B4J Question [B4X] Creating objects of a variable Class at runtime

Alessandro71 · Aug 15, 2025

with reference to this thread:

[Server] Building web servers with B4J

Edit: Web Apps tutorial: http://www.b4x.com/android/forum/threads/webapp-web-apps-overview.39811/ The server implementation is based on a popular and powerful Java server library named Jetty (license) The database connection pooling implementation is based on c3p0 (license). B4J Server...

www.b4x.com

i see there's and AddHandler sub that, as second parameter, has an object Class name.

B4X:

AddHandler("/hello", "HelloPage", False)

the Server object, later will create an object much like

B4X:

Dim runtimeobject as HelloPage

where the Class of runtimeobject will be the one specified as parameter of AddHandler.

i'm developing a cross-platform app (Android/iOS) that would benefit from using the same method: defining a variable number of objects at runtime from a Class not statically defined at compile time.

if there a way to get this working on B4A and B4i?

Erel · Aug 17, 2025

Not really. Much better to create a "factory" sub:

B4X:

Public Sub CreateObject (ClassName As String) As Object
 Select ClassName
   Case "Object1"
     Dim o1 As Object1
      o1.Initialize
      Return o1
  Case "Object2"
    Dim o2 As Object2
 ...

Alessandro71 · Aug 17, 2025

Erel said:
Not really. Much better to create a "factory" sub:

not really "elegant" but i understand the language lacks a suitable construct.
please consider it for next enhancements to the B4X language.

B4J Question [B4X] Creating objects of a variable Class at runtime

Alessandro71

Well-Known Member

[Server] Building web servers with B4J

Erel

B4X founder

Alessandro71

Well-Known Member

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B4J Question [B4X] Creating objects of a variable Class at runtime

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