如何设置xAxis标签以使用图表显示间隔为1天或一周的日期？显示yAxis值时也会出现问题

Question

条形图的代码如下所示：

    override func viewDidLoad() {
        super.viewDidLoad()

        IBviewGarph.delegate = self

        months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
        let unitsSold = [1200.0, 1400.0, 600.0, 3500.0, 1200.0, 1600.0, 1400.0, 1800.0, 1200.0, 1400.0, 1500.0, 1400.0]

        setChart(months, values: unitsSold)
    }
func setChart(dataPoints: [String], values: [Double]) {

        IBviewGarph.leftAxis.axisMinValue = 500
        IBviewGarph.leftAxis.axisMaxValue = 3500

        var dataEntries: [BarChartDataEntry] = []

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

        let chartDataSet = BarChartDataSet(yVals: dataEntries, label: "Units Sold")
        let chartData = BarChartData(xVals: months, dataSet: chartDataSet)

        IBviewGarph.data = chartData
        IBviewGarph.descriptionText = ""
        chartDataSet.colors = [UIColor(red: 230/255, green: 126/255, blue: 34/255, alpha: 1)]
        IBviewGarph.xAxis.labelPosition = .Bottom
        IBviewGarph.rightAxis.drawLabelsEnabled = false
        IBviewGarph.animate(xAxisDuration: 2.0, yAxisDuration: 2.0)

    }

问题就是你可以看到图像，yAxis显示2行，不知道是什么问题，我也想设置xAxis标签来显示日期Ex：＆＃34; 28/8/2016＆＃34;间隔为1天或1周，如何将自定义标签传递给xAx，就像我为yAxis所做的一样？可能是类似的问题：Chart - Controlling axis interval, spacing and visibility但是我不知道如何处理我的问题，因为我只是简单地输入数字