Android Question [solved] YX-chart with formatted timestamps in x-axis

[fredo]

This is regarding Klaus's "xChart": https://www.b4x.com/android/forum/threads/b4x-xui-xchart-class-and-b4xlib.91830/

I want to create a chart that displays two data series simultaneously.


The problem is the labeling of the X-axis in a YX-chart.

The source data have a timestamp in the format long as X-value.
The X values of the two data series can be different.

In order to achieve the desired result, the X-axis labels must be specified in the format "dd.mm.yyyy".

How can this be done?


Testproject attached

 

[klaus]

Sorry, but this cannot be done with an YX_Chart.
In YX_Charts, the X axis values are doubles and are treated as numeric values.

It can be made with a LINE chart and MissingDataValues.
You need to use xChart1.AddLineMultiplePoints.
When you have missing data set its value to xChart1.AddLineMultiplePoints.
Attached a modified version of your project.
I used -1 for the MissingDataValue, up to you to set any value you want.
I removed the xChart properties settings to the Designer.

On the first time stamp there is no value in the red line, the line begins on the second time stamp.
On the second time stamp there is no value in the other line, no circle drawn at the second time stamp.

 

[fredo]

...It can be made with a LINE chart and MissingDataValues.
You need to use xChart1.AddLineMultiplePoints. ...

Thank you. That is a great solution.

 

[Mahares]

hank you. That is a great solution.

Shouldn't you date format be: DateTime.DateFormat = "dd.MM.yyyy" instead of DateTime.DateFormat = "dd.mm.yyyy". Otherwise, the x axis dates don't make much sense. Or is that by design

 

[fredo]

Shouldn't you date format be: DateTime.DateFormat = "dd.MM.yyyy" instead of DateTime.DateFormat = "dd.mm.yyyy". Otherwise, the x axis dates don't make much sense. Or is that by design

Nice catch. You're right. I made an honest mistake.

 

[klaus]

Shouldn't you date format be: DateTime.DateFormat = "dd.MM.yyyy" instead of DateTime.DateFormat = "dd.mm.yyyy".

Sure, thank you !
Project in post #2 has been updated.