B4J Question [Solved]How to code William's PyBridge example

Theera · Feb 17, 2025

Refer to this ,I 've coded as following William's example which is attached file. I have still error codea after clicked the button.
My the lastest I have edited,but I have still error code.

B4X:

Dim opt As PyOptions = Py.CreateOptions(File.Combine(File.DirApp, "C:\Python/python310/python.exe"))

Erel · Feb 17, 2025

Use this code:

B4X:

Private Sub Fibonacci(n As Int) As PyWrapper
    Dim Code As String = $"
#python code here

#Fibonacci numbers module
def Fibonacci(n):
    result=[]
    a,b=0,1
    while a<n:
        result.append(a)
        a,b=b,a+b    
    return result
"$
    Return Py.RunCode("Fibonacci", Array(n), Code)
End Sub

I've reset the indentation and set it again.

teddybear · Feb 17, 2025

You should create a PyBridge with Python project instead of b4xpages

Erel · Feb 17, 2025

You should post the error message. We cannot guess it.

Theera · Feb 17, 2025

Server is listening on port: 61177
Python executable not found!
Call B4XPages.GetManager.LogEvents = True to enable logging B4XPages events.
Failed to start Python process.
org.apache.commons.exec.ExecuteException: Execution failed (Exit value: -559038737. Caused by java.io.IOException: Cannot run program "C:\_2_B4J~1\PYFIBO~1\B4J\Objects\Python\python310\python.exe" (in directory "."): CreateProcess error=2, The system cannot find the file specified)
Process completed. ExitCode: -559038737
b4xset._contains (java line: 61)
java.lang.NullPointerException: Cannot invoke "b4j.example.b4xorderedmap._containskey(Object)" because "this._map" is null
at b4j.example.b4xset._contains(b4xset.java:61)
at b4j.example.pybridge._registermember(pybridge.java:515)
at b4j.example.pybridge._runcode(pybridge.java:527)
at b4j.example.b4xmainpage._fibonacci(b4xmainpage.java:183)
at b4j.example.b4xmainpage$ResumableSub_Button1_Click.resume(b4xmainpage.java:143)
at b4j.example.b4xmainpage._button1_click(b4xmainpage.java:119)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:111)
at anywheresoftware.b4a.BA$1.run(BA.java:236)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:457)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:456)
at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:184)
at java.base/java.lang.Thread.run(Thread.java:1589)

Theera · Feb 17, 2025

I

teddybear said:
You should create a PyBridge with Python project instead of b4xpages

View attachment 161796

Yeah. I have done.

Theera · Feb 17, 2025

It should be configured path to python,or not?

teddybear · Feb 17, 2025

Theera said:
It should be configured path to pyhon,or not?

Create py project. you need not to do anything.

Theera · Feb 17, 2025

B

teddybear said:
Create py project. you need not to do anything.

But my path to refer Python is wrong.

Daestrum · Feb 17, 2025

Dim opt As PyOptions = Py.CreateOptions(File.Combine(File.DirApp, "C:\Python/python310/python.exe"))

This makes no sense

Try
Dim opt As PyOptions = Py.CreateOptions(File.Combine("", "C:\Python/python310/python.exe"))

Theera · Feb 17, 2025

Daestrum said:
Dim opt As PyOptions = Py.CreateOptions(File.Combine(File.DirApp, "C:\Python/python310/python.exe"))

This makes no sense

Try
Dim opt As PyOptions = Py.CreateOptions(File.Combine("", "C:\Python/python310/python.exe"))

It still is error.

Theera · Feb 17, 2025

Server is listening on port: 61427
Call B4XPages.GetManager.LogEvents = True to enable logging B4XPages events.
connected
starting PyBridge v0.50
watchdog set to 30 seconds
Connecting to port: 61427
Error occurred on line: 61 (B4XMainPage)
(b4xmainpage._fibonacci) - Python Error (TabError) - Method: module.exec: inconsistent use of tabs and spaces in indentation (<string>, line 7)
pywrapper.raiseError (java line: 607)
java.lang.RuntimeException: (b4xmainpage._fibonacci) - Python Error (TabError) - Method: module.exec: inconsistent use of tabs and spaces in indentation (<string>, line 7)
at b4j.example.pywrapper.raiseError(pywrapper.java:607)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at anywheresoftware.b4j.object.JavaObject.RunMethod(JavaObject.java:132)
at b4j.example.pywrapper._getvalue(pywrapper.java:239)
at b4j.example.b4xmainpage$ResumableSub_Button1_Click.resume(b4xmainpage.java:152)
at anywheresoftware.b4a.BA.checkAndRunWaitForEvent(BA.java:156)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:105)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:98)
at anywheresoftware.b4a.keywords.Common$3.run(Common.java:1172)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:457)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:456)
at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:184)
at java.base/java.lang.Thread.run(Thread.java:1589)

teddybear · Feb 17, 2025

Create a PY project, just run it, it should work, and then modify it for William's example

Daestrum · Feb 17, 2025

(b4xmainpage._fibonacci) - Python Error (TabError) - Method: module.exec: inconsistent use of tabs and spaces in indentation (<string>, line 7)

That is because you cannot mix tabs and spaces in python source code. Use one or the other.

Erel · Feb 17, 2025

Use this code:

B4X:

Private Sub Fibonacci(n As Int) As PyWrapper
    Dim Code As String = $"
#python code here

#Fibonacci numbers module
def Fibonacci(n):
    result=[]
    a,b=0,1
    while a<n:
        result.append(a)
        a,b=b,a+b    
    return result
"$
    Return Py.RunCode("Fibonacci", Array(n), Code)
End Sub

I've reset the indentation and set it again.

Theera · Feb 17, 2025

What happened about Python code?

Erel · Feb 17, 2025

What exactly are you asking?

[PyBridge] The very basics

PyBridge is a framework that allows accessing Python libraries from within B4J. It works by starting a Python process that connects to the B4J process. The Python process receives commands from the B4J process and executes them. From the developer perspective it is very similar to accessing...

www.b4x.com

Theera · Feb 17, 2025

Erel said:
What exactly are you asking?

After I remarked my Python code, and use your python code, It is Ok.
P.s. It is about configured path to Python directory, too.

Theera · Feb 17, 2025

My problem is about your done" I've reset the indentation and set it again."

Daestrum · Feb 17, 2025

The IDE will use tabs if you add a line of code. Python code expects either tabs or spaces but not both. You can ensure it only uses spaces by doing this sort of thing.

B4X:

    Dim Code As String = $"
#python code here

#Fibonacci numbers module
def Fibonacci(n):
    result=[]
    a,b=0,1
    while a<n:
        result.append(a)
        a,b=b,a+b    
    return result
"$.Replace(TAB,"    ") ' replace tabs with 4 spaces.

Theera · Feb 17, 2025

Ok, I know all of my problems
1. It is about configured path to Python directory
(My Python is C:\Python\python310\python.exe, but others may be different from mine)

B4X:

Dim opt As PyOptions = Py.CreateOptions(File.Combine("", "C:\Python\python310\python.exe"))

2. It is about the indentation each line which is different from other languages programming.

B4J Question [Solved]How to code William's PyBridge example

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