Waiting Screen while data is being extracted from an API - python-3.x

I have created a Python Script to download data using an API. And I have put a simple GUI on top of it as well using PySimpleGUI.
However, while the data is being downloaded, I want to show a indeterminate progressbar or something like that, which will exit on its own after the download completes.
Is there any way to implement this requirement?

Two ways easily for it, element sg.ProgressBar or simple sg.Text with different length of string, maybe █, to show the state of progress.
Demo_Progress_Meters
or
from random import randint
import PySimpleGUI as sg
sg.theme('DarkBlue')
layout = [[sg.Text('', size=(50, 1), relief='sunken', font=('Courier', 11),
text_color='yellow', background_color='black',key='TEXT')]]
window = sg.Window('Title', layout, finalize=True)
text = window['TEXT']
state = 0
while True:
event, values = window.read(timeout=100)
if event == sg.WINDOW_CLOSED:
break
state = (state+1)%51
text.update('█'*state)
window.close()
Note: remember to use monospaced font, otherwise the length of sg.Text will be different as length of state string.
Depend on progress of job to set state of progress.

Related

PySimpleGUI - not show background when window change

In my application I have multiple windows that change based on events(one close and another open) and show only one window at a time. During one window close and another open its take some time since fetch data from database and prepare for window.
Here problem is that during the time of one window close and another open user can see and feel that one is being open and another is being close by seeing the background.
What I want, until second screen is not fully loaded, first window be visible on the screen.
My current code is something like,
import PySimpleGUI as sg
layout = [[sg.Button('Users', key='show_user_list')]]
window = sg.Window('users').Layout(layout)
while True:
event, values = window.Read()
if event == 'show_user_list':
window.Close()
# code ommited here for simplicity
# do mysql stuff to fetch data
# layout2 = ...
# window2 = sg.Window('user listing').Layout(layout2)
# while True:
# event, values = window2.Read()
# ...
# like that I have multiple windows
else:
pass
How I can give users feel like the window content is changing not one window closes and another opens?
Sure, you can make sure the background is not seen by first opening your Window 2, which will be created on top of Window 1, THEN closing your Window 1.
To do this, add a .Finalize() onto the Window 2 creation. This will cause the window to immediate show up. Then on the next line, close Window 1.
import PySimpleGUI as sg
layout = [[sg.Button('Users', key='show_user_list')]]
window = sg.Window('users').Layout(layout)
while True:
event, values = window.Read()
if event == 'show_user_list':
# code ommited here for simplicity
# do mysql stuff to fetch data
# layout2 = ...
# window2 = sg.Window('user listing').Layout(layout2).Finalize()
# window.Close()
# while True:
# event, values = window2.Read()
# ...
# like that I have multiple windows
else:
pass
The key to making this kind of window update work is to create the windows at the same location. The default is to make windows that are centered on the screen. This means if your windows are not the same size then you'll likely notice a small "blip" as you change from one to the other. But it shouldn't look bad because it'll happen so quickly.
If you really want to get fancy, you can add another step which will make the switch between the windows even smoother. This new step involves creating window 2 with Alpha=0, meaning that it's invisible, then after it's fully formed (using Finalize()) you change the Alpha to 1 which will make the window appear.
import PySimpleGUI as sg
layout = [[sg.Text('Example of window-replacement')],
[sg.Combo(['abdeffg', 'rrrfwwew'], size=(10, 4))],
[sg.B('Enable Filter'), sg.B('Warning'), sg.B('Reopen')],]
window = sg.Window('My Text Editor', layout)
while True: # Event Loop
event, values = window.Read()
if event is None:
break
print(event, values)
if event == 'Reopen':
layout2 = [[sg.Text('This is a completely different window')],
[sg.Combo(['abdeffg', 'rrrfwwew'], size=(10, 4))],
[sg.B('Enable Filter'), sg.B('Warning'), sg.B('Reopen')], ]
window2 = sg.Window('My Text Editor', layout2, alpha_channel=0).Finalize()
window2.SetAlpha(1)
window.Close()
window = window2
window.Close()
This removed some of the "painting" of the window that I was seeing. That shouldn't happen because I use this same trick when creating the window to begin with. Alpha is used to hide the window while it's being created.

Ever expanding amount of Entries with TKinter

What I'm trying to do is to make a GUI where when you start typing in an entry-box another shows up just beneath the one you are typing in. Then when you start typing in the one that popped up, another pops up. Is this possible with TKinter and Python?
Edit:
So what I currently have is this:
entry1 = StringVar()
numberLabel3 = Label(window, text = "3. External meeting attendees")
r+=1
numberLabel3.grid(column = 0, row = r, sticky = W)
externalAtendeesLabel = Label(window, text = "input name of external meeting atendee: ")
r+=1
externalAtendeesLabel.grid(column = 1, row = r, sticky = E)
externalAtendeesEntry = Entry(window, textvariable = entry1)
externalAtendeesEntry.grid(column = 2, row = r)
#Note to self: Find a smart way of dynamically expanding this "list" of entries
(There is more code above and below this, but this is the relevant code for my question)
where r is a variable I made to make it easier to insert stuff into the middle of my rather long code.
The imports I'm using are:
from tkinter import *
from PIL import ImageTk
from PIL import Image
import os
I use the image modules and OS to insert an image further up in my GUI.
What I was thinking was to make a function that I could somehow setup to check the newest Entry-box, but I've run into the problem that for this to be potentially infinite I would have to dynamically create new variables, so that I can access the information that the user inputs. These variables would save the info just like my entry1 variable does it for the externalAtendeesEntry.
I would also have to dynamically make variables for more entries.
How do I dynamically create a potentially infinite amount of variables?
I know that this is kind of a re-post, but the other ones I've found all say that you should use dictionaries, but in that case it can't be infinite. It can only be finite to the point where my dictionary is no longer.
For one, you don't need to use StringVar. It only complicates your code without providing any real value. The other part of the answer is to store the entries in a list.
For example, create a function called addEntry that creates an entry and adds it to a list:
entries = []
...
def addEntry():
entry = tk.Entry(...)
entry.pack(...)
entries.append(entry)
To get the values at a later date, just iterate over the list:
for entry in entries:
print(entry.get())
With that, you can add entries whenever you want. You could, for example, bind to <Any-KeyRelease> to create a new entry as the user types (being sure to only do it if there isn't already a blank entry). Or, bind to <Return> or <FocusOut>, or on the click of a "new person" button, or however else you decide.

Tkinter Entry widget color fading

In my new application I want when the mouse is over the entry() widget to change color (this I know how to do it) but I want the color to change gradually, not immediately.
This is my code:
# User_Line Focus In/Out
def User_Line_Focus_In(self, event):
self.User_Line.configure(bg = "#DCDCDC")
def User_Line_Focus_Out(self, event):
self.User_Line.configure(bg = "#FFFFFF")
You need to create a method which increments the colour and you need to use tkinter's after which registers an alarm callback that is called after a given time. You then need to reference it recursively in order to get the fading effect you want.
def incrementHex(hex_str, increment): #with hex_str in format "#FFFFFF" or any colour
red = int(hex_str[1:3],16) #specifies base for integer conversion
green = int(hex_str[3:5],16)
blue = int(hex_str[5:],16)
red += increment #increment can be negative
green += increment
blue += increment
new_hex_str = "#" + str(hex(red)) + str(hex(blue)) + str(hex(green))
return new_hex_str
def Fade(self, start_hex, increment):
new_hex = self.incrementHex(start_hex, increment)
self.User_Line.configure(bg = new_hex)
#where self.master is the parent widget as defined in the __init__ method...
self.master.after(50,lambda: self.Fade(new_hex, increment)) #or any time interval in milliseconds
#you'll probably need some code to stop it fading here, but I'll let you tackle that one :)
def User_Line_Focus_In(self, event):
self.Fade("#FFFFFF",-1) #could be any colour and increment
I haven't been able to test it, but I think it should work in principle. An extension of this would be to have different increments for red, green and blue.
I think you are going to have to pull up your socks on this one and do some coding (tkinter doesn't have this built in)
So what you are looking for is :
An algorithm to go from color one to color two and get intermediate colors. (Hex values are just numbers in base 16 but they can be added or subtracted like normal numbers)
The simplest solution would be to just run the algorithm (color_difference here)
def fade_colors(event, new_color):
old_color = event.widget.cget('bg')
for color in color_difference(old_color, new_color):
event.widget.configure(color)
time.sleep(0.1)
widget.bind('<Enter>', lambda event: fade_colors(event, color))
You might also like to cancel the operation if the user leaves the widget. Take a look at the built in sched module.
If you find your gui becomes unresponsive during the fading you could consider using the after method, you can read this excellent blog post on non blocking gui techniques in python and tkinter. This may not be an issue if you cancel the callback as soon as the user leaves the widget (thus freeing up tkinter to handle his other actions)

Continually running functions in tkinter after mainloop in Python 3.4

What I want to do is colour in a single pixel in the centre of the screen, then at random choose an adjacent pixel and colour it in, and then repeat until some condition is met - anything such as time, or the screen is full, or after a certain number of pixels are full. This ending isn't too important, I haven't got that far yet, and I think I could manage to work that out myself.
I have no experience with tkinter, but I decided it was the best way to display this, since I don't really no any other way. Some of this code (mainly the tkinter functions like Canvas, PhotoImage etc) is therefore copy-pasted (and slightly edited) from examples I found here.
What my code does when run is hard to tell - it uses the CPU as much as it can seemingly indefinitely, and slowly increases its memory usage, but doesn't appear to do anything. No window opens, and the IDLE interpreter goes to a blank line, as usual when calculating something. When killed, the window opens, and displays a white page with a little black blob in the bottom right corner - as if the program had done what it was meant to, but without showing it happening, and starting in the wrong place.
So:
Why does it do this?
What should I do to make my program work?
What would be a better way of coding this, changing as many things as you like (ie. no tkinter, a different algorithm etc)?
from tkinter import Tk, Canvas, PhotoImage, mainloop
from random import randrange
from time import sleep
def choose_pixel(pixel_list):
possible_pixels = []
for x in pixel_list:
#adjacent pixels to existing ones
a = [x[0] + 1, x[1]]
b = [x[0] - 1, x[1]]
c = [x[0], x[1] + 1]
d = [x[0], x[1] - 1]
#if a not in pixel_list:
possible_pixels.append(a)
#if b not in pixel_list:
possible_pixels.append(b)
#if c not in pixel_list:
possible_pixels.append(c)
#if d not in pixel_list:
possible_pixels.append(d)
pixel_choosing = randrange(len(possible_pixels))
final_choice = possible_pixels[pixel_choosing]
return final_choice
def update_image(img_name, pixel):
img.put("#000000", (pixel[0], pixel[1]))
WIDTH, HEIGHT = 320, 240
window = Tk()
#create white background image
canvas = Canvas(window, width=WIDTH, height=HEIGHT, bg="#ffffff")
canvas.pack()
img = PhotoImage(width=WIDTH, height=HEIGHT)
canvas.create_image((WIDTH, HEIGHT), image=img, state="normal")
first_pixel = [int(WIDTH/2), int(HEIGHT/2)]
pixel_list = [first_pixel]
img.put("#000000", (first_pixel[0], first_pixel[1]))
canvas.pack()
runs = 0
while True:
next_pixel = choose_pixel(pixel_list)
pixel_list.append(next_pixel)
window.after(0, update_image, img, next_pixel)
canvas.pack()
runs+=1
window.mainloop()
The pattern for running something periodically in tkinter is to write a function that does whatever you want it to do, and then the last thing it does is use after to call itself again in the future. It looks something like this:
import tkinter as tk
...
class Example(...):
def __init__(self, ...):
...
self.canvas = tk.Canvas(...)
self.delay = 100 # 100ms equals ten times a second
...
# draw the first thing
self.draw_something()
def draw_something(self):
<put your code to draw one thing here>
self.canvas.after(self.delay, self.draw_something)
After the function draws something, it schedules itself to run again in the future. The delay defines approximately how long to wait before the next call. The smaller the number, the faster it runs but the more CPU it uses. This works, because between the time after is called and the time elapses, the event loop (mainloop) is free to handle other events such as screen redraws.
While you may think this looks like recursion, it isn't since it's not making a recursive call. It's merely adding a job to a queue that the mainloop periodically checks.

Separate user interaction from programmical change: PyQt, QComboBox

I have several QComboBoxes in my PyQt4/Python3 GUI and they are filled with some entries from a database during the initialisation. Initial CurrentIndex is set to 0. There is also a tick box which changes the language of the items in my combo boxes. To preserve current user selection I backup index of the current item and setCurrentIndex to this number after I fill in ComboBox with translated items. All those actions emit currentIndexChanged signal.
Based on the items selected in QComboBoxes some plot is displayed. The idea is to redraw the plot online - as soon as the user changes any of ComboBox current item. And here I have a problem since if I redraw the plot every time signal currentIndexChanged is emited, I redraw it also several times during initialization and if the translation tick box selection was changed.
What is the best way to separate these cases? In principle I need to separate programmical current Index Change from the user, and update the plot only in the later case (during GUI initialisation I can programically call update plot function once). Should I write/rewrite any signal? If so, I never did that before and would welcome any hint or a good example. Use another signal? Or maybe there is a way to temporary block all signals?
There are a few different things you can try.
Firstly, you can make sure you do all your initialization before you connect up the signals.
Secondly, you could use the activated signal, which is only sent whenever the user selects an item. (But note that, unlike currentIndexChanged, this signal is sent even if the index hasn't changed).
Thirdly, you could use blockSignals to temporarily stop any signals being sent while the current index is being changed programmatically.
Here's a script that demonstrates these possibilities:
from PyQt4 import QtGui, QtCore
class Window(QtGui.QWidget):
def __init__(self):
QtGui.QWidget.__init__(self)
layout = QtGui.QVBoxLayout(self)
self.combo = QtGui.QComboBox()
self.combo.setEditable(True)
self.combo.addItems('One Two Three Four Five'.split())
self.buttonOne = QtGui.QPushButton('Change (Default)', self)
self.buttonOne.clicked.connect(self.handleButtonOne)
self.buttonTwo = QtGui.QPushButton('Change (Blocked)', self)
self.buttonTwo.clicked.connect(self.handleButtonTwo)
layout.addWidget(self.combo)
layout.addWidget(self.buttonOne)
layout.addWidget(self.buttonTwo)
self.changeIndex()
self.combo.activated['QString'].connect(self.handleActivated)
self.combo.currentIndexChanged['QString'].connect(self.handleChanged)
self.changeIndex()
def handleButtonOne(self):
self.changeIndex()
def handleButtonTwo(self):
self.combo.blockSignals(True)
self.changeIndex()
self.combo.blockSignals(False)
def changeIndex(self):
index = self.combo.currentIndex()
if index < self.combo.count() - 1:
self.combo.setCurrentIndex(index + 1)
else:
self.combo.setCurrentIndex(0)
def handleActivated(self, text):
print('handleActivated: %s' % text)
def handleChanged(self, text):
print('handleChanged: %s' % text)
if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
window = Window()
window.show()
sys.exit(app.exec_())

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