B4J Tutorial [ABMaterial/BANano] Making BANano Libraries for ABMaterial

PREFACE:
As some may know, ABM has some basic JavaScript functionality build-in called B4JS. It was the predecessor of BANano. However, because of the design of ABM, B4JS could never reach its full potential. But from that came the idea to write a full blown true B4J to JavaScript Transpiler was born: BANano! (Thinking in retrospect, B4JS in ABM may have been a poor choice of words, as BANano covers much more that term ;) )

In my day job, we still use ABM in most of our client projects. But sometimes we just miss that extra BANano can do on the Browser side. For new projects, we now mostly use a BANanoServer instead of an ABMServer, but we still have many ABM apps running and continue to write extra functionalities to those apps. What if we could use BANano generated code IN ABMaterial?

Hence this new idea came up: If BANano could generate .b4xlib libraries, writing the 'glue' between ABM and BANano, that would be a great asset to add features to ABM!

An Example of an ABMButton hover extension:

1. One writes BANano code that when one hovers over an ABMButton, it changes color

In pure ABM, it is kind of a hassle, but in BANano this is pretty simple:

The ABMHover Class
B4X:
#Event: Hover(ID As String, IsOver As Boolean)

Sub Class_Globals
    Private BANano As BANano 'ignore
    Private mEventName As String
End Sub

'Initializes the object, setting the event
Public Sub Initialize(eventName As String)
    mEventName = eventName
End Sub

' Adds hover functionality to an ABM Component
public Sub AddHover(ID As String)
    ' get the element with the ID
    Dim mElement As BANanoElement
    mElement.Initialize("#" & ID)

    ' add the Mouse Enter and Leave events to the element
    Dim event As Object
    mElement.AddEventListener("mouseenter", BANano.CallBackExtra(Me, "HandleMouseEnter", event, Array(mElement)),True)
    mElement.AddEventListener("mouseleave", BANano.CallBackExtra(Me, "HandleMouseLeave", event, Array(mElement)),True)
End Sub

' the Callback for the Mouse Enter event
private Sub HandleMouseEnter(event As BANanoEvent, Element As BANanoElement) 'ignore
    ' make the button red
    Element.RemoveClass("light-blue").AddClass("red")
    ' optionaly raise an event back to ABM
    BANano.RaiseEventToABM(mEventName & "_Hover", Array("ID","IsOver"), Array(Element.Name, True), "")
End Sub

' the Callback for the Mouse Leave event
private Sub HandleMouseLeave(event As BANanoEvent, Element As BANanoElement) 'ignore
    ' make the button blue again
    Element.RemoveClass("red").AddClass("light-blue")
    ' optionaly raise an event back to ABM
    BANano.RaiseEventToABM(mEventName & "_Hover", Array("ID","IsOver"), Array(Element.Name, False), "")
End Sub

NOTES:
a. You can use BANano.RaiseEventToABM() to make a call back to the ABM server. This could be just an notice that it is done, or even a result.
But it is also possible to get something returned by the BANano methods immediately:
B4X:
public Sub TestReturningSomething(someParam As String) As Boolean
    Return True
End Sub

You can define your Event for ABM with:
B4X:
#Event: Hover(ID As String, IsOver As Boolean)

b: Comments you add before the Method declaration will be visible in the final ABMBANano lib.

2. Making a ABM BANano b4xlib

In our main, you make one call (similar to the BANano.BuildAsB4XLib() for normal BANano Libraries):
B4X:
Sub Process_Globals
    Private BANano As BANano 'ignore
End Sub

Sub AppStart (Form1 As Form, Args() As String)
    ' you can change some output params here
    BANano.Initialize("BANano", "Hover",7) '<--------------------- the name of our lib
    BANano.JAVASCRIPT_NAME = "hover.js" '<------------------- the name of the generated JavaScript file

    ' start the build
    #if release
        BANano.BuildAsB4XlibForABM("K:\_ONETWO210203\Work2020\Objects\www", "1.0") '<-----------------------
        ExitApplication
    #else
        BANano.Build(File.DirApp)
    #end if
End Sub

' HERE STARTS YOUR APP
Sub BANano_Ready()

End Sub

The Result is this:
B4X:
Reading B4J INI in C:\Users\pi\AppData\Roaming\Anywhere Software\B4J to find Additional Libraries folder...
Found Additional Libraries folder: K:\B4J\AddLibraries
Starting to transpile...
Building K:\BANano6.11\ABMJavaScript\Objects\Hover\scripts\hover.js
Copying CSS files to WebApp assets...
Copying Javascript files to WebApp assets...
Starting to build the ABMBANanoHover.b4xlib...
==========================================================================
The following files have been created in your Additional Libraries folder K:\B4J\AddLibraries
-> ABMBANanoHover.b4xlib
-> ABMBANanoHover.Assets.zip
-> ABMBANanoHover.txt
--------------------------------------------------------------------------
Read the instructions in ABMBANanoHover.txt on how to deploy and use this library!
==========================================================================

As you can see, three files are generated:
- The .b4xlib itself
- a .zip file containing the assets (this is the CSS/JS BANano generated) MUST BE NEXT TO THE .b4xlib!
- a .txt file with some usage info:

Here for example the .txt content looks like this:
B4X:
========== Using the ABMBANanoHover Library in ABM: CHECKLIST ===============

---------- 1. Add the ABMBANanoHover library to your project ---------------

---------- 2. Add these lines in BuildPage() ---------------
page.AddExtraJavaScriptFile("bananocore.js")
page.AddExtraJavaScriptFile("Hover/hover.js")
' unless you use a specific other place where your Static Files are, this will always be "www"
Hover.UnzipAssets("www")

---------- You can now use your BANano Classes in ABM like a normal B4J class
EXAMPLE:
Dim myFirstBANanoClass As FirstBANanoClass
myFirstBANanoClass.Initialize(ws, "myFirstBANanoClass")
myFirstBANanoClass.MyFirstMethod(ws, "Hello World!")

It is a short checklist of what you have to do to use this library in ABM.

3. So we follow these few simple instructions:

3.1. In our ABM project, First we pick the newly generated library:

1611312130658.png


3.2 In BuildPage(), we add the assets:

1611312458464.png


And now we can just start using our BANano Hover code in ABM! 😊

B4X:
public Sub ConnectPage()
   Dim button as ABMButton
   button.Initialize(page, "button", "", "", "Say Hello", "")
   page.Cell(2,1).AddComponent(button)

   ' refresh the page
   page.Refresh
   ' Tell the browser we finished loading
   page.FinishLoading
   ' restore the navigation bar position
   page.RestoreNavigationBarPosition

   Dim MyJS as ABMHover
   myJS.Initialize(ws, "myJS") ' <<<<<<<<<<<<<<<<<<<< New in 6.59 the first parameter ws has to be passed
   myJS.AddHover(ws, "button")  ' <<<<<<<<<<<<<<<<<<<< New in 6.59 the first parameter ws has to be passed
End Sub

' our Hover event (the BANano.RaiseEventToABM we did)
Sub myJS_Hover(ID As String, IsOver as Boolean)
   Log("Hover on " & ID & " -> Is Over: " & IsOver)
End Sub

And this is the result (Notice the color of the button changing and in the B4J log also the Events back):



HOW IT WORKS (For those interested in the mechanics behind it)

The .b4xlib created is a 'glue' lib with all the Public methods in it, making calls to their BANano counterparts:

For example this snippet from the ABMBANanoHover.b4xlib):
B4X:
public Sub AddHover(ws as WebSocket, ID As String)
    ws.Eval("BANhover['" & UniqueBANID & "'].addhover(arguments[0])", Array (id))
    ws.Flush
End Sub

When calling AddHover in ABM, we forward it to the method in the BANano library.

Alwaysbusy
 

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Last edited:

alwaysbusy

Expert
Licensed User
VERY IMPORTANT!

Do NOT use version 6.57, but the new version 6.59!

1. [FIX] ABMBANano Libraries losing Websocket connection
--------------------------------------------------------
I had to find this out myself the hard way, but there was a major flaw in the generation of the 'glue' code:
It only worked for ONE instance of the page. So as soon as two or more users accessed the page, the previous ones broke the connection.

You will have to recompile your existing ABMBANanoLibraries with this new version and make the changes in the calling ABM app described below:

Consequences on this fix:

a. Step 3. (Call this method in ConnectPage() to set the WebSocket) has to be removed
b. In each call to an ABMBANano library in ABM, you must pass the WebSocket (ws) in the method as the first parameter.

Alwaysbusy
 

Cableguy

Expert
Licensed User
#24 post only mentions the websocket bug fix, and in the ordinal post I only found the very few code changes regarding this new version. (Found it!!)
Anyway, Thank You
 
Last edited:

Cableguy

Expert
Licensed User
Hi Alain,

I was about to recompile the Hover BananoLib and noticed that you forgot to update the Hover Class example code to reflect the changes in 6.59.

The Initialize(ws, "myJS") and AddHover(ws, "button") declarations are still in the old schema. Also, the "ws" part of the code in that class is missing.
I'm guessing this is an important part to develop these libraries.
 

Cableguy

Expert
Licensed User
You don have to make any changes in the mehod definitions of you BANano class. The 'ws as WebSocket' is automatically injected in the 'glue' code when you run BANano.BuildAsB4XlibForABM().
Ok, but in ABMaterial, when I start typing the methods, it still has the old defenition.... Do I need to first delete the previously created lib?
 

Cableguy

Expert
Licensed User
Well, refreshing may help...
Just browsed the extralibs folder and found that the lib files were NOT overwritten with the new ones...
So I just deleted them and recompiled.... The logs state, as it should, that the extra libs folder is found, but nothing gets added there.
 
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