Develop Reference

How to open a program os.system only using python 3

I am programming a gui using tkinter. I use os.system('file extension'). when I click the button on the gui it should open the next program, but it wont because of python 2. I can use terminal and have pythem3 ./mixed_drink, and this works. Can I set up the code to make the program only run in python 3??
from tkinter import *
import os
##############
root = Tk()
root.title('GET YO DRANK MAIN ')
root.geometry("800x400")
def open_mixed_drinks():
os.system("/home/pi/mixed_drinks.py")

If I understand your question properly, try os.system("python3 /home/pi/mixed_drinks.py")
This way you are passing the .py file to the default installed python3 binary on your system, rather than the global default python which may still be 2.7 on many systems

How to create a file dialog that returns file paths for both selected files AND directories?

I'm trying to use QFileDialog to get a list of the paths of selected folders AND directories.
I know how to do one or the other using QFileDialog.getOpenFileNames and QFileDialog.getExistingDirectory, but not both at the same time.
The C++ docs and other questions elsewhere didn't seem to help me no matter how much I googled.
I am using PyQt5 5.14.2 and Python 3.8.2 on Windows.
Edit:
I've managed to conjure up the following solution not using the native Windows dialog and it works but seems 'hacky'. Can anyone think of a better solution?
from PyQt5 import QtWidgets
main_window = QtWidgets.QApplication([])
dlg = QtWidgets.QFileDialog()
dlg.setFileMode(QtWidgets.QFileDialog.Directory)
dlg.setOption(QtWidgets.QFileDialog.DontUseNativeDialog, True)
_list = dlg.findChild(QtWidgets.QListView, 'listView')
if _list:
_list.setSelectionMode(QtWidgets.QAbstractItemView.MultiSelection)
tree = dlg.findChild(QtWidgets.QTreeView, 'treeView')
if tree:
tree.setSelectionMode(QtWidgets.QAbstractItemView.MultiSelection)
selected = None
if dlg.exec():
selected = dlg.selectedFiles()
print(selected)

There is a bug opened several years ago asking for this feature. Feel free to vote for it to get the attention of Qt developers

does not show icons

I just installed Python3 (3.5.2) and Pyqt5 (5.8.2) and I am following this tutorial to learn and make a GUI: http://zetcode.com/gui/pyqt5/firstprograms/
I'm trying to run the 2nd example but program is returning an error (which also happened on the 1st one, but since it had no image i took no notice) which is the following:
QApplication: invalid style override passed, ignoring it.
No XVisualInfo for format QSurfaceFormat(version 2.0, options QFlags<QSurfaceFormat::FormatOption>(), depthBufferSize -1, redBufferSize 1, greenBufferSize 1, blueBufferSize 1, alphaBufferSize -1, stencilBufferSize -1, samples -1, swapBehavior QSurfaceFormat::SwapBehavior(SingleBuffer), swapInterval 1, profile QSurfaceFormat::OpenGLContextProfile(NoProfile))
Falling back to using screens root_visual.
What is the meaning of this? Am i missing some packages?
I installed pyqt first with this command:
sudo -H pip3 install PyQt5
but Python3 was not acknowledging its existence so i searched the apt ubuntu repos and installed with:
sudo apt install python3-PyQt5
I also tried to reference the image by full path /foo/bar/image.png and nothing
What is the problem?
EDIT #1
The code that i am using is from example 2:
#!/usr/bin/python3
# -*- coding: utf-8 -*-
"""
ZetCode PyQt5 tutorial
This example shows an icon
in the titlebar of the window.
author: Jan Bodnar
website: zetcode.com
last edited: January 2015
"""
import sys
import os
from PyQt5.QtWidgets import QApplication, QWidget
from PyQt5.QtGui import QIcon
base_dir = os.path.dirname(os.path.abspath(__file__))
os.chdir(base_dir)
class Example(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.setGeometry(300, 300, 300, 220)
self.setWindowTitle('Icon')
self.setWindowIcon(QIcon('image.png'))
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
After your post i reinstalled all my packages. The error is slightly different but the result is the same:
python3 example_02.py
QApplication: invalid style override passed, ignoring it.
Screencapture:

Notice that you are having no icons at all for all applications, not just for the PyQt icon example. This is because by default, certain environments turn off the icons in the titlebar. You have to enable them.
For instance in Xfce Desktop Environment, we can use the xfce4-settings-editor tool. In Settings/Settings Editor select xfwm4.
Find the show_app_icon option and check it. Change a theme back and forth to see the changes; they are not visible right away.
After this, you will see the icon in the titlebar of the PyQt5 example.
As for the warning; it is a recent thing and it has to do something
with the incopatibilities between Qt and GTK theming. I have not found
a solution to remove the warning so far.

So first off, you have no errors in your code. That's more akin to a warning but not even. What the following line is telling you
QApplication: invalid style override passed, ignoring it
is that your style option is invalid. If that were an error your script wouldn't run at all.
What I see right off the bat is this, you never supply a path to your image.
Now if the image is in the same root directory as the script then it should recognize said image without a path. But if you're attempting to do what I think you are it wouldn't work like that anyway. I think you're trying to create a launcher icon as well as a title bar icon, which typically goes hand in hand.
It appears to me that you've added it to Atom as some form of resource file. In which case most Ide's create a path for that file. Sometimes it's a path, other times a local url. QT its self does both when working with the QT creator.
I've never used Atom so I can't tell you how that works.
What I can say is this. you're using Linux which means .ico files are useless. I told you before linux doesn't handle icon files the same way windows does. This is most likely your problem.
So I sugesst you take a look at this
https://askubuntu.com/questions/476981/how-do-i-make-a-desktop-icon-to-launch-a-program
After you read that take a look at this if you have to https://help.ubuntu.com/community/UnityLaunchersAndDesktopFiles#Using_a_text_editor
Both of those links explain how to create a launcher icon for your program.
The following link will explain how to set the icon on the menu bar (title bar) in your program.
PyQt4 set windows taskbar icon
I hope this helps you out!

I study PyQt5 from author who give this question,also I have this problem that my icons can't show,I try some ways to catch it,that's what I do,hope it works!
First, it's important that you should use absolute path of the icons,for example:
self.setWindowIcon(QIcon("F:/Workspace/PyQT5-Study/images/web.png"))
but this not a good idea,so you can use second way like this:
from PyQt5.QtCore import QFileInfo
# ...
def initUI(self):
# ...
root = QFileInfo(__file__).absolutePath()
self.setWindowIcon(QIcon(root+'/images/web.png'))
# or
# import os
# current_dir = os.path.dirname(os.path.realpath(__file__))
# self.setWindowIcon(QIcon(os.path.join(current_dir, 'images/web.png')))
# ...
Last, if your icons also can't show, you should check this icon, if it's a legal icon.
In short, the normal images are unlimited so more, they can store many images and transform easily, but the icons have sure size,color kind,and more important,the icons have transparency, that means you can see the background, they have frame(not always straight). So you can use the web online tools to transform your image and try again,that really help me!
Also you should check the icon's source format, ensure you never change it, like .jpg to .png,and other. This will produce problem!
Wish you can solve the problem!

On windows be sure to use a real .ico file and a full path
iconpath = os.path.join(os.getcwd(),'qtlearning','assets','python.ico')
self.setWindowIcon(QIcon(iconpath))

I faced the exact same problem.
First things first. There is no setWindowIcon() method under QWidget or QMainWindow classes, in fact. you should be trying to set the QIcon at the Application level as follows.
app = QApplication(sys.argv)
app.setWindowIcon(QtGui.QIcon('home.png'))
Second, the icon thus created using this code does not reflect on the title of the window, instead it will reflect as an application icon as shown in the image below. the home.png
" icon for Application" in Ubuntu and not the " icon over the Window Title"
Finally, the path does not really matter, it can be an absolute path or a relative path, the system will consider either.

i just provided the full path of icon as simple as that

PyQt5 app exits on error where PyQt4 app would not

I have been developing a scientific application using PyQt4 for a couple of weeks, and decided to switch over to PyQt5. Aside from a few things to iron out one thing is puzzling me, and I'm not sure if its intended behavior or not.
When Using PyQt4:
if I had a python error (AttributeError, FileNotFoundError or whatever) the error message would print out to the python console, but I could continue using the PyQt4 gui application
When Using PyQt5, when I have a python error, the entire app closes on me. Is this a setting, or is this intended behavior? This is potentially disastrous as before if there was a bug, I could save the data I had acquired, but now the application will just close without warning.
Here is an example that demonstrates the behavior. This script opens a widget with a button that activates a file dialog. If a valid file is selected, the code will print the filepointer object to the command line. If no file is selected because the user hits cancel, then that case is not handled and python tries to open a file with path ''. In this both PyQt4 and PyQt5 versions throw the same python error:
FileNotFoundError: [Errno 2] No such file or directory: ''
However, the PyQt4 version will leave the widget open and the user can continue, whereas the PyQt5 version closes, with exit code of 1.
Here is the example code, executed by: "python script.py"
import sys
# from PyQt4 import QtGui as qt
# from PyQt4.QtCore import PYQT_VERSION_STR
from PyQt5 import QtWidgets as qt
from PyQt5.QtCore import PYQT_VERSION_STR
def open_a_file():
fname = qt.QFileDialog.getOpenFileName()
if PYQT_VERSION_STR[0] == '4':
f = open(fname, 'r')
print(f)
else:
f = open(fname[0], 'r')
print(f)
f.close()
if __name__ == '__main__':
app = qt.QApplication(sys.argv)
w = qt.QWidget()
w.resize(250, 150)
w.move(300, 300)
w.setWindowTitle('PyQt 4 v 5')
btn = qt.QPushButton("Open a file", w)
btn.clicked.connect(open_a_file)
w.show()
sys.exit(app.exec_())
Can I use PyQt5, but have it not crash the way that the PyQt4 version does?
Here is my current system information system information:
Windows 7 64-bit
Anaconda, Python 3.5
PyQt4 --> from conda sources
PyQt5 --> using:
conda install --channel https://conda.anaconda.org/m-labs qt5
conda install --channel https://conda.anaconda.org/m-labs pyqt5
both PyQt4 and PyQt5 are installed side by side

The old behavior can be forced by calling this code, which I found after more searching. I'm not sure I understand why this is bad behavior that needed to be deprecated, but this does work.
I submit that this should not be the default behavior, and that properly catching exceptions is the correct way to program, but given the specific purpose of my programming, and my time constraints, I find it useful to have access to as an optional mode, as I can still see the python exception traces printed to the console, and won't lose any unsaved data because of an uncaught exception.
import sys
def my_excepthook(type, value, tback):
# log the exception here
# then call the default handler
sys.__excepthook__(type, value, tback)
sys.excepthook = my_excepthook

How to embed some application window in my application using any Python GUI framework

I want some application to look like widget inside my Python application.
That's all. I dont need any interaction between them. I'm interested in solutions in any GUI toolkit for both windows and x windows.
It would be nice to have a solution with Tkinter but it's not crucial.

Using GTK on X windows (i.e. Linux, FreeBSD, Solaris), you can use the XEMBED protocol to embed widgets using gtk.Socket. Unfortunately, the application that you're launching has to explicitly support it so that you can tell it to embed itself. Some applications don't support this. Notably, I can't find a way to do it with Firefox.
Nonetheless, here's a sample program that will run either an X terminal or an Emacs session inside a GTK window:
import os
import gtk
from gtk import Socket, Button, Window, VBox, HBox
w = Window()
e = Button("Emacs")
x = Button("XTerm")
s = Socket()
v = VBox()
h = HBox()
w.add(v)
v.add(s)
h.add(e)
h.add(x)
v.pack_start(h, expand=False)
def runemacs(btn):
x.set_sensitive(False); e.set_sensitive(False)
os.spawnlp(os.P_NOWAIT, "emacs",
"emacs", "--parent-id", str(s.get_id()))
def runxterm(btn):
x.set_sensitive(False); e.set_sensitive(False)
os.spawnlp(os.P_NOWAIT, "xterm",
"xterm", "-into", str(s.get_id()))
e.connect('clicked', runemacs)
x.connect('clicked', runxterm)
w.show_all()
gtk.main()

Not enough reputation to comment on Glyphs answer. To make xterm work, in addition to the comments above one needs to also add
XTerm*allowSendEvents: True
to ~/.Xresources. (and perhaps reload those, with xrdb -load ~/.Xresources)