app.py

import gradio as gr

def dummy(fex):
  print(fex)
  return fex

with gr.Blocks() as demo:
  with gr.Row():
    fex1 = gr.FileExplorer(value="/content/test/untitled.txt", height=200)
    fex2 = gr.FileExplorer()
  btn=gr.Button()
  btn.click(dummy, fex1, fex2)

demo.launch(debug=True)