允许 PieChartView 在 Swift 中隐藏小切片的标签

Question

我正在使用图表 iOS 框架制作图表。但当切片很小时，该值将覆盖。我怎样才能隐藏它？这个问题和这个GitHub link类似，但是我不明白它是如何工作的。我是否只需要在我的视图控制器中添加代码或将 PieChartRenderer.swift 文件拖到我的项目中？

有人可以向我解释如何使用拉取请求或一些开放的 public 功能...

抱歉，我是 iOS 框架的新手。

这是我的代码。

@IBOutlet weak var myChart: PieChartView!

var valueColors = [UIColor]()
var dataEntries = [PieChartDataEntry]()
var record = [Record]()
var category = [String]()
var categoryTotal : [Double] = []
var categoryArray : [String] = []

func setDataCount() {
    valueAndColor()

    let set = PieChartDataSet(values: dataEntries, label: nil)

    set.colors = valueColors
    set.valueLinePart1OffsetPercentage = 0.8
    set.valueLinePart1Length = 0.2
    set.valueLinePart2Length = 0.4
    set.xValuePosition = .outsideSlice
    set.yValuePosition = .outsideSlice
    set.selectionShift = 0.0

    let data = PieChartData(dataSet: set)
    let Formatter:ChartFormatter = ChartFormatter()
    data.setValueFormatter(Formatter)
    data.setValueFont(.systemFont(ofSize: 11, weight: .light))
    data.setValueTextColor(.black)

    myChart.data = data
    myChart.highlightValues(nil)
}

func setup(pieChartView chartView: PieChartView) {
    chartView.usePercentValuesEnabled = true
    chartView.drawSlicesUnderHoleEnabled = true
    chartView.holeRadiusPercent = 0.58
    chartView.chartDescription?.enabled = false
    chartView.drawCenterTextEnabled = true
    chartView.centerAttributedText = attributedString;
    chartView.drawHoleEnabled = true
    chartView.rotationAngle = 0
    chartView.rotationEnabled = true
    chartView.highlightPerTapEnabled = true
}

func valueAndColor(){
    for i in 0..<categoryArray.count{
        let dataEntry = PieChartDataEntry(value: categoryTotal[i], label: categoryArray[i % categoryArray.count])
        dataEntries.append(dataEntry)

        if categoryArray[i] == "吃喝" {
            valueColors.append(UIColor.yellow)
        }else if categoryArray[i] == "交通"{
            valueColors.append(UIColor.red)
        }...
 }

Answer 1

创建一个自定义格式化程序，我将minNumber设置为10.0，当值小于minNumber时返回空字符串，否则返回值。

public class ChartFormatter: NSObject, IValueFormatter{

    public func stringForValue(_ value: Double, entry: ChartDataEntry, dataSetIndex: Int, viewPortHandler: ViewPortHandler?) -> String {

        let total = UserDefaults.standard.double(forKey: "totalValue")

        var valueToUse = value/total * 100
        valueToUse = Double(round(10*valueToUse)/10)
        print("valueToUse: \(valueToUse)")
        let minNumber = 10.0

        if(valueToUse<minNumber) {
            return ""
        }
        else {
            return String(valueToUse) + "%"
        }
    }

}

然后确保设置 totalValue 变量，将其存储在 UserDefaults 中（以便可以在格式化程序中访问它）并为图表设置格式化程序

    var totalValue = 0.0

    let units = [10.0, 4.0, 6.0, 3.0, 12.0, 16.0]
    for a in units {
        totalValue += a
    }
    UserDefaults.standard.set(totalValue, forKey: "totalValue")

    let formatter:ChartFormatter = ChartFormatter()

    data.setValueFormatter(formatter)

结果：

Answer 2

较新版本的 Charts 库添加了此功能并使其变得简单属性以在 PieChartView:

的实例上设置

pieChart.sliceTextDrawingThreshold = 20

sliceTextDrawingThreshold 属性设置绘制标签所需的最小角度。

允许 PieChartView 在 Swift 中隐藏小切片的标签

Allow PieChartView to hide labels for tiny slices in Swift

swift

ios-charts