yRange.locationDouble = Double(0)
yRange.lengthDouble = Double(210)
plotSpace.yRange = yRange
graph.addPlotSpace(plotSpace)
graph.plotAreaFrame!.paddingTop = 0
graph.plotAreaFrame!.paddingRight = 0
graph.plotAreaFrame!.paddingBottom = graphOffset
graph.plotAreaFrame!.paddingLeft = graphOffset
graph.plotAreaFrame!.masksToBorder = false
// Grid line styles
let majorLineStyle = CPTMutableLineStyle()
majorLineStyle.lineWidth = 0.75
majorLineStyle.lineColor = CPTColor.redColor()
let minorLineStyle = CPTMutableLineStyle()
minorLineStyle.lineWidth = 0.25
minorLineStyle.lineColor = CPTColor.blackColor()
//Axis Line colors
let axisLineStyle = CPTMutableLineStyle()
axisLineStyle.lineWidth = 2.0
axisLineStyle.lineColor = CPTColor.blackColor()
//Axis Label colors
let labelTextStyle = CPTMutableTextStyle()
labelTextStyle.textAlignment = CPTTextAlignment.Left
labelTextStyle.color = CPTColor.blackColor()
//Axis title color
let titleTextStyle = CPTMutableTextStyle()
titleTextStyle.textAlignment = CPTTextAlignment.Left
titleTextStyle.color = CPTColor.blackColor()
titleTextStyle.fontSize = 15
let dataSourceLinePlot = CPTScatterPlot()
let lineStyle = CPTMutableLineStyle()
lineStyle.lineWidth = 3.0
lineStyle.lineColor = CPTColor.blueColor()
dataSourceLinePlot.dataLineStyle = lineStyle
dataSourceLinePlot.identifier = kPlotIdentifier
// dataSourceLinePlot.dataSource = self
let xts = CPTMutableTextStyle()
xts.color = CPTColor(componentRed: 255.0, green: 255.0, blue: 255.0, alpha: 1.0)
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "HH:mm:ss"
let timeformatter = CPTTimeFormatter(dateFormatter: dateFormatter)
timeformatter.referenceDate = NSDate()
let axisSet = graph.axisSet as! CPTXYAxisSet!
let xAxis = axisSet.xAxis as CPTXYAxis!
xAxis.axisTitle = CPTAxisTitle(text: "Elapsed Time", textStyle: xts)
xAxis.labelFormatter = timeformatter
xAxis.majorGridLineStyle = majorLineStyle
xAxis.minorGridLineStyle = minorLineStyle
xAxis.majorIntervalLength = NSNumber(double: 60.0)
let yAxis = axisSet.yAxis as CPTXYAxis!
yAxis.axisTitle = CPTAxisTitle(text: "Heart Rate", textStyle: xts)
let axisFormatter = NSNumberFormatter()
axisFormatter.maximumFractionDigits = 0
axisFormatter.minimumIntegerDigits = 1
yAxis.labelFormatter = axisFormatter
yAxis.titleOffset = 35.0
yAxis.majorIntervalLength = 20
yAxis.majorGridLineStyle = majorLineStyle
yAxis.minorGridLineStyle = minorLineStyle
graph.addPlot(dataSourceLinePlot)
self.IBviewGraph.hostedGraph = self.graph
}
要绘制数据：
func setGraphData() {
dispatch_sync(dispatch_get_main_queue(), {
let plot = CPTScatterPlot()
plot.dataSource = self
let actualPlotStyle = plot.dataLineStyle!.mutableCopy() as! CPTMutableLineStyle
actualPlotStyle.lineWidth = 2.0
actualPlotStyle.lineColor = CPTColor(CGColor: (UIColor.yellowColor().CGColor))
plot.dataLineStyle = actualPlotStyle
plot.interpolation = .Linear
self.graph.addPlot(plot)
})
}
数据源方法
func numberOfRecordsForPlot(plot: CPTPlot) -> UInt {
return 3
}
func numberForPlot(plot: CPTPlot, field: UInt, recordIndex: UInt) -> AnyObject?{
var num = NSNumber()
let index = Int(recordIndex)
switch field {
case 0://xaxis
return graphData[index].0
case 1://yaxis
return graphData[index].1
default:
break
}
print("coordintes = ",num)
return num
}
我的图形被淹没，但只有yAxis点正确，它没有考虑xAxis值，因此，因为这些点在图形中的位置错误。我认为我在xAxis的numberForPlot方法中传递的值是错误的，但不知道如何传递它。给我一些解决方案。
My graph is drown but only yAxis points are correct , its not considering xAxis value and so because of that points are at wrong position in graph. I think the value I am passing in method numberForPlot for xAxis is wrong , but don't know how to pass it. Give me some solution.
推荐答案
graphData 数组中的x值是字符串。 Core Plot希望数据源为每个索引返回一个数值。它从时间字符串中读取小时，并将其用作x值。
The x-values in the graphData array are strings. Core Plot expects the datasource to return a numeric value for each index. It's reading the hour from the time string and using that for the x-value.
x轴配置为显示0到1,000之间的数字。因此，您需要将时间数据转换为该范围内的数字。跟踪用于格式化轴标签的参考日期（即，将其存储在实例变量中），并使用该参考日期将时间数据转换为距参考日期以秒为单位的偏移量。
The x-axis is configured to display numbers in the range 0 to 1,000. Therefore, you need to convert the time data to a number in that range. Keep track of the reference date used to format the axis labels (i.e., store it in an instance variable) and use that to convert the time data to an offset in seconds from the reference date.
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