Swift IOS 图表 - 堆积条形图

Question

我正在尝试使用 iOS Chart 设置一个简单的堆积条形图。

所有示例都显示了数据循环 - 我只想将一个条目直接写入代码中。

https://github.com/danielgindi/Charts/blob/master/ChartsDemo-iOS/Swift/Demos/StackedBarChartViewController.swift

我崩溃了:let set = BarChartDataSet。

错误是:

Cannot convert value of type 'BarChartDataEntry' to expected argument type '[ChartDataEntry]?'

    func _costChart( comm: Double, margin: Double, expense: Double) {

        let yVals = BarChartDataEntry(x: 0.0, yValues: [comm, margin, expense ], icon: #imageLiteral(resourceName: "icon"))

        let set = BarChartDataSet(entries: yVals, label: "")

        let data = BarChartData(dataSets: set)

        costChart.data = data
}

如何编写此内容以确认格式正确？

Answer 1

BarChartDataSet 需要一个可为 null 的 ChartDataEntry 数组。所以如果你想设置数据，你需要传递nil或者一个数组。

func _costChart( comm: Double, margin: Double, expense: Double) {

   let yVals = BarChartDataEntry(x: 0.0, yValues: [comm, margin, expense ], icon: #imageLiteral(resourceName: "icon"))

   let set = BarChartDataSet(entries: [yVals], label: "") // Passing array to entries instead of just the BarChartDataEntry (just a single item)

   let data = BarChartData(dataSets: set)

   costChart.data = data 

}