Candlestick Chart with dates and time on x-axis - swift

Question

I am trying to create an candlestick chart using Charts Framework using with Codable as JSON passing myclass can be shown as :
struct ChartDataPair: Codable {
var DateTime: String = ""
var Open: Double = 0.0
var High: Double = 0.0
var Low: Double = 0.0
var Close: Double = 0.0
}
Which creates an array of chartDataPairs as shown :
struct ChartData: Codable {
var chartDataPairs: [ChartDataPair]
}
The value that I am fetching will be shows below a bit as example :
{"chartDataPairs":
[{
"DateTime": "2018/10/1 10:00:01",
"Open": 50.05,
"High": 50.05,
"Low": 49.00,
"Close":49.00
},
{
"DateTime": "2018/10/1 10:05:02",
"Open": 51.05,
"High": 54.06,
"Low": 40.00,
"Close":45.06
},
{
"DateTime": "2018/10/1 10:10:02",
"Open": 50.05,
"High": 64.06,
"Low": 40.00,
"Close":58.06
}]
}
The data is just a sample so just wrote 3 values. Now I have to fetch only time and convert the DateTime String to Double to plot it in x-axis of the charts. For with I m using :
var dataEntries: [ChartDataEntry] = []
guard let financialData = dataChart.self else {
return
}
for chartData in financialData{
let open = chartData.Open
let close = chartData.Close
let high = chartData.High
let low = chartData.Low
let datetime = chartData.DateTime
let formatter = DateFormatter()
formatter.dateFormat = "YYYY/MM/dd HH:mm:ss"
let yourDate = formatter.date(from: datetime)
formatter.dateFormat = "HH:mm"
let myStringafd = formatter.string(from: yourDate!)
let time = myStringafd
let components = time.characters.split { $0 == ":" } .map { (x) -> Int in return Int(String(x))! }
let hours = components[0]
let minutes = components[1]
let double1 = Double("\(hours).\(minutes)")
let dataEntry = CandleChartDataEntry(x: double1! , shadowH: high, shadowL: low, open: open, close: close)
dataEntries.append(dataEntry)
}
let chartDataSet = CandleChartDataSet(values: dataEntries, label: "")
chartDataSet.axisDependency = .left
chartDataSet.drawIconsEnabled = false
chartDataSet.shadowColor = .darkGray
chartDataSet.shadowWidth = 0.7
chartDataSet.decreasingColor = .red
chartDataSet.decreasingFilled = true // fill up the decreasing field color
chartDataSet.increasingColor = UIColor(red: 122/255, green: 242/255, blue: 84/255, alpha: 1)
chartDataSet.increasingFilled = true // fill up the increasing field color
chartDataSet.neutralColor = .blue
chartDataSet.barSpace = 1.0
chartDataSet.drawValuesEnabled = false
let chartData = CandleChartData(dataSet: chartDataSet)
candlestickView.data = chartData
I know that the conversion of the time to double ins't correct as per it is needed, Here I need some help on converting the datetime to double value.
The second issue is the bar width of the candlestick, I am unable to decrease the width of the candlestick.
And I want to fill up the x-axis with the time value like HH:MM with certain intervals like 15 mins, 50 mins, 4 hrs etc.
For which I followed few questions and suggestions here in given link below :
iOS-Charts Library: x-axis labels without backing data not showing
On this issue: candlestickView.xAxisRenderer = XAxisWeekRenderer()
isn't working. It is calling for viewporthandler, x-axis and transformation.
Though I can get the custom labels from the custom IAxisValueFormatter. The interval between the two values in the x-axis is not what I wanted it to be like in 15 mins or 50 mins or 4 hrs etc.
ios Charts 3.0 - Align x labels (dates) with plots
On the above mentioned link I am unable to get the minTimeInterval
and referenceTimeInterval
Basically What I want to do here is plot the hour and minute form the string that I am fetching from the JSON in x-axis and create a custom interval in between the values of x-axis while creating the custom x-axis labels.
My chart is currently shown as :
Candlestick Chart

Answer 1

I have same thing to display so I used this way to display the data
let xAxis = chartView.xAxis
var dataPoints = [String]()
for i in 0 ..< arrData.count
{
let timeStampFrom = arrData[i].time
dataPoints.append(self.stringFromTimestamp(timeStampFrom, strDateFormat: "h a"))
}
xAxis.valueFormatter = IndexAxisValueFormatter(values:dataPoints)
xAxis.setLabelCount(5, force: false)
Some needed function
func stringFromTimestamp(_ timeInterval : Double ,strDateFormat : String)->String
{
let dateFormatter = DateFormatter()
self.setDateFormat(dateFormatter,dateFormat: strDateFormat)
let date = Date(timeIntervalSince1970: TimeInterval(timeInterval))
return dateFormatter.string(from: date)
}
here is the output