Android Question How do I draw graphics?

You need to give some more detailed explanations on what exactly you want to do.

According to the data from the text every 10 seconds

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What kind of text?
What kind of data?
Where does it come from?
How many data on the chart?

Check out this tutorial from Erel:
https://www.b4x.com/etp.html?vimeography_gallery=1&vimeography_video=256408897

In fact I would recommend you watch all Erel's tutorials.

klaus said:

You need to give some more detailed explanations on what exactly you want to do.


What kind of text?
What kind of datea?
Where does it come from?
How many data on the chart?

Click to expand...

Hi Klaus,
The X axis shows time. The y-axis shows numerical data. I want to draw the graph dynamically according to the data from every second. Incoming data are numeric values that I get from an array. I have studied samples and libraries but have become thoroughly confused.

Erel's tutorials are good.

You may have a look at the xChart class / b4xlibrary.
You can add line points dynamically, there is an example in the demo program.

klaus said:

You may have a look at the xChart class / b4xlibrary.
You can add line points dynamically, there is an example in the demo program.

Click to expand...

I'm getting an error in the library installation.
Jar file not found.

Make sure to have B4A 8.8+

Erel said:

Starting with B4A (8.80), B4i (v5.50) and B4J (v7.00), a new type of libraries is available - b4x libraries.

Click to expand...

I'm using B4A 8.5

I'm getting an error in the library installation.

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How did you do it?
Without knowing what you have done it's impossible to give a concrete advice.

You have two possibilties:
1. Use the class, the xChart.bas file, add it with Project/Add Existing Modules. This works with older B4A versions.
2. Use the xChart.b4xlib, you must add it in the AdditionalLibraries folder, don't add the xChart.xml file. This works only for B4A 8.80+.
If you have B4A 9.00, then you should redefine the AdditionalLibraries folder, have a look HERE to see how to do it.

I get an error like that. I do not understand why?
Error description: xChart has been defined twice. You must remove the library reference or code module.

Itila Tumer said:

I get an error like that. I do not understand why?
Error description: xChart has been defined twice. You must remove the library reference or code module.

Click to expand...

Either use the Class in your project OR the Library. Not both at the same time.

DonManfred said:

Either use the Class in your project OR the Library. Not both at the same time.

Click to expand...

Class I want to use. I get the error when I run the application in debug mode.

Post errors as TEXT Please!

DonManfred said:

Post errors as TEXT Please!

Click to expand...

Error occurred on line: 1027 (xChart)
java.lang.NumberFormatException: Invalid double: "null"
at java.lang.StringToReal.invalidReal(StringToReal.java:63)
at java.lang.StringToReal.parseDouble(StringToReal.java:269)
at java.lang.Double.parseDouble(Double.java:295)
at b4a.xChartsDemo.xchart._getscalemant(xchart.java:2081)
at b4a.xChartsDemo.xchart._calcscaleauto(xchart.java:1596)
at b4a.xChartsDemo.xchart._initchart(xchart.java:3990)
at b4a.xChartsDemo.xchart._drawchart(xchart.java:482)
at b4a.xChartsDemo.main._createlinechart1data(main.java:547)
at b4a.xChartsDemo.main._activity_create(main.java:403)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:351)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
at b4a.xChartsDemo.main.afterFirstLayout(main.java:104)
at b4a.xChartsDemo.main.access$000(main.java:17)
at b4a.xChartsDemo.main$WaitForLayout.run(main.java:82)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5306)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
at dalvik.system.NativeStart.main(Native Method)

Itila Tumer said:

va.lang.NumberFormatException: Invalid double: "null"

Click to expand...

Check the code you are using. Check the values.
Seems that the value you are trying to convert to a double is not a number

DonManfred said:

Check the code you are using. Check the values.
Seems that the value you are trying to convert to a double is not a number

Click to expand...

I didn't make any changes. I wanted to run the demo project.

I just downloaded the xChart_V3_8.zip file from the forum and running the B4A project, you are right, I get the same error.
I am very sorry for the inconvenience.
As a workaround, load the program in the IDE, run the Designer, and quit it, and confirm to save it. Then the program works.
The project has been updated in the first post in the xChart class thread.

klaus said:

I just downloaded the xChart_V3_8.zip file from the forum and running the B4A project, you are right, I get the same error.
I am very sorry for the inconvenience.
As a workaround, load the program in the IDE, run the Designer, and quit it, and confirm to save it. Then the program works.
The project has been updated in the first post in the xChart class thread.

Click to expand...

Thanks, I have one more question.
The data in the dynamic graph is random.
I want to send data from a list or array.
I've been in a few trials, but it hasn't. How can I do it?

Use smothing like this:
AddLineMultiplePoints(X As String, YArray As Double, ShowTick As Boolean)
X = String for the X axis value
YArray = Array of Doubles with the Y values.
True = Show the x value on the chart.