Trying to enter Date/String in ChartDataEntry

I am trying to add a Date/String as the xAxis labels in Charts (needs to have equal space in between labels)

I am doing below but the x in the constructor only expects a double.

Any idea?

for i in 0..<self.grahEntries.count {
     let x1 = self.grahEntries[i].x
     let dateFormatter = DateFormatter()
     dateFormatter.dateFormat = "YYY-MM-DD HH:mm:ss"
     let date = dateFormatter.date(from: x1)
     print(date)
     let dataEntry = ChartDataEntry(x: date, y: self.grahEntries[i].y)//HERE IS MY PROBLEM!! xAxis is only double
     dataEntries.append(dataEntry)
}

 let line1 = LineChartDataSet(values: dataEntries, label: "Units Consumed")
    line1.colors = [NSUIColor.blue]
    line1.mode = .cubicBezier
    line1.cubicIntensity = 0.2


    let gradient = getGradientFilling()
    line1.fill = Fill.fillWithLinearGradient(gradient, angle: 90.0)
    line1.drawFilledEnabled = true

    let data = LineChartData()
    data.addDataSet(line1)
    mChart.data = data
    mChart.setScaleEnabled(false)
    mChart.animate(xAxisDuration: 1.5)

    mChart.xAxis.valueFormatter = DateAxisValueFormatter()
    mChart.xAxis.granularity = 1.0


    mChart.drawGridBackgroundEnabled = false
    mChart.xAxis.drawAxisLineEnabled = false
    mChart.xAxis.drawGridLinesEnabled = false
    mChart.leftAxis.drawAxisLineEnabled = true
    mChart.leftAxis.drawGridLinesEnabled = true
    mChart.rightAxis.drawAxisLineEnabled = false
    mChart.rightAxis.drawGridLinesEnabled = false
    mChart.legend.enabled = false
    mChart.xAxis.enabled = true
    mChart.leftAxis.enabled = true
    mChart.rightAxis.enabled = false

    mChart.xAxis.labelPosition = .bottom

    mChart.xAxis.drawLabelsEnabled = true
    mChart.xAxis.drawLimitLinesBehindDataEnabled = true
    mChart.xAxis.avoidFirstLastClippingEnabled = true

UPDATE :

I did as @ces said its spreading them accurately but I still cant see labels. I updated my code above to show table

If you want the data to be spaced evenly (i.e. not representing an accurate timeline) then the answer is simpler.

Change your for loop to

var dates: [String] = []
for i in 0..<self.grahEntries.count {
     let x1 = self.grahEntries[i].x
     let dateFormatter = DateFormatter()
     dateFormatter.dateFormat = "YYY-MM-DD HH:mm:ss"
     let date = dateFormatter.date(from: x1)
     dates.append(date)
     let dataEntry = ChartDataEntry(x: Double(i), y: self.grahEntries[i].y)
     dataEntries.append(dataEntry)
}

and change

mChart.xAxis.valueFormatter = DateAxisValueFormatter(dates)

Then change DataAxisValueFormatter to accept an array of strings in the constructor and store them. Change

func stringForValue(_ value: Double, axis: AxisBase?) -> String
{
    let i = Int(value)
    return dates[i]
}