Charts: Convert x value labels to String? from Double? [Horizontal Barchart] (Swift v3)

[sree127]

I'm not able to figure out how to convert the x value labels to String?

Is it possible to convert the values to ["Jan", "Feb", "Mar"] instead of [1, 2, 3].. ?

[Huang-Libo]

@sree127 You can use NSTimeInterval to store date, then use a formatter to custom it.
Also you can search NSTimeInterval at issue, you will get more info about this.

[sree127]

Hi @Huang-Libo. Thanks for replying. Can xaxis values take any String values? There are no examples in demo on how to use IAxisValueFormatter . Can you please help me with that? The data I'd be displaying will be dynamic strings. Thanks a lot

[Huang-Libo]

@sree127

1. xAxis can only store double value, as Daniel @danielgindi said before, with a formatter, a double value can present any type of thing .
2. You can look at "Time Line Chart" In Demo:-)

[sree127]

Thanks a lot @Huang-Libo. That was easier than I'd thought :-)

[jayvenn]

This is what I spent a lot of time trying to figure out. I used a website to convert obj-c code to swift. Still can't get any of it to work properly. All I want is A, B, C, D on the xAxis. Thanks in advance to helpers.

`import UIKit
import Charts

class ViewController: UIViewController, ChartViewDelegate {

@IBOutlet weak var barChartView: BarChartView!

var dataEntries: [BarChartDataEntry] = []

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    barChartView.delegate = self
    barChartView.drawGridBackgroundEnabled = false
    barChartView.legend.enabled = false
    barChartView.isUserInteractionEnabled = false
    barChartView.rightAxis.enabled = false
    barChartView.drawValueAboveBarEnabled = true

    let xAxis = barChartView.xAxis
    xAxis.drawGridLinesEnabled = false
    xAxis.valueFormatter = DateValueFormatter()

    let yAxis = barChartView.leftAxis
    yAxis.drawGridLinesEnabled = false


    var yValues: [Double] = [2, 3, 1, 3, 4]
    var xValues: [String] = ["A", "B", "C", "D"]

    self.setDataCount(count: 4, range: 30.0)
}

func setDataCount(count: Int, range: Double) {
    var now = Date().timeIntervalSince1970
    var hourSeconds = 3600.0
    var values = [ChartDataEntry]()
    var from = now - (Double(count) / 2.0) * hourSeconds
    var to = now + (Double(count) / 2.0) * hourSeconds

    var x = from
    while x < to {
        var y: Double = Double(arc4random_uniform(UInt32(range)))
        values.append(ChartDataEntry(x: x, y: y))
        x += hourSeconds
    }
    var set1: BarChartDataSet? = nil

    if (barChartView.data?.dataSetCount)! > 0 {
        set1 = (barChartView.data?.dataSets[0] as! BarChartDataSet)
        set1!.values = values as! [ChartDataEntry]

        barChartView.notifyDataSetChanged()
    } else {
        set1 = BarChartDataSet(values: values, label: "data set 1")

        set1!.valueTextColor = UIColor(red: 51 / 255.0, green: 181 / 255.0, blue: 229 / 255.0, alpha: 1.0)
        set1!.drawValuesEnabled = false
        set1!.highlightColor = UIColor(red: 224 / 255.0, green: 117 / 255.0, blue: 117 / 255.0, alpha: 1.0)
        var dataSets = [IChartDataSet]()
        dataSets.append(set1!)

        var data = BarChartData(dataSets: dataSets)
        self.barChartView.data = data
    }
}

}`

[sree127]

Hey @nhantrivinh, you're setting the xAxis.valueFormatter wrong. You can use the IAxisValueFormatter to change the values. Here is what I've used 👍

class ChartStringFormatter: NSObject, IAxisValueFormatter {

    var nameValues: [String]! =  ["A", "B", "C", "D"]

    public func stringForValue(_ value: Double, axis: AxisBase?) -> String {
        return String(describing: nameValues[Int(value)])
    }
}

And while setting the data :

let formatter = ChartStringFormatter()
 xAxis.valueFormatter = formatter

[tuantmdev]

@nhantrivinh use the code that @sree127 provided above and dont forget to set granularity = 1

[jorgemauricio]

@tuantmdev What if I generate the string on the go, or outside the class?

[tuantmdev]

@jorgemauricio Pass the name values as a property of the Formatter

var formatter = ChartStringFormatter()
formatter.nameValues = ["A", "B", "C", "D"] //anything you want
xAxis.valueFormatter = formatter
xAxis.granularity = 1

Just remember set formatter before set chartView.data = data of chartView

[Carielle]

Can anyone help me? I tried to follow the ChartsDemo example and the suggestions here, but my horizontal bar chart is still coming out wrong. I'll include my code, basically I'm trying to label each bar with a bit of text, but I'm getting labels on the gridlines instead of one label for each bar.

To set up the chart...

` double barWidth = 6.0;
double spaceForBar = 7.0;

dataList = dataPoints;

barChartView.noDataText = @"You need to provide data for the chart.";

[barChartView animateWithYAxisDuration:1.0];

barChartView.doubleTapToZoomEnabled = NO;
barChartView.pinchZoomEnabled = NO;
barChartView.scaleXEnabled = NO;
barChartView.scaleYEnabled = NO;

barChartView.descriptionText = @"";
//barChartView.descriptionText = unit;
NSLog(@"%@", unit);

ChartXAxis *xAxis = barChartView.xAxis;
xAxis.granularity = 1.0;
xAxis.valueFormatter = self;

barChartView.xAxis.labelPosition = XAxisLabelPositionBottom;

barChartView.leftAxis.labelCount = 4;
barChartView.leftAxis.axisMinValue = 0;

barChartView.rightAxis.labelCount = 4;
barChartView.rightAxis.axisMinValue = 0;

barChartView.extraBottomOffset = 30.0;
barChartView.legend.enabled = false;
barChartView.fitBars = YES;

NSMutableArray *dataEntries =[[NSMutableArray alloc] init];

for (int i = 0; i < count; i++)
{
    NSNumber *value = [values objectAtIndex:i];
    NSString *car_model = [dataPoints objectAtIndex:i];
    NSLog(@"%@",car_model);
    // Need to put car model in as x "value"
    BarChartDataEntry *dataEntry = [[BarChartDataEntry alloc] initWithX:i*spaceForBar y:[value doubleValue]];
    [dataEntries addObject:dataEntry];
    NSLog(@"%d", i);
}

BarChartDataSet *chartDataSet = [[BarChartDataSet alloc] initWithValues:dataEntries];
NSMutableArray *colorSet = [self getColorSet:chartDataSet :isGreenHigh];

chartDataSet.colors = colorSet;

NSMutableArray *dataSets = [[NSMutableArray alloc] init];
[dataSets addObject:chartDataSet];
BarChartData *chartData = [[BarChartData alloc] initWithDataSets:dataSets];
chartData.barWidth = barWidth;

//BarChartData *chartData = [[BarChartData alloc] initWithXVals:dataPoints dataSets:dataSets];
barChartView.data = chartData;
barChartView.data.highlightEnabled = NO;

`

My stringForValue function where dataList is my NSArray of label strings...

`- (NSString *)stringForValue:(double)value
axis:(ChartAxisBase *)axis
{
NSString *string;
string = dataList[(int)value % dataList.count];
return string;

}`

And this is what my chart looks like...

[tuantmdev]

@Carielle
The value of x you pass when init BarChartDataEntry should be the same the value of formatter method

- (NSString *)stringForValue:(double)value axis:(ChartAxisBase *)axis

In your case, i think it should change to

BarChartDataEntry *dataEntry = [[BarChartDataEntry alloc] initWithX:i y:[value doubleValue]];

[goel232]

@Carielle
@tuantmdev
@sree127
can any of you can help me with this in swift 2 ??
http://stackoverflow.com/questions/41979926/how-to-achieve-trackball-and-access-label-above-bar-on-bar-charts-in-swift-3x

[venkatesh613]

hi everyone
how to change bar values to int values
in bar chart showing 61.5 like this
In above bar chart
please help me

[ClarissaW]

@sree127
Hi, can you tell me how you can position your value labels inside of bars? Is there a property that can achieve that? BTW, thanks for asking the question you mentioned here. I met the same issue but got fixed here.