listbox.py

# http://www.daniweb.com/software-development/python/code/216827/working-with-a-tkinter-listbox-python#

import Tkinter as tk # gives tk namespace
import os

def directory_list():
    dirlist = os.listdir("/usr")
    from pprint import pprint
    pprint(dirlist)

def add_item():
    listbox1.insert(tk.END, enter1.get())

def delete_item():
    try:
        index = listbox1.curselection()[0]
        listbox1.delete(index)
    except IndexError:
        pass

def get_list(event):
    # reads the listbox selection and puts result in entry widget
    # get selected line index
    index = listbox1.curselection()[0]
    # get the line's text
    seltext = listbox1.get(index)
    # delete previous text in enter1
    enter1.delete(0, 50)
    # now display the selected text
    enter1.insert(0, seltext)

def set_list(event):
    # inserts an edited line 
    try:
        index = listbox1.curselection()[0]
        # delete old listbox line
        listbox1.delete(index)
    except IndexError:
        index = tk.END
    # insert edited item back into listbox1 at index
    listbox1.insert(index, enter1.get())

def sort_list():
    temp_list = list(listbox1.get(0, tk.END))
    temp_list.sort(key=str.lower)
    # delete contents of present listbox
    listbox1.delete(0, tk.END)
    # load listbox with sorted data
    for item in temp_list:
        listbox1.insert(tk.END, item)

def save_list():
    # get a list of listbox lines
    temp_list = list(listbox1.get(0, tk.END))
    # add a trailing newline char to each line
    temp_list = [chem + '\n' for chem in temp_list]
    # give the file a different name
    fout = open("chem_data2.txt", "w")
    fout.writelines(temp_list)
    fout.close()
    
# create the sample data file
str1 = """ethyl alcohol
ethanol
ethyl hydroxide
hydroxyethane
methyl hydroxymethane
ethoxy hydride
gin
bourbon
rum
schnaps
"""

fout = open("chem_data.txt", "w")
fout.write(str1)
fout.close()

# read the data file into a list
fin = open("chem_data.txt", "r")
chem_list = fin.readlines()
fin.close()

# strip the trailing newline char
chem_list = [chem.rstrip() for chem in chem_list]
root = tk.Tk()
root.title("Listbox Operations")

# create the listbox (note that size is in characters)
listbox1 = tk.Listbox(root, width=50, height=6)
listbox1.grid(row=0, column=0)

# create a vertical scrollbar to the right of the listbox
yscroll = tk.Scrollbar(command=listbox1.yview, orient=tk.VERTICAL)
yscroll.grid(row=0, column=1, sticky=tk.N+tk.S)
listbox1.configure(yscrollcommand=yscroll.set)

# use entry widget to display/edit selection
enter1 = tk.Entry(root, width=50, bg='yellow')
enter1.insert(0, 'Click on an item in the listbox')
enter1.grid(row=1, column=0)

# pressing the return key will update edited line
enter1.bind('<Return>', set_list)

# or double click left mouse button to update line
enter1.bind('<Double-1>', set_list)

# button to sort listbox
button1 = tk.Button(root, text='Sort the listbox ', command=sort_list)
button1.grid(row=2, column=0, sticky=tk.W)

# button to save the listbox's data lines to a file
button2 = tk.Button(root, text='Save lines to file', command=save_list)
button2.grid(row=3, column=0, sticky=tk.W)

# button to add a line to the listbox
button3 = tk.Button(root, text='Add entry text to listbox', command=add_item)
button3.grid(row=2, column=0, sticky=tk.E)

# button to delete a line from listbox
button4 = tk.Button(root, text='Delete selected line ', command=delete_item)
button4.grid(row=3, column=0, sticky=tk.E)

# load the listbox with data
for item in chem_list:
    listbox1.insert(tk.END, item)
    # left mouse click on a list item to display selection

listbox1.bind('<ButtonRelease-1>', get_list)
root.mainloop()