Is it possible to have a slider (Scale widget in tkinter) where the possible values that are displayed when manipulating the slider are discrete values read from a list?
The values in my list are not in even steps and are situation dependent.
From all the examples I've seen, you can specify a minimum value, a maximum value and a step value (n values at a time), but my list might look like this:
list=['0', '2000', '6400', '9200', '12100', '15060', '15080']
Just as an example. To reiterate, I want it go from for instance list[0] to list[1] or list[6] to list[5] when pulling the slider.
If anyone has any other suggestion for easily being able to pick a value from hundreds of items in a list, I'm all ears. I tried the OptionMenu widget but it gets to extensive and hard get a view of.
Edit you could set the command of the slider to a callback, have that callback compare the current value to your list and then jump to the nearest by calling set() on the slider
so:
slider = Slider(parent, from_=0, to=100000, command=callback)
and:
def callback(event):
current = event.widget.get()
#compare value here and select nearest
event.widget.set(newvalue)
Edit:
to show a complete (but simple example)
try:
import tkinter as tk
except ImportError:
import Tkinter as tk
valuelist = [0,10,30,60,100,150,210,270]
def valuecheck(value):
newvalue = min(valuelist, key=lambda x:abs(x-float(value)))
slider.set(newvalue)
root = tk.Tk()
slider = tk.Scale(root, from_=min(valuelist), to=max(valuelist), command=valuecheck, orient="horizontal")
slider.pack()
root.mainloop()
i've tested this in python 2.7.6 and 3.3.2, even when dragging the slider this jumps to the nearest value to where the mouse is currently as opposed to only jumping when you let go of the slider.
Related
I'm trying to change the color of text in a text widget similar to how a VS code changes the code colors:
Like this:
To do this I have a Text widget and I have a function handleCodeEditor bound to <KeyRelease> that will split the text widget's contents by row and then conditionally modify text colors. To make the process less exhaustive I would like to only modify the current row, but I am not aware of any method that would give me the row number.
Any ideas?
def getrow(event):
index = textbox.index(INSERT)
row = index.split(".")[0]
print(row)
root = Tk()
textbox = Text(root)
textbox.bind("<KeyRelease>",getrow)
textbox.pack()
root.mainloop()
This function will print the current line number whenever a key is released.
Hope this is what you're after.
Sorry for the vague title but I didn't know how to explain myself better. Basically what I try to do in tkinter here is adding and removing labels. The label value gets updated so that I always have an increment of 1 even though I deleted a label in the beginning. If I generate labels and delete them from the bottom up I have no problems but it I delete one from the middle and then try to clean my list I get an error:
Exception in Tkinter callback
Traceback (most recent call last):
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk/Tkinter.py", line 1536, in __call__
return self.func(*args)
File "/Users/XXXX/Helper/development/dynamicListLabels.py", line 21, in <lambda>
labelList[index].append(ttk.Button(root, text="Remove", command=lambda: removeLabel(labelList[index][0], index)))
IndexError: list index out of range
My python code looks like this:
#!/usr/bin/python
from Tkinter import *
import ttk
def removeLabel(labelToRemove, bla):
labelList[labelToRemove.get()][1].destroy()
labelList[labelToRemove.get()][2].destroy()
del labelList[labelToRemove.get()]
for label in labelList:
index = labelList.index(label)
label[0].set(index)
def addNewLabel():
labelList.append([IntVar()])
index = len(labelList) - 1
labelList[index][0].set(index)
labelList[index].append(ttk.Label(root, textvariable=labelList[index][0]))
labelList[index].append(ttk.Button(root, text="Remove", command=lambda: removeLabel(labelList[index][0], index)))
labelList[index][1].grid(column=0)
labelList[index][2].grid(column=1, row=labelList[index][1].grid_info()['row'])
root = Tk()
labelList = []
ttk.Button(root, text="add label", command=addNewLabel).grid(column=1, row=0)
root.mainloop()
And my GUI looks like this:
Thanks for your help!
Design
The main problem comes when dealing with different indexes. Trying to manipulate them carefully leads to complicated operations resulting in a long and inefficient code. To remedy to this problem, we simply get rid of them and take advantage of the label class variable Tkinter.IntVar() you already are using. This gives us full control of the labels and associated widgets.
An other efficient decision to take that prevents from getting lot of headache is to attach each (label, button) couple widgets to a unique Tkinter.Frame() instance. This offers the advantage of deleting the frame using destroy() method leading automatically to the destruction of the widgets it contains. In the same time, this keeps the look of your GUI and makes your it scalable as it offers you the possibility to add more widgets.
Designing addNewLabel()
There is nothing new here compared to your original code except, as I said in 2. each (label, button) couple will be drawn into a single and unique Tkinter.Frame() instance. Of course, the list frames must be declared global in this method.
Designing removeLabel()
From 1. the only argument we need to pass to removeLabel() is the Tkinter variable (var in the code below) inherent to the label we want to get rid of.
We need then to loop over list of frames (frames in the code below) using winfo_children() to seek for the label which has the text variable we are looking for.
Note that because I draw the label before the button inside individual frames, winfo_children() returns as first widget list element the label
winfo_children():
Returns a list containing the path names of all the children of window. Top-level windows are returned as children of their logical
parents. The list is in stacking order, with the lowest window first,
except for Top-level windows which are not returned in stacking order.
Use the wm stackorder command to query the stacking order of Top-level
windows.
This is why it is correct to write : if frame.winfo_children()[0].var == var and destroy the frame that contains the label which satisfies this condition.
Solution
Here is the program. I commented the lines which I think deserve to be commented:
'''
Created on Jun 25, 2016
#author: billal begueradj
'''
from Tkinter import *
import ttk
def removeLabel(var):
global frames
z = -1
# Loop over the list of rames
for frame in frames:
z = z + 1
# Check the text variable of the label of this frame
if frame.winfo_children()[0].var == var:
# Destroy the related frame
frame.destroy()
# Update the size of the list of frames
frames = frames[:z] + frames[z+1:]
# Do not forget to always rest this flag back to -1
z = -1
# Update the labels' numbers
r = 0
for frame in frames:
frame.winfo_children()[0].var.set(r)
r = r + 1
def addNewLabel():
global frames, i
var = IntVar()
frame = Frame(root)
i = i + 1
frame.grid(row=i, column=0)
var.set(len(frames))
l = ttk.Label(frame, textvariable=var)
l.grid(row=0, column=0)
l.var = var
b = ttk.Button(frame, text="Remove", command=lambda: removeLabel(var))
b.grid(row=0, column=1)
frames.append(frame)
if __name__ == '__main__':
root = Tk()
frames = []
i = 1
ttk.Button(root, text="add label", command=addNewLabel).grid(column=0, row=0)
root.mainloop()
Demo
Let us create 6 labels:
Now let us delete the label number 3. You can see that the numbering of the labels is automatically updated:
Now let us add a new label. You can see the newly added label has a number which is consecutive to the last existing label number in the list:
Note that the length of the list is updated all the time as you wanted.
I have a game board which is rows x columns list.
Min size is 2x2 and max 10x10, with unequal rows:columns being okay (e.g. 2x3, 4x9).
Main window object has no predetermines geometry size setting, and widgets (buttons) are being .grid() in it for each list element in a was that creates a 2D map.
Ideally, given the method used this would lead to a nice, edge=to-edge map inside the main window.
Unfortunately, testing has shown that while this is true for maps with columns count > 3, when columns <= 3 then the window seems to default to a certain X-size, where this ugly free space is present at the right of the window.
This is not the case for Y-axis, which is defined by rows.
Note that buttons placed are fixed 32x32 px (determined by image inside).
def createMap (): #creates rows x columns 2D list - a map
global rowsEntryVar, columnsEntryVar, mapList
mapList = []
for row in range(rowsEntryVar):
tempList = []
for column in range(columnsEntryVar):
tempList.append(Button(root, bd=0, bg=redMagenta, activebackground=redMagenta))
mapList.append(tempList)
and then:
def drawMap ():
global mapList
for row in range(len(mapList)):
for column in range(len(mapList[row])):
mapList[row][column].grid(row=row, column=column)
Image:
Image showing the problem
Please go easy on me, I'm quite new to programming. :)
This appears to be a platform-specific limitation. I can't duplicate the problem on my Mac, but I can on a windows VM. Apparently, Windows won't allow the width of the window to be smaller than the space required for the buttons and icon on the titlebar.
My advice is to give the rows and columns a positive weight so that they will grow to fit the window, and then use the sticky option to cause the buttons to fill the space given to them.
when columns <= 3 then the window seems to default to a certain X-size,
Tkinter defaults to the size of the widgets so you must be setting the geometry for "root" somewhere. The following works fine on my Slackware box (and using a function as a function eliminates the globals). If you are just starting, then it is good to form good habits, like conforming to the Python Style Guide https://www.python.org/dev/peps/pep-0008/ (variables and functions are all lower case with underlines).
from Tkinter import *
def create_map (rowsEntryVar, columnsEntryVar): #creates rows x columns 2D list - a map
mapList = []
for row in range(rowsEntryVar):
tempList = []
for column in range(columnsEntryVar):
tempList.append(Button(root, text="%s-%s" % (row, column),
bd=0, bg="magenta2", activebackground=r"magenta3"))
mapList.append(tempList)
return mapList
def draw_map(mapList):
for row in range(len(mapList)):
for column in range(len(mapList[row])):
mapList[row][column].grid(row=row, column=column)
root = Tk()
map_list=create_map(4, 3)
draw_map(map_list)
root.mainloop()
I have a grid in a tkinter frame which displays query results. It has a date field that is changed manually and then date is used as a parameter on the query for those results. every time the date is changed, obviously the results change, giving a different amount of rows. The problem is that if you get less rows the second time you do it, you will still have results from the first query underneath those and will be very confusing.
My question is, how can i remove all rows from the frame that have a row number greater than 6 (regardless of what's in it)?
By the way, I'm running Python 3.3.3. Thanks in advance!
Calling the method grid_forget on the widget will remove it from the window -
this example uses the call grid_slaves on the parent to findout all
widgets mapped to the grid, and then the grid_info call to learn about
each widget's position:
>>> import tkinter
# create:
>>> a = tkinter.Tk()
>>> for i in range(10):
... label = tkinter.Label(a, text=str(i))
... label.grid(column=0, row=i)
# remove from screen:
>>> for label in a.grid_slaves():
... if int(label.grid_info()["row"]) > 6:
... label.grid_forget()
I am getting problems with Tkinter after() method.
Actually, what I want to do is to change the background colour of some entry boxes as soon as times passes. Let's take this piece of code (which is different from the script I'm working on, but the situation described is the same):
import Tkinter as tk
root = tk.Tk()
root.option_add("*Entry.Font","Arial 32 bold")
emptyLabel=tk.Label()
emptyLabel.grid(row=4) #Empty label for geometry purpose
entryList=[]
for x in range(4):
entryList.append([])
for y in range(4):
entryList[x].append('')
entryList[x][y]=tk.Entry(root, bg="white",width=2,justify="center",
takefocus=True,insertofftime=True)
entryList[x][y].grid(row=x,column=y)
solvebt=tk.Button(root,text='Solve').grid(row=5,column=2)
newgamebt=tk.Button(root,text='New').grid(row=5,column=1)
#BROKEN PART STARTS HERE
def changebg(x,y):
entryList[x][y]['bg']='yellow'
for x in range(4):
for y in range(4):
entryList[x][y].after(300,changebg(x,y))
#Same result with root.after(300,changebg(x,y))
root.mainloop()
The problem is that when I start the program, I would expect it to show me as it "paints", one at time, all of the entry boxes in yellow. What happens, instead, is that the program freezes for (300*16) milliseconds and then, all of a sudded, every entry boxes is yellow!
The problem is here:
def changebg(x,y):
entryList[x][y]['bg']='yellow'
for x in range(4):
for y in range(4):
entryList[x][y].after(300,changebg(x,y))
#Same result with root.after(300,changebg(x,y))
You're calling changebg to immediately in the double for loop -- You're then passing the return value (None) to root.after. This won't lead to the delay that you describe. Perhaps your actual code looks like:
for x in range(4):
for y in range(4):
entryList[x][y].after(300,lambda x=x,y=y : changebg(x,y))
That will lead to the behavior you actually describe. Ultimately, what you need is to flatten your list of widgets and then pass then one at a time -- registering the next one if it exists:
import itertools
all_entries = itertools.chain.from_iterable(entryList)
def changebg(ientries):
ientries = iter(ientries) #allow passing a list in as well ...
entry = next(ientries,None)
if entry is not None:
entry['bg'] = 'yellow' #change the color of this widget
root.after(300,lambda : changebg(ientries)) #wait 300ms and change color of next one.
changebg(all_entries)