does not show icons

问题

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:

回答1:

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.

回答2:

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!

回答3:

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!

来源：https://stackoverflow.com/questions/44080247/does-not-show-icons