from __future__ import print_function

#
# Create a GUI with a text entry field.
#
try:
    import Tkinter
except ImportError:
    import tkinter as Tkinter

# We use the same pattern as tkinter_label_entry.py
def main():
    app = Tkinter.Frame()
    app.grid()
    make_ui(app)
    app.mainloop()

# "make_ui" is similar to the one in tkinter_label_entry2.py.
# In addition to echoing when a button is pressed, we also
# do it when the user hits the <return> key.
# 
# To get our function "echo_event" called, we need to link
# it to the "<Return>" (return key pressed) action using
# the "bind" method of the entry widget.  This call only
# binds the <Return> action for the one widget; if the user
# presses <return> in any other widget, "echo_event" will
# not be called.  Note that echo_cb and echo_event also
# have differing number of arguments.  "echo_cb" is a
# callback, so it has no arguments (other than the ones
# we define for our data).  "echo_event" is an "event
# handler", so its one argument is an event instance
# (again, other than the ones we define).
def make_ui(app):
    def quit_cb(app=app):
        app.quit()
    f1 = Tkinter.Frame(app)
    f1.grid(row=0, column=0, sticky="nsew")
    label = Tkinter.Label(f1, text="Prompt")
    label.grid(row=0, column=0)
    entry = Tkinter.Entry(f1)
    entry.grid(row=0, column=1)
    def echo_cb(entry=entry, label=label):
        label.config(text=entry.get())
    def echo_event(event, entry=entry, label=label):
        echo_cb(entry, label)
    entry.bind("<Return>", echo_event)

    f2 = Tkinter.Frame(app)
    f2.grid(row=1, column=0, sticky="nsew")
    button = Tkinter.Button(f2, text="Echo", command=echo_cb)
    button.grid(row=0, column=0)
    button = Tkinter.Button(f2, text="Quit", command=quit_cb)
    button.grid(row=0, column=1)

if __name__ == "__main__":
    main()
    print("Finished")