Android Tutorial [B4X] Corona Cases - Cross platform Example

Erel · Mar 18, 2020

Data source: https://ourworldindata.org/coronavirus-source-data

Cross platform example based on B4XTable and xChart 4.70+.
Follows the same structure as explained here: https://www.b4x.com/android/forum/threads/b4x-cross-platform-example.114125/#content
Practically all of the code is shared between the three platforms. The layouts were copied and pasted.

The project includes a default dataset in the assets folder. It tries to download an updated dataset when the app starts.

Depends on: xChart and other internal libraries.

Executable jar (Java 8 needs to be installed): https://www.b4x.com/b4j/files/CoronaCases.jar

Similar example based on xCustomListView instead of B4XTable: https://www.b4x.com/android/forum/t...loading-extension-for-xcustomlistview.115289/

Download link: www.b4x.com/android/files/CoronaCases.zip

klaus · Mar 23, 2020

Mahares said:
Hopefully, all the properties available now for the left Yaxis will also be available for the right Yaxis such as text color . . .

I answered in the xChart thread, because this discussion is not really related to this thread.

Mahares said:
Are you sure you are 75 years old and not pulling our legs?

The body yes, and fortunately I am in good health and in a good shape.
In the mind and brain I feel younger, hopefully it's not only illusion.

skyracer90 · Mar 24, 2020

B4A 9.8
Hi Erel,
i have Download your Example ans the XChart Lib, but i dont Understand this Error....
Logger verbunden mit: 9DCDUxxxxxxxxxxxxxxx
--------- beginning of system
--------- beginning of main
Copying updated assets files (3)
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
Read countries data
Error occurred on line: 505 (B4XTable)
java.lang.RuntimeException: Object should first be initialized (B4XView).
at anywheresoftware.b4a.AbsObjectWrapper.getObject(AbsObjectWrapper.java:50)
at anywheresoftware.b4a.objects.B4XViewWrapper.asViewWrapper(B4XViewWrapper.java:70)
at anywheresoftware.b4a.objects.B4XViewWrapper.getTag(B4XViewWrapper.java:557)
at b4a.example.b4xtable._setpagelabelstate(b4xtable.java:2010)
at b4a.example.b4xtable._clearnavigationstate(b4xtable.java:1936)
at b4a.example.b4xtable$ResumableSub_Clear.resume(b4xtable.java:532)
at b4a.example.b4xtable._clear(b4xtable.java:395)
at b4a.example.sharedmain._preparetable(sharedmain.java:555)
at b4a.example.sharedmain._loaddata(sharedmain.java:412)
at b4a.example.sharedmain._initialize(sharedmain.java:88)
at b4a.example.main._activity_create(main.java:391)
at java.lang.reflect.Method.invoke(Native Method)
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.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
at b4a.example.main.afterFirstLayout(main.java:104)
at b4a.example.main.access$000(main.java:17)
at b4a.example.main$WaitForLayout.run(main.java:82)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:101)
at android.os.Looper.loop(Looper.java:166)
at android.app.ActivityThread.main(ActivityThread.java:7523)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)
** Activity (main) Resume **

Erel · Mar 25, 2020

You are probably using an old version of B4XTable. Use v1.21+.

skyracer90 · Mar 26, 2020

Erel said:
You are probably using an old version of B4XTable. Use v1.21+.

Thx,Erel. It Works!

semar · Mar 27, 2020

Hi,
I get this by compiling:

B4X:

B4A Version: 9.80
Java Version: 11
Parsing code.    (0.20s)
Building folders structure.    (0.03s)
Running custom action.    Error
-------------------------------------------------------------------------------
   ROBOCOPY     ::     Robustes Dateikopieren fr Windows                             
-------------------------------------------------------------------------------
  Gestartet: Freitag, 27. M„rz 2020 12:28:58
   Quelle : C:\sergio\B4A\examples\co\Shared Files\
     Ziel : C:\sergio\B4A\examples\co\B4A\Files\
    Dateien : *.*
        
  Optionen: *.* /DCOPY:DA /COPY:DAT /R:1000000 /W:30
------------------------------------------------------------------------------
2020/03/27 12:28:58 FEHLER 2 (0x00000002) Zugriff auf Quellverzeichnis C:\sergio\B4A\examples\co\Shared Files\
Das System kann die angegebene Datei nicht finden.

Jorge M A · Mar 27, 2020

Comment or delete to the line for ROBOCOPY command and copy the file "full_data.csv" into the files folder of your project.

semar · Mar 27, 2020

Thank you Jorge, I' ll try that !

semar · Mar 27, 2020

Solved, the library B4XTable was old.

Mahares · Mar 31, 2020

In the Corona example by Erel on the first post, I tried the new feature from xChart 4.90: chart.DifferentScales=True (added by klaus) to use the 'Deaths' in the 2nd Yaxis (right) since the values are a lot smaller than the cases, but everywhere I put it in the code it hangs up the program. Where exactly does that line of code go?
Thank you

Jorge M A · Apr 1, 2020

B4X:

Sub B4XTable1_DataUpdated
    For i = 0 To B4XTable1.VisibleRowIds.Size - 1
        Dim RowId As Long = B4XTable1.VisibleRowIds.Get(i)
        Dim pnl As B4XView = GraphColumn.CellsLayouts.Get(i + 1) '+1 because of header layout
        Dim ChartParent As B4XView = pnl.GetView(1)
        If RowId > 0 Then
            ChartParent.SetLayoutAnimated(0, 0, 0, pnl.Width, pnl.Height)
            ChartParent.Visible = True
            Dim Chart As xChart = ChartParent.Tag
            
            Chart.DifferentScales=True '<-------
            
            'this is only needed in B4A as the Base_Resize event will be raised automatically in B4J and B4i.
            If xui.IsB4A Then Chart.Base_Resize(ChartParent.Width, ChartParent.Height)

            Chart.ClearData
            Chart.AddLine("Cases", xui.Color_Blue)
            Chart.AddLine("Deaths", xui.Color_Red)
            Dim Country As String = B4XTable1.GetRow(RowId).Get(CountryColumn.Id)
            AddPointsToChart(CountriesData.Get(Country), Chart)
            Chart.DrawChart
        Else
            ChartParent.Visible = False
        End If
    Next
End Sub

Mahares · Apr 1, 2020

Jorge M A said:
Chart.DifferentScales=True '<-------

Did it work for you where you placed it. Because I have already tried it there on a 10 inch tablet, the app locked up. I tried it on a Galaxy S6 phone, it showed the first page and locked up. Then I tried it on a Galaxy S10e phone, it showed the first page and then it locked up. Please check it out again.

Jorge M A · Apr 1, 2020

Mahares said:
Did it work for you where you placed it.

Yes, Buuuut... I’m in B4J.
Tomorrow I’ll check it in B4A, and report back.

klaus · Apr 1, 2020

I set it in the Designer, but as Mahares reported, the first page is shown and then the program is blocked.
I saw it yesterday evening and it's on my to do list for this morning to look at it.

klaus · Apr 1, 2020

The xChart library has been updated to version 5.0.
There was a problem when the min and max values of a line were the same.
You should set these two properties in the Designer, no need to do it in the code:

Erel · Jul 15, 2020

I've updated the example with a new dataset.

Jorge M A · Jul 15, 2020

Erel said:
I've updated the example with a new dataset.

Happy about the new example , but sad that the information is still relevant.?

Android Tutorial [B4X] Corona Cases - Cross platform Example

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