Display which widget has focus - python

Before you read:
I am a complete novice at programming let alone Python. I don't expect solutions. I will appreciate it even if I just get a pointer in the right direction. If you feel the way I've requested help is unrefined, please let me know so next time I need help, I'll do a better job at asking.
Goal:
I'm making a program to test how to get a program to respond depending on which widget has to focus on. Currently, I'm just having it respond by displaying 'what' has focus.
Eventually, once I've figured this out I can implement what I've learnt into another program I'm working on was focusing on an entry field will result in the field clearing of all input. So naturally, I will want this program to not only change the label but the entry widget too. That will be for later.
Progress:
I've managed to have the program print which widget has a focus in both the terminal and in a label widget.
Problem:
My issue is that the message is ugly, and I want it to look neater.
Example of the problem:
Instead of saying "Entry has focus", it says ".!frame.!entry {has focus}"
I have tried:
Checking if other's have made similar programs. The only one I found was how I made this much progress but it didn't make the text nicer. I've also done research on various sites on how Python handles certain commands I've used in this program.
I am a novice with programming so I admit I'm not completely sure what the best way to run this program is and so trying to research it is difficult for me.
Code:
# Call tkinter tools
from tkinter import *
from tkinter import ttk
"""
TODO:
Add different widgets that can 'gain' focus.
Print in the terminal which widget has focus.
Change entry and label text depending on which widget has focus.
"""
# Develop the window and frame
root = Tk()
root.title("Focus Test")
root.columnconfigure(0, weight = 1)
root.rowconfigure(0, weight = 1)
frame = ttk.Frame(root, padding = "1 1 1 1")
frame.grid(column = 0, row = 0, sticky = (N, S, E, W))
# Resizes columns in frame
for col in range(1, 3):
frame.columnconfigure(col, weight = 1)
# Resizes rows in frame
for row in range(1, 3):
frame.rowconfigure(row, weight = 1)
# Add response label
foc_labvar = StringVar()
foc_labvar.set("No focus")
foc_lab = ttk.Label(frame, width = 7, textvariable = foc_labvar)
foc_lab.grid(column = 2, row = 2, sticky = (W, E))
# Add entry box
foc_entvar = StringVar()
foc_entvar.set("Entry widget")
foc_ent = ttk.Entry(frame, width = 7, textvariable = foc_entvar)
foc_ent.grid(column = 1, row = 1, sticky = (W, E))
# Add button
foc_butvar = StringVar()
foc_butvar.set("Button widget")
foc_but = ttk.Button(frame, width = 7, textvariable = foc_butvar)
foc_but.grid(column = 2, row = 1, sticky = (W, E))
# Focus commands
def focus(event):
focused_widget = frame.focus_get()
foc_labvar.set((focused_widget, "has focus"))
print(focused_widget, "has focus")
# Bind mouse click to run focus command
root.bind("<Button-1>", focus)
# Resize widgets inside frame
for child in frame.winfo_children():
child.grid_configure(padx = 5, pady = 5)
root.mainloop()

You can just easily do this having event handle the widget identification part, like:
def focus(event):
focused_widget = event.widget.winfo_class()
foc_labvar.set((focused_widget, "has focus")) # Or f'{focused_widget} has focus'
print(focused_widget, "has focus")
Here event will provide the widget with widget method and then you can use any widget methods on it, like focus() or insert()(if its an entry widget) and so on. Here winfo_class should work, because it is a universal method and works with all the widgets.
More info on winfo_class, it will provide the class of the widget, like TButton for buttons, because that is how tk refers to them. If you adamantly still want to get rid of the T then just go for event.widget.winfo_class()[1:] to trim the 'T' off.

You can give widgets a name of your choosing. You can then use winfo_name to get the name of the widget. About the only required for a name is that it cannot have a period in it.
Also, you should bind to <FocusIn> and <FocusOut> so that your code works even if the focus changes via the keyboard.
foc_ent = ttk.Entry(..., name="foc entry")
foc_but = ttk.Button(..., name="foc button")
...
def focus(event):
focused_widget = frame.focus_get()
if focused_widget:
foc_labvar.set(f"{focused_widget.winfo_name()} as focus")
else:
foc_labvar.set("nothing has focus")
root.bind("<FocusIn>", focus)
root.bind("<FocusOut>", focus)

You can just use an if statement like this:
def focus(event):
focused_widget = frame.focus_get() # You can also use `event.widget` like what #CoolCloud did.
if focused_widget == foc_ent:
foc_labvar.set("Entry has focus")
if focused_widget == foc_but:
foc_labvar.set("Button has focus")

Combining the advice provided. Here is what I've ended up with which is working the way I had imagined in my head plus a little extra from everyone's help:
# Focus commands
def focus(event):
focused_widget = event.widget.winfo_class()[1:]
foc_labvar.set(focused_widget + " has focus")
foc_entvar.set(focused_widget + " has focus")
print(focused_widget, "has focus")
# Bind mouse and keyboard to run focus command
root.bind("<Button-1>", focus)
root.bind("<FocusIn>", focus)
root.bind("<FocusOut>", focus)

Related

Scrolling Text Widget with Mousewheel when filled with Widgets (python, tkinter)

I use a disabled text widget filled with labels, to make a scrollable frame.
This works just fine, except for one thing: when the mouse is over a label, then scrolling the mouse wheel no longer gets registered.
I have below a simple demonstration script, where you will see that you can scroll when the mouse is over an empty part of the text widget, but cannot scroll anymore when you are hovering over a button (in the example I just used buttons, same effect as labels).
So very concretely my question: how can I make the text widget scrollable even when the mouse hovers over a widget?
from tkinter import Tk, Button, Text,Scrollbar
class test:
def __init__(self):
self.win = Tk()
text = Text(self.win, width=40, height=10, wrap = "none")
ys = Scrollbar(self.win, orient = 'vertical', command = text.yview)
text['yscrollcommand'] = ys.set
text.grid(column = 0, row = 0, sticky = 'nwes')
ys.grid(column = 1, row = 0, sticky = 'ns')
for x in range(1,100):
b = Button(text, text='Push Me')
text.window_create("end", window=b)
text.insert("end",'\n')
self.win.mainloop()
test = test()
Ok, I just found an answer. The problem lies, partly, in that there was a difference between working with Linux and Windows when binding Mousewheel to a widget.
So in addition to the above I made this code, to bind the mousewheel to the buttons. Problem solved, albeit, in my opionion, apparently unnecesarily complex. It would be nicer if the Text Widget would still register scrolling despite the presence of other widgets inside of it. :
b = Button(self.text, text="Push Me")
b.bind("<Button-4>", self.on_mousewheel)
b.bind("<Button-5>", self.on_mousewheel)
def on_mousewheel(self,event):
if event.num==4:
self.text.yview("scroll",-1,"units")
else:
self.text.yview("scroll",1,"units")
Update:
self.text.bind_all("<Button-4>", self.on_mousewheel)
self.text.bind_all("<Button-5>", self.on_mousewheel)
works also, so that not every individual Button or Label needs its own binding.

Issue with Combobox

excuse the greeness. Trying to build GUI where option selected from Combobox populates text box. Nothing happening. First time programming so appreciate i have made a lot of errors here.
import tkinter as tk
from tkinter import ttk
from tkinter import scrolledtext
# function to display course selected
def courseDisplay():
box = course.get()
print(box)
# Create instance
win = tk.Tk()
win.resizable(130,130)
win.title("RaceCourse GUI")
# create combobox
course = tk.StringVar()
courseChosen = ttk.Combobox(win,width=60,textvariable=course,state='readonly')
courseChosen['values'] = ("Choose a course","Ascot", "Bath", "Chester")
courseChosen.grid(column=5, row=1,rowspan = 3, columnspan = 3,padx = 300, pady = 40)
courseChosen.current(0)
courseChosen.bind("<<ComboboxSelected>>", courseDisplay)
# create scrolled Text control
scrolW = 46
scrolH = 10
box = scrolledtext.ScrolledText(win, width=scrolW, height=scrolH, wrap=tk.WORD)
box.grid(column=5, row=8, columnspan=3,padx = 300,pady = 10)
# Start GUI
win.mainloop()
Since function courseDisplay is called when some event occurs on combobox (namely, when some option is selected), it should accept one variable (usually called event). So, your function should look like this:
def courseDisplay(event=None):
box = course.get()
print(box)
Of course, You should add another logic for showing test in textbox instead of print.

Python Tkinter: adding a scrollbar to frame within a canvas

I am quite new to Tkinter, but, nevertheless, I was asked to "create" a simple form where user could provide info about the status of their work (this is sort of a side project to my usual work).
Since I need to have quite a big number of text widget (where users are required to provide comments about status of documentation, or open issues and so far), I would like to have something "scrollable" (along the y-axis).
I browsed around looking for solutions and after some trial and error I found something that works quite fine.
Basically I create a canvas, and inside a canvas a have a scrollbar and a frame. Within the frame I have all the widgets that I need.
This is a snipet of the code (with just some of the actual widgets, in particular the text ones):
from Tkinter import *
## My frame for form
class simpleform_ap(Tk):
# constructor
def __init__(self,parent):
Tk.__init__(self,parent)
self.parent = parent
self.initialize()
#
def initialize(self):
#
self.grid_columnconfigure(0,weight=1)
self.grid_rowconfigure(0,weight=1)
#
self.canvas=Canvas(self.parent)
self.canvas.grid(row=0,column=0,sticky='nsew')
#
self.yscrollbar = Scrollbar(self,orient=VERTICAL)
self.yscrollbar.grid(column =4, sticky="ns")
#
self.yscrollbar.config(command=self.canvas.yview)
self.yscrollbar.pack(size=RIGTH,expand=FALSE)
#
self.canvas.config(yscrollcommand=self.yscrollbar.set)
self.canvas.pack(side=LEFT,expand=TRUE,fill=BOTH)
#
self.frame1 = Frame(self.canvas)
self.canvas.create_window(0,0,window=self.frame1,anchor='nw')
# Various Widget
# Block Part
# Label
self.labelVariableIP = StringVar() # Label variable
labelIP=Label(self.frame1,textvariable=self.labelVariableIP,
anchor="w",
fg="Black")
labelIP.grid(column=0,row=0,columnspan=1,sticky='EW')
self.labelVariableIP.set(u"IP: ")
# Entry: Single line of text!!!!
self.entryVariableIP =StringVar() # variable for entry field
self.entryIP =Entry(self.frame1,
textvariable=self.entryVariableIP,bg="White")
self.entryIP.grid(column = 1, row= 0, sticky='EW')
self.entryVariableIP.set(u"IP")
# Update Button or Enter
button1=Button(self.frame1, text=u"Update",
command=self.OnButtonClickIP)
button1.grid(column=2, row=0)
self.entryIP.bind("<Return>", self.OnPressEnterIP)
#...
# Other widget here
#
# Some Text
# Label
self.labelVariableText = StringVar() # Label variable
labelText=Label(self.frame1,textvariable=
self.labelVariableText,
anchor="nw",
fg="Black")
labelText.grid(column=0,row=curr_row,columnspan=1,sticky='EW')
self.labelVariableTexta.set(u"Insert some texts: ")
# Text
textState = TRUE
self.TextVar=StringVar()
self.mytext=Text(self.frame1,state=textState,
height = text_height, width = 10,
fg="black",bg="white")
#
self.mytext.grid(column=1, row=curr_row+4, columnspan=2, sticky='EW')
self.mytext.insert('1.0',"Insert your text")
#
# other text widget here
#
self.update()
self.geometry(self.geometry() )
self.frame1.update_idletasks()
self.canvas.config(scrollregion=(0,0,
self.frame1.winfo_width(),
self.frame1.winfo_height()))
#
def release_block(argv):
# Create Form
form = simpleform_ap(None)
form.title('Release Information')
#
form.mainloop()
#
if __name__ == "__main__":
release_block(sys.argv)
As I mentioned before, this scripts quite does the work, even if, it has a couple of small issue that are not "fundamental" but a little annoying.
When I launch it I got this (sorry for the bad screen-capture):
enter image description here
As it can be seen, it only shows up the first "column" of the grid, while I would like to have all them (in my case they should be 4)
To see all of the fields, I have to resize manually (with the mouse) the window.
What I would like to have is something like this (all 4 columns are there):
enter image description here
Moreover, the scrollbar does not extend all over the form, but it is just on the low, right corner of the windows.
While the latter issue (scrollbar) I can leave with it, the first one is a little more important, since I would like to have the final user to have a "picture" of what they should do without needing to resize the windows.
Does any have any idea on how I should proceed with this?
What am I missing?
Thanks in advance for your help
In the __init__ method of your class, you do not appear to have set the size of your main window. You should do that, or it will just set the window to a default size, which will only show whatever it can, and in your case, only 1 column. Therefore, in the __init__ method, try putting self.geometry(str(your_width) + "x" + str(your_height)) where your_width and your_height are whatever integers you choose that allow you to see what you need to in the window.
As for your scrollbar issue, all I had to do was change the way your scrollbar was added to the canvas to a .pack() and added the attributes fill = 'y' and side = RIGHT to it, like so:
self.yscrollbar.pack(side = 'right', fill = 'y')
Also, you don't need:
self.yscrollbar.config(command=self.canvas.yview)
self.yscrollbar.pack(size=RIGHT,expand=FALSE)
Just add the command option to the creation of the scrollbar, like so:
self.scrollbar = Scrollbar(self,orient=VERTICAL,command=self.canvas.yview)
In all, the following changes should make your code work as expected:
Add:
def __init__(self,parent):
Tk.__init__(self,parent)
self.parent = parent
self.initialize()
# Resize the window from the default size to make your widgets fit. Experiment to see what is best for you.
your_width = # An integer of your choosing
your_height = # An integer of your choosing
self.geometry(str(your_width) + "x" + str(your_height))
Add and Edit:
# Add `command=self.canvas.yview`
self.yscrollbar = Scrollbar(self,orient=VERTICAL,command=self.canvas.yview)
# Use `.pack` instead of `.grid`
self.yscrollbar.pack(side = 'right', fill = 'y')
Remove:
self.yscrollbar.config(command=self.canvas.yview)
self.yscrollbar.pack(size=RIGHT,expand=FALSE)

bring window to top level

I want to present several questions, one after another. The first question is shown as I like, with the cursor set in the entry field. Then I destroy the window and call the function again to create a new window. This time the window is not shown in the front and therefore I first have to click on the screen in order to have the cursor set to the entry field. Also the escape key does not work until I click on the screen to bring the window to the top. I'd be very happy for your help!
Thank you in advance!
Here's my code:
from Tkinter import *
def text_input_restricted(fn,question, nr_letters, limit, len_min, len_max,keys, justify):
class MyApp():
def validate(root, S):
return all(c in keys for c in S)
def __init__(self, q= None):
#save response after "next"-button has been clicked
def okClicked():
lines = e.get()
if len_min < len(lines) < len_max:
lines = unicode(lines).encode('utf-8')
datFile = open(fn, "a")
datFile.write(" '%s'"%(lines))
datFile.close()
self.root.destroy()
self.root = Tk()
vcmd = (self.root.register(self.validate), '%S')
#quit if escape-key has been pressed
self.root.bind('<Escape>', lambda q: quit())
#colors
color = '#%02x%02x%02x' % (200, 200, 200)
self.root.configure(bg=color)
#set window size to screen size
RWidth=MAXX
RHeight=MAXY
self.root.geometry(("%dx%d")%(RWidth,RHeight))
#remove buttons (cross, minimize, maximize)
self.root.overrideredirect(1)
#remove title
self.root.title("")
#item
labelWidget = Label(self.root,text=question, font=("Arial", int(0.02*MAXX)), bd=5, bg=color, justify="center")
labelWidget.place(x=0, y=RHeight/40,width=RWidth)
#"next"-button
ok_width = RWidth/15
ok_height = RWidth/15
okWidget = Button(self.root, text= "next", command = okClicked, font=("Arial",int(0.015*MAXX)), bd=5, justify="center")
okWidget.place(x=RWidth/2-ok_width/2,y=13*RHeight/40, width=ok_width,height=ok_height)
def callback(sv):
c = sv.get()[0:limit]
sv.set(c)
sv = StringVar()
width=nr_letters * int(0.02*MAXX)*1.3
sv.trace("w", lambda name, index, mode, sv=sv: callback(sv))
e = Entry(self.root, textvariable=sv,font=("Arial", int(0.02*MAXX)),justify=justify,validate="key", validatecommand=vcmd)
e.place(x=RWidth/2-width/2, y=9*RHeight/40, width=width)
#show cursor
e.focus_set()
self.root.mainloop()
MyApp()
MAXX=1366
MAXY=768
fn = "D:/test.dat"
text_input_restricted(fn = fn, question=u"f for female, m for male", nr_letters=1, limit =1, len_min =0, len_max=2, keys = 'fm', justify="center")
text_input_restricted(fn = fn, question="How old are you?", nr_letters=2,limit=2, len_min = 1, len_max = 3, keys = '1234567890',justify="center")
In Tk you use the raise command to bring a window to the front of the Z-order. However, raise is a keyword in Python so this has been renamed to lift. Provided your application is still the foreground application you can call the lift() method on a toplevel widget. If the application is not the foreground application then this will raise the window but only above other windows from the same application. On Windows this causes the taskbar icon for your application to start flashing.
You might do better to destroy the contents of the toplevel and replace them. Or even better - create a number of frames holding each 'page' of your application and toggle the visibility of each frame by packing and pack_forgetting (or grid and grid forget). This will avoid loosing the focus completely - you can just set the focus onto the first widget of each frame as you make it visible.

How to delete Tkinter widgets from a window?

I have a list of tkinter widgets that I want to change dynamically.
How to delete the widgets from the window?
You can call pack_forget to remove a widget (if you use pack to add it to the window).
Example:
from tkinter import *
root = Tk()
b = Button(root, text="Delete me", command=lambda: b.pack_forget())
b.pack()
root.mainloop()
If you use pack_forget, you can later show the widget again calling pack again. If you want to permanently delete it, call destroy on the widget (then you won't be able to re-add it).
If you use the grid method, you can use grid_forget or grid_remove to hide the widget.
One way you can do it, is to get the slaves list from the frame that needs to be cleared and destroy or "hide" them according to your needs. To get a clear frame you can do it like this:
from tkinter import *
root = Tk()
def clear():
list = root.grid_slaves()
for l in list:
l.destroy()
Label(root,text='Hello World!').grid(row=0)
Button(root,text='Clear',command=clear).grid(row=1)
root.mainloop()
You should call grid_slaves(), pack_slaves() or slaves() depending on the method you used to add the widget to the frame.
You simply use the destroy() method to delete the specified widgets like this:
lbl = tk.Label(....)
btn = tk.Button(....., command=lambda: lbl.destroy())
Using this you can completely destroy the specific widgets.
You say that you have a list of widgets to change dynamically. Do you want to reuse and reconfigure existing widgets, or create all new widgets and delete the old ones? It affects the answer.
If you want to reuse the existing widgets, just reconfigure them. Or, if you just want to hide some of them temporarily, use the corresponding "forget" method to hide them. If you mapped them with pack() calls, you would hide with pack_forget() (or just forget()) calls. Accordingly, grid_forget() to hide gridded widgets, and place_forget() for placed widgets.
If you do not intend to reuse the widgets, you can destroy them with a straight destroy() call, like widget.destroy(), to free up resources.
clear_btm=Button(master,text="Clear") #this button will delete the widgets
clear_btm["command"] = lambda one = button1, two = text1, three = entry1: clear(one,two,three) #pass the widgets
clear_btm.pack()
def clear(*widgets):
for widget in widgets:
widget.destroy() #finally we are deleting the widgets.
Today I learn some simple and good click event handling using tkinter gui library in python3, which I would like to share inside this thread.
from tkinter import *
cnt = 0
def MsgClick(event):
children = root.winfo_children()
for child in children:
# print("type of widget is : " + str(type(child)))
if str(type(child)) == "<class 'tkinter.Message'>":
# print("Here Message widget will destroy")
child.destroy()
return
def MsgMotion(event):
print("Mouse position: (%s %s)" % (event.x, event.y))
return
def ButtonClick(event):
global cnt, msg
cnt += 1
msg = Message(root, text="you just clicked the button..." + str(cnt) + "...time...")
msg.config(bg='lightgreen', font=('times', 24, 'italic'))
msg.bind("<Button-1>", MsgClick)
msg.bind("<Motion>", MsgMotion)
msg.pack()
#print(type(msg)) tkinter.Message
def ButtonDoubleClick(event):
import sys; sys.exit()
root = Tk()
root.title("My First GUI App in Python")
root.minsize(width=300, height=300)
root.maxsize(width=400, height=350)
button = Button(
root, text="Click Me!", width=40, height=3
)
button.pack()
button.bind("<Button-1>", ButtonClick)
button.bind("<Double-1>", ButtonDoubleClick)
root.mainloop()
Hope it will help someone...
You can use forget method on the widget
from tkinter import *
root = Tk()
b = Button(root, text="Delete me", command=b.forget)
b.pack()
b['command'] = b.forget
root.mainloop()
I found that when the widget is part of a function and the grid_remove is part of another function it does not remove the label. In this example...
def somefunction(self):
Label(self, text=" ").grid(row = 0, column = 0)
self.text_ent = Entry(self)
self.text_ent.grid(row = 1, column = 0)
def someotherfunction(self):
somefunction.text_ent.grid_remove()
...there is no valid way of removing the Label.
The only solution I could find is to give the label a name and make it global:
def somefunction(self):
global label
label = Label(self, text=" ")
label.grid(row = 0, column = 0)
self.text_ent = Entry(self)
self.text_ent.grid(row = 1, column = 0)
def someotherfunction(self):
global label
somefunction.text_ent.grid_remove()
label.grid_remove()
When I ran into this problem there was a class involved, one function being in the class and one not, so I'm not sure the global label lines are really needed in the above.

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