捕获 QApplication 中引发的异常

2022-01-12 00:00:00 python pyqt pyqt5 exception

问题描述

我正在尝试使用 PyQt5 编写一个在系统托盘中运行的应用程序.代码有时会引发异常，我需要能够捕获它们.

I'm trying to write an app that works in system tray using PyQt5. The code is sometimes raising exceptions, and I need to be able to catch them.

我希望当应用程序中发生异常时，主事件循环会退出，所以像这样捕获它应该可以工作:

I would expect that when an exception occurs in an app, the main event loop is exited, so catching it like that should work:

try:
    application.exec()
except:
    do_stuff()

在下面的例子中，当我按下Raise"按钮时，我只看到回溯，但我从来没有看到 error catched! 打印出来.

In the following example, when I press the "Raise" button, I only see the traceback, but I never see the error catched! printed.

from PyQt5 import QtWidgets, QtGui, QtCore

class ErrorApp():
    def __init__(self):
        # Init QApplication, QWidet and QMenu
        self.app = QtWidgets.QApplication([])
        self.widget = QtWidgets.QWidget()
        self.menu = QtWidgets.QMenu("menu", self.widget)

        # Add items to menu
        self.menu_action_raise = self.menu.addAction("Raise")
        self.menu_action_raise.triggered.connect(self.raise_error)

        self.menu_action_exit = self.menu.addAction("Exit")
        self.menu_action_exit.triggered.connect(self.app.exit)

        # Create the tray app
        self.tray = QtWidgets.QSystemTrayIcon(QtGui.QIcon("logo.png"), self.widget)
        self.tray.setContextMenu(self.menu)

        # Show app
        self.tray.show()

    def raise_error(self):
        assert False

e = ErrorApp()

try:
    e.app.exec()

except:
    print("error catched!")

有 2 个类似的问题，但那里的答案没有做我需要做的事情:

There are 2 similar questions, but the answers there don't do what I need to do:

抓取 PyQt 中的任何异常:OP 想要监控 异常，偶数循环不退出防止 PyQt 静默插槽中发生的异常:装饰器回答根本行不通；将 sys.exit(1) 添加到 sys.excepthook 只会关闭整个程序，而不会打印 error catched!

Grab any exception in PyQt: the OP wants to monitor the exceptions, the even loop isn't exited Preventing PyQt to silence exceptions occurring in slots: the decorator answer simply doesn't work; adding sys.exit(1) to sys.excepthook just closes the whole program, without printing error catched!

解决方案

你必须使用异常，如果你想要事件循环结束，那么你必须调用 quit()(或 exit()) 方法.

You must use the exception and, if you want the event loop to end then you must call the quit()(or exit()) method.

import sys
import traceback
from PyQt5 import QtWidgets, QtGui, QtCore


class ErrorApp:
    # ...

    def raise_error(self):
        assert False


def excepthook(exc_type, exc_value, exc_tb):
    tb = "".join(traceback.format_exception(exc_type, exc_value, exc_tb))
    print("error catched!:")
    print("error message:
", tb)
    QtWidgets.QApplication.quit()
    # or QtWidgets.QApplication.exit(0)


sys.excepthook = excepthook
e = ErrorApp()
ret = e.app.exec_()
print("event loop exited")
sys.exit(ret)

输出:

error catched!:
error message:
 Traceback (most recent call last):
  File "main.py", line 28, in raise_error
    assert False
AssertionError

event loop exited

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