Display label MMyyyy for barChart

[perwyl]

Hi

I need to display the bar chart data according to MMyyyy, may i know how should i approach this?

I tried converting the Date to double using expirationDate.timeIntervalSinceDate and convert it back to date at func stringForValue(_ value: Double, axis: AxisBase?) -> String {}

The barData's color is gone. I can see it's top label value though

Some Observations as well:
let yData = BarChartDataEntry(x: month, y: value) //month = 1475 251 200

func stringForValue(_ value: Double, axis: AxisBase?) -> String { } //value = 1464 000 000 and increment by 2 000 000

[DoctorG]

Same issue here. Hope this objective-c code from my app helps you out.

I think what you want to do is implement IAxisValueFormatter delegate.

@interface UndeliveredGraphDueByMonthViewController: UIViewController <ChartViewDelegate, IChartAxisValueFormatter>

I stored my xLabels as an array of dates but discovered the delegate was calling for items out of the array bounds and crashing the program, so I ended up using a starting date and implanting a function I otherwise use to add months to the start month/year for the graph.

Here is my chart setup for xAxis:
ChartXAxis *xAxis = self.chartView.xAxis;
xAxis.labelPosition = XAxisLabelPositionBottom;
xAxis.axisMinimum = -0.5; //subtract 0.5 to show all of first bar
//set axismax after counting xLabels
xAxis.granularity = 1.0;
xAxis.centerAxisLabelsEnabled = YES;
xAxis.labelRotationAngle = -45;
xAxis.valueFormatter = self; //IAxisformatter

Here's the delegate callback:

#pragma mark - IAxisValueFormatter

• (NSString *)stringForValue:(double)value axis:(ChartAxisBase *)axis {
  NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
  [dateFormatter setDateFormat:[NSDateFormatter dateFormatFromTemplate:@"MMMyyyy" options:0 locale:[NSLocale currentLocale]]];
  NSDate *startMY = xLabels[0]; //first date for xValues
  NSDate *currentMY = [AppDelegate addMonthsToDate:startMY monthsToAdd:value];
  NSString *retDate = [dateFormatter stringFromDate:currentMY];
  NSLog(@"value: %f date:%@", value,retDate);
  return retDate;
  }

Heres my add month function incase you need it:
+(NSDate *)addMonthsToDate:(NSDate *)referenceDate monthsToAdd:(long)months {
NSDate *nextMonth = nil;

if (referenceDate) {
	NSCalendar *gregorian = [[NSCalendar alloc]initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
	NSDateComponents *offsetComponents = [[NSDateComponents alloc]init];

	[offsetComponents setMonth:months];
	nextMonth = [gregorian dateByAddingComponents:offsetComponents toDate:referenceDate options:0];
}
return (nextMonth);

}

[st-small]

@DoctorG Thank you for example! I'm working with it but can't do that I want, can you help me?! I have array with NSDate objects and I want to show them in xAxis. When I use [yVals addObject:[[BarChartDataEntry alloc] initWithX:x y:val]]; I use double parameter something like (NSTimeInterval tInt = [[NSDate date] timeIntervalSinceDate:self.dates[i]];), but when I want to get string from my x value, using delegate IAxisValueFormatter, it shows another date that I need...

Please, need in your help! TNX!

[liuxuan30]

@st-small it's about data formatter issues, so maybe ask on SO and be more specific.
As I see you get the interval, as long as you pass the write value, it can't be too diferent dates..

[st-small]

@liuxuan30 Thank you for reply! I did it! It was very simple! In method setChart... I use int i with steps 0,1,2,...n and in formatter method I use my dates and make strings from them to show as labels in xAxis. But have question, can I show yAxis values in format integer value, without .00? I want to see value, for example, 7, but now showing 7.00. Tnx!

Update: just now see your reply in other thread about valueformatter, ok, will try to have that I want, thank you very much!!!