Android Tutorial [B4X] Corona Cases - Cross platform Example



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
 
Last edited:
Click to expand...

MarcoRome

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Hi Erel.
Return this error:


The library are:

 

Xfood

Expert
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it would be nice to add a status as default, and some labels that give you the indication of the cell date
total deaths, total infected, total recovered, new cases, new deaths
if anyone can make these changes it would be welcome,
congratulations from Erel for everything.
"EVERYTHING WILL BE FINE"
 

josejad

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I get this error in B4J



Waiting for debugger to connect...
Program started.
Read countries data
Ha ocurrido un error en la línea: 297 (xChart)
java.lang.NullPointerException
at anywheresoftware.b4a.objects.B4XViewWrapper$XUI.PaintOrColorToColor(B4XViewWrapper.java:886)
at b4j.example.xchart._designercreateview(xchart.java:2595)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:632)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:237)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:167)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:91)
at anywheresoftware.b4a.shell.ShellBA.raiseEvent2(ShellBA.java:98)
at anywheresoftware.b4j.objects.CustomViewWrapper.AfterDesignerScript(CustomViewWrapper.java:62)
at anywheresoftware.b4j.objects.LayoutBuilder.loadLayout(LayoutBuilder.java:93)
at anywheresoftware.b4j.objects.PaneWrapper.LoadLayout(PaneWrapper.java:84)
at anywheresoftware.b4a.objects.B4XViewWrapper.LoadLayout(B4XViewWrapper.java:486)
at b4j.example.sharedmain$ResumableSub_LoadData.resume(sharedmain.java:530)
at anywheresoftware.b4a.shell.DebugResumableSub$DelegatableResumableSub.resumeAsUserSub(DebugResumableSub.java:47)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:632)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:237)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:167)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:91)
at anywheresoftware.b4a.shell.ShellBA.raiseEvent2(ShellBA.java:98)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:78)
at anywheresoftware.b4a.shell.DebugResumableSub$DelegatableResumableSub.resume(DebugResumableSub.java:42)
at anywheresoftware.b4a.BA.checkAndRunWaitForEvent(BA.java:136)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:85)
at anywheresoftware.b4a.shell.ShellBA.raiseEvent2(ShellBA.java:98)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:78)
at anywheresoftware.b4a.keywords.Common$3.run(Common.java:1086)
at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
at java.lang.Thread.run(Thread.java:748)
 

Erel

B4X founder
Staff member
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Longtime User
I've uploaded a new version. It depends on xChart 4.70+ which makes it simpler to change the chart size after it is created. This means that we no longer need to wait for the table to resize itself. Instead we are doing it later in DataUpdated event.

It is done with this code:
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
            '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)
 
Last edited:
M

Mahares

Expert
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Longtime User
In order to make the Yaxis scale less crowded, I added this line to the code to reduce the number of Y intervals:
B4X: 
Chart.NbYIntervals=6   'I suppose it could also be done via designer
But what I really wanted to do was to be able to have the ability to hide Yvaluess from displaying on the Y Axis. For instance if my Y internal is 10, I wanted to hide every other Yvalue from displaying on the Y axis. I could not find a property for that in xChart., unless I miss it.
 

klaus

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Mahares said:
'I suppose it could also be done via designer
Click to expand...
Sure, you can!
For instance if my Y internal is 10, I wanted to hide every other Yvalue from displaying on the Y axis. I could not find a property for that in xChart., unless I miss it.
Click to expand...
Not yet.
 
M

Mahares

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klaus said:
Not yet.
Click to expand...
One very valuable feature, if it can be implemented would be to have a second Yaxis on the right for the 2nd set of data, especially in a case similar to this app, the death value is much smaller than the cases value, which in many graphs the plot for the deaths is almost flat.
 

josejad

Expert
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Longtime User
Waldemar Lima said:
show this errors
Click to expand...
Post your error like text, not image.
download the missing library and copy it to your external libraries folder

[B4X] [XUI] xChart Class and b4xlib

Current version 9.8 A lite version is available: xChartLite. A mini version is also available: xChartMini. Learning B4XViews and XUI, I wrote this CustomView xChart Class. It is an evolution of Erels' Android Charts Framework. The xChart custom view is a B4X libary. It works on all three...
www.b4x.com

How do you install the libraries

Hi Everyone, If this post in in the wrong place, please move it to the correct location. I noticed many nice libraries but I need instructions on installing them. The one I'm interested in trying is the phone state listener. How do I install it? Thanks. Truly, Emad
www.b4x.com
 

klaus

Expert
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I suppose that you have copied the xChart.xml file to the AdditionalLibraries folder.
You must remove it, only copy the xChart.b4xlib file.
You should setup the AdditionalLibraries folder like described HERE.
 

klaus

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Mahares said:
But what I really wanted to do was to be able to have the ability to hide Yvaluess from displaying on the Y Axis . . .
Click to expand...
Mahares said:
One very valuable feature, if it can be implemented would be to have a second Yaxis on the right for the 2nd set of data . . .
Click to expand...
Hi Mahares,
Is this what you were expecting?



The work is still in progress, needs some fine tuning.
 
M

Mahares

Expert
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klaus said:
The work is still in progress, needs some fine tuning.
Click to expand...
That looks great klaus, It does not look like you have too far to go if you ask me. Hopefully, all the properties available now for the left Yaxis will also be available for the right Yaxis such as text color, size,, spacing intervals, etc. Are you sure you are 75 years old and not pulling our legs?
 
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