swift - 图例是否限制标题的数量？

Question

我正在使用 iso-charts 尝试在 iOS 应用程序中绘制饼图。

无论我尝试什么，我似乎都无法在图例中绘制完整的标题数。

我的数据设置为:

ages = ["18-", "25-", "35-", "45-", "55-", "65-", "75+"]
agePercentages = [10.0, 20.0, 30.0, 5.0, 10.0, 45.0, 120.0]

我将饼图设置为的代码:

func setPieDefaults(myPieChart: PieChartView) -> PieChartView {

    myPieChart.frame = CGRectMake(0, 0, UIScreen.mainScreen().bounds.size.width, UIScreen.mainScreen().bounds.size.width*0.5)
    myPieChart.usePercentValuesEnabled = true
    myPieChart.holeTransparent = true
    myPieChart.holeColor = UIColor.darkPurpleColor()
    myPieChart.backgroundColor = UIColor.darkPurpleColor()
    myPieChart.rotationAngle = 0.0
    myPieChart.rotationEnabled = true
    myPieChart.centerTextFont = UIFont(name: "HelveticaNeue-Bold", size:20)!
    myPieChart.descriptionText = ""
    myPieChart.centerText = "%"
    myPieChart.centerTextColor = UIColor.whiteColor()
    myPieChart.drawHoleEnabled = true
    myPieChart.noDataText = "Loading Data ..."
    let legend = myPieChart.legend
    legend.font = UIFont(name: "Arial", size: 11)!
    legend.textColor = UIColor.whiteColor()
    legend.position = .RightOfChart
    legend.form = .Circle

    return myPieChart
}

还有..

func setChart(dataPoints: [String], values: [Double], myPieView: PieChartView) {

    var dataEntries: [ChartDataEntry] = []

    for i in 0..<dataPoints.count {
        let dataEntry = ChartDataEntry(value: values[i], xIndex: i)
        dataEntries.append(dataEntry)
    }

    var colors = [UIColor]()
    switch myPieView {
    case genderPieChartView:
        colors = [UIColor.blueColor(), UIColor.pinkColor()]
    default:
        colors = ChartColorTemplates.colorful()
    }

    let pieChartDataSet = PieChartDataSet(yVals: dataEntries, label: nil)
    pieChartDataSet.sliceSpace = 3.0
    pieChartDataSet.colors = colors

    let pieChartData = PieChartData(xVals: dataPoints, dataSet: pieChartDataSet)
    myPieView.animate(xAxisDuration: 2, yAxisDuration: 2)

    let pFormatter = NSNumberFormatter()
    pFormatter.numberStyle = .PercentStyle
    pFormatter.maximumFractionDigits = 0
    pFormatter.percentSymbol = ""
    pFormatter.multiplier = 1
    pieChartData.setValueFormatter(pFormatter)
    pieChartData.setValueFont(UIFont(name: "HelveticaNeue-Bold", size: 11)!)
    pieChartData.setValueTextColor(UIColor.whiteColor())

    myPieView.data = pieChartData
    myPieView.drawSliceTextEnabled = false

}

但它不会打印超过 5 个标签。它完美地返回了馅饼切片。但不是图例中的标签。

我做错了什么吗？预先感谢您告知我。

Answer 1

已解决。

在阅读framework docs对于Android版本好一点:

The number of entries the automatically generated legend contains depends on the number of different colors (across all DataSet objects) as well as on the DataSet labels. The labels of the Legend depend on the labels set for the used DataSet objects in the chart. If no labels for the DataSet objects have been specified, the chart will automatically generate them. If multiple colors are used for one DataSet, those colors are grouped and only described by one label.

我意识到我需要增加 ChartColorTemplate.colorful() 定义中的颜色数量以匹配我尝试使用的标签数量。当前示例代码仅定义了 5 种颜色。

public class func colorful () -> [UIColor]
{
    return [
        UIColor(red: 193/255.0, green: 37/255.0, blue: 82/255.0, alpha: 1.0),
        UIColor(red: 255/255.0, green: 102/255.0, blue: 0/255.0, alpha: 1.0),
        UIColor(red: 245/255.0, green: 199/255.0, blue: 0/255.0, alpha: 1.0),
        UIColor(red: 106/255.0, green: 150/255.0, blue: 31/255.0, alpha: 1.0),
        UIColor(red: 179/255.0, green: 100/255.0, blue: 53/255.0, alpha: 1.0),
        UIColor(red: 200/255.0, green: 100/255.0, blue: 53/255.0, alpha: 1.0), // added colour
        UIColor(red: 150/255.0, green: 150/255.0, blue: 70/255.0, alpha: 1.0), // added colour
        UIColor(red: 84/255.0, green: 78/255.0, blue: 53/255.0, alpha: 1.0), // added colour
    ]
}

如果你有同样的问题，那就定义更多的颜色来满足最大标签数量的需求。如果您尝试对图例进行自动换行(我也遇到过)，这也会解决一个问题。