Unable to addComponentListener to JFrame

[vsquared]

Does anyone know how to fix this demo? I'm trying to get the JTextArea component to resize with the JFrame and not unable to satisfy the parameter requirement for addComponentListener(something). It seems to want a class for the parameter but I can't come up with the correct syntax. Thanks for any insight.

# Uses Import mode for py5

from java.awt import *
from javax.swing import *
from java.awt.event import ComponentListener

_wndW = 400
_wndH = 200

# Unable to extend class with ComponentListener(ComponentListener)
class MyComponentListener:
  print("ComponentListener called")
  def componentResized(event):
    print("component resized")
  def componentMoved(event): pass
  def componentShown(event): pass
  def componentHidden(event): pass
  
listener = MyComponentListener()

def txtArea():
  global frame
  txtArea = JTextArea("")
  txtArea.setBounds(20,20,_wndW-40,_wndH-40)
  frame.add(txtArea)
  txtArea.repaint()
            
def setup():
  global frame
  size(_wndW, _wndH)
  wnd = get_surface()
  wnd.set_title('Resizable Window')
  canvas = wnd.get_native()
  frame = canvas.getFrame()
  frame.remove(canvas)
  frame.setResizable(True)
  txtArea()
  frame.addComponentListener(listener)

Error Message:

Output:

[GoToLoop]

You import ComponentListener, but then you overwrite it w/ class ComponentListener:!

You may try to inherit from it. Not sure if it works though:
class MyComponentListener(ComponentListener):

[vsquared]

Not sure if it works though
It doesn't.
TypeError: Java classes cannot be extended in Python
I'd like to use the original that I imported, but don't know how to do it. Thonny won't let me create an instance of it like this:
listener = ComponentListener()
TypeError: Cannot create Java interface instances

[hx2A]

JPype doesn't let you inherit from a Java class but you can implement a Java interface. I recommend reading the JPype documentation for more information about how to proceed here.

[GoToLoop]

Asked Bing AI and this is what I've got:

from java.awt.event import ComponentListener
from jpype import JProxy

class MyListener:
    def componentResized(self, e): print("Resized!")
    def componentMoved(self, e): pass
    def componentShown(self, e): pass
    def componentHidden(self, e): pass

listener = JProxy(ComponentListener, inst=MyListener())

[hx2A]

Try that but it looks inconsistent with how I understand JPype's JProxy to work. You need to add Python decorators to the implemented methods and ComponentListener must be a Java interface.

[vsquared]

@GoToLoop Thank you, thank you! JProxy is your friend.

This works:

# Uses Import mode for py5

from java.awt import *
from javax.swing import *
from java.awt.event import ComponentListener
from jpype import JProxy

_wndW = 400
_wndH = 200

class MyComponentListener():
  global txtArea,frame
  def componentResized(event):
    txtArea.setBounds(20,20,frame.getWidth()-40,frame.getHeight()-70)
  def componentMoved(event): pass
  def componentShown(event): pass
  def componentHidden(event): pass

listener = JProxy(ComponentListener, inst=MyComponentListener)    

def txtArea():
  global frame,txtArea
  txtArea = JTextArea("")
  txtArea.setBounds(20,20,_wndW-40,_wndH-40)
  frame.add(txtArea)
  txtArea.repaint()
            
def setup():
  global frame,txtArea
  size(_wndW, _wndH)
  wnd = get_surface()
  wnd.set_title('Resizable Window')
  canvas = wnd.get_native()
  frame = canvas.getFrame()
  frame.remove(canvas)
  frame.setResizable(True)
  txtArea()
  frame.addComponentListener(listener)

[GoToLoop]

The reason interface ComponentListener requires JProxy is b/c it's not a @FunctionalInterface:
https://docs.Oracle.com/en/java/javase/21/docs/api/java.base/java/lang/FunctionalInterface.html

That is, ComponentListener has 4 abstract methods rather than just 1:
https://docs.Oracle.com/en/java/javase/21/docs/api/java.desktop/java/awt/event/ComponentListener.html

And therefore, it's not qualified to be passed to addComponentListener() as a simple lambda.

[vsquared]

That is, ComponentListener has 4 abstract methods rather than just 1:
And therefore, it's not qualified to be passed to addComponentListener() as a simple lambda.

Among the many things I tried was adding the other three methods and it still failed:
TypeError: No matching overloads found for java.awt.Component.addComponentListener (MyComponentListener), options are: public synchronized void java.awt.Component.addComponentListener (java.awt.event.ComponentListener)
Proxy is the only thing that works in Python. Original post edited so that you can see that it still fails with all four methods added.