设置自定义数据集值 - 图表3.0.4和使用Swift 4.0

Question

我想在图形点中显示(1,2,3,4,5,6)位置的一些随机值,如(16,23,323,63,8,66).我在图表框架中使用折线图.

是否有任何格式化程序可以完成这项工作？

上图显示了我想要绘制的示例图.

Answer 1

创建自定义格式化程序：

class RandomCustomFormatter: NSObject, IValueFormatter {

    convenience init(lineChart: LineChartView, xArray: [Double], yArray: [Double]) {
        self.init()

        var y = yArray
        y.shuffle(count: y.count)
        var dataEntries = [ChartDataEntry]()
        var c = 0
        for _ in xArray {
        dataEntries.append(ChartDataEntry(x: xArray[c], y: y[c]))
        c+=1
        }
        let theDataSet = LineChartDataSet(values: dataEntries, label: "Test Data")
        print("dataentries shuffled: \(dataEntries)")

        lineChart.data = LineChartData(dataSet: theDataSet)


    }


    public func stringForValue(_ value: Double, entry: ChartDataEntry, dataSetIndex: Int, viewPortHandler: ViewPortHandler?) -> String {
        let valueToUse = Int(value)
        print("valuetouse: \(valueToUse)")
        return String(valueToUse)
    }
}

添加数组扩展：

extension Array {
    mutating func shuffle(count: Int) {
        for _ in 0...count-1 {
            sort { (_,_) in arc4random() < arc4random() }
        }
    }
}

设置格式化程序：

//x datapoints
let x = [1.0,2.0,3.0,4.0,5.0,6.0]
//y datapoints
var y = [8.0,16.0,23.0,63.0,66.0,323.0]
let formatter = RandomCustomFormatter(lineChart: lineChart, xArray: x, yArray: y)
self.lineChart?.data?.setValueFormatter(formatter)

结果1：

结果2：