PyCharm / PyQt：如何使用动态加载的 ui 文件获取代码完成

Question

假设我在 Qt Designer 中创建了一个 ui 文件，我想动态加载它然后操作小部件，例如：

例子.py：

from PyQt5 import QtWidgets, uic

class MyWidget(QtWidgets.QWidget):

    def __init__(self, parent=None):
        super(MyWidget, self).__init__(parent)
        uic.loadUi('example.ui', self)

        # No code completion here for self.myPushButton:
        self.myPushButton.clicked.connect(self.handleButtonClick)

        self.show()

在 PyCharm (2017.1.4) 中，是否有标准/方便的方式为以这种方式加载的小部件启用代码完成？

目前我正在使用这个（在加载 ui 文件后在构造函数中编写）：

self.myPushButton = self.myPushButton  # type: QtWidgets.QPushButton
# Code completion for myPushButton works at this point

我也想到了这一点，但它似乎并没有做到这一点：

assert isinstance(self.myPushButton, QtWidgets.QPushButton)
# PyCharm does not even recognise myPushButton as an attribute of self at this point

最后，我也想到了使用python stubs，比如：

例子.pyi：

class MyWidget(QtWidgets.QWidget):

    def __init__(self):
        self.myPushButton: QtWidgets.QPushButton = ... 

但是，在 example.py 之外的代码中正确识别了 myPushButton，但在 example.py 本身内部的代码中无法正确识别，这与我想要的相反。

我也在考虑采用我的第一种方法，但所有这些行都放在一个永远不会被调用的私有方法中，例如：

例子.py：

from PyQt5 import QtWidgets, uic

class MyWidget(QtWidgets.QWidget):

    def __init__(self, parent=None):
        super(MyWidget, self).__init__(parent)
        uic.loadUi('example.ui', self)

        # Code completion now works here for self.myPushButton:
        self.myPushButton.clicked.connect(self.handleButtonClick)

        self.show()

    def __my_private_method_never_called():
        self.myPushButton = self.myPushButton  # type: QtWidgets.QPushButton

        # Or even this (it should have the same effect if this
        # function is never called, plus it is less verbose):
        self.myPushButton = QtWidgets.QPushButton()

        # If I want to make sure that this is never called
        # could raise an error at some point:
        raise YouShouldNotHaveCalledThisError()

这似乎工作正常，它还允许我将所有类型提示代码组合在一起，与其余代码隔离。我什至可以通过解析 ui 文件来制作一些脚本来为我编写所有这些行。我只是想知道阅读我的代码的人是否会发现这种方法非常非正统，即使我清楚地评论了为什么我要编写技术上无用的私有函数。

Answer 1

If anybody is interested, I made the script I mentioned to parse the .ui files and generate stub code ready to be copied to my class:

ui_stub_generator.py:

from __future__ import print_function

import os
import sys
import xml.etree.ElementTree


def generate_stubs(file):
    root = xml.etree.ElementTree.parse(file).getroot()
    print('Stub for file: ' + os.path.basename(file))
    print()
    print('    def __stubs(self):')
    print('        """ This just enables code completion. It should never be called """')

    for widget in root.findall('.//widget'):
        name = widget.get('name')
        if len(name) > 3 and name[:2] == 'ui' and name[2].isupper():
            cls = widget.get('class')
            print('        self.{} = QtWidgets.{}()'.format(
                name, cls
            ))

    print('        raise AssertionError("This should never be called")')
    print()


def main():
    for file in sys.argv[1:]:
        generate_stubs(file)


if __name__ == '__main__':
    main()

This only parses widgets whose names start with 'ui' followed by an uppercase letter, such as 'uiMyWidget', which is the naming convention that I typically follow in the Qt Designer. By doing this, the widgets with names automatically generated by the Qt Designer are ignored (if I cared about these, I would have given them a proper name). It should be straightforward to update this for any other naming conventions, or other type of objects, such as actions.

For convenience, I have set this up as an external tool in PyCharm as well; see screenshot here (change the paths as appropriate). That way, I only have to right-click my ui file in the project window, then External Tools -> Stub Generator for Qt UI Files, and I get the following output in the Run window ready to be copied:

from __future__ import print_function

import os
import sys
import xml.etree.ElementTree


def generate_stubs(file):
    root = xml.etree.ElementTree.parse(file).getroot()
    print('Stub for file: ' + os.path.basename(file))
    print()
    print('    def __stubs(self):')
    print('        """ This just enables code completion. It should never be called """')

    for widget in root.findall('.//widget'):
        name = widget.get('name')
        if len(name) > 3 and name[:2] == 'ui' and name[2].isupper():
            cls = widget.get('class')
            print('        self.{} = QtWidgets.{}()'.format(
                name, cls
            ))

    print('        raise AssertionError("This should never be called")')
    print()


def main():
    for file in sys.argv[1:]:
        generate_stubs(file)


if __name__ == '__main__':
    main()