是否可能在QtDesigner.ui文件中找到升级小部件类的子级？

Question

在下面的代码中，我在QtDesigner中放置了一些元素，然后是两个空Qframe，分别命名为my_widget_01和my_widget_02：

我已经将它们升级为MyWidget类，它基本上只是在Python代码中添加了一个模型标签：

现在，我想做的是，以列表的形式“查找”这些自定义对象，或者按名称，或者按类；但由于某种原因我不能。正如您在下面的代码中所看到的，如果我运行self.findChildren(QtWidgets.QFrame)，它会找到一组对象，包括自定义对象-但是如果我尝试self.findChildren(MyWidget)，则返回一个空列表。另外，如果运行self.dumpObjectTree()，输出中会出现类MyWidget的对象-因此对我来说有点奇怪，为什么.findChildren找不到它们

到目前为止，我发现：

How to find an object by name in pyqt?

You can use QObject::findChild method.

因此，这篇文章指出，即使按名称（.objectName()）查找，也应该使用findChild

access element from .ui

You don't need to use findChild() since if you use loadUi or loadUiType it will map the objects using the objectName.

这是指那篇文章中的OP问题，因此我无法判断在这种情况下原则上是否可以使用findChild()或findChildren()

在任何情况下，我都不想手动保存名称列表[self.my_widget_01, self.my_widget_02]，因为除了.ui中存在的小部件之外，还可能会动态添加一些小部件-因此我非常非常非常希望按名称正则表达式（例如"my_widget_\d\d"）或按类查找它们（因此我会查找MyWidget）；在这种情况下，这并不重要，因为我会将所有MyWidget小部件命名为my_widget_XY。我需要这个，这样我就可以在它们上面循环，不管它们最终在GUI中有多少个

这（获取所有升级的MyWidget小部件的列表，不管它们是否存在于.ui文件中，或者是动态添加的）是否可以在PyQt5中执行？如果可以，如何执行

test1.ui：

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>589</width>
    <height>302</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <widget class="QSplitter" name="splitter">
    <property name="geometry">
     <rect>
      <x>30</x>
      <y>40</y>
      <width>558</width>
      <height>192</height>
     </rect>
    </property>
    <property name="orientation">
     <enum>Qt::Horizontal</enum>
    </property>
    <widget class="QListView" name="listView"/>
    <widget class="QTreeView" name="treeView"/>
    <widget class="QFrame" name="frame">
     <property name="frameShape">
      <enum>QFrame::StyledPanel</enum>
     </property>
     <property name="frameShadow">
      <enum>QFrame::Raised</enum>
     </property>
     <layout class="QHBoxLayout" name="horizontalLayout">
      <item>
       <widget class="MyWidget" name="my_widget_02">
        <property name="frameShape">
         <enum>QFrame::StyledPanel</enum>
        </property>
        <property name="frameShadow">
         <enum>QFrame::Raised</enum>
        </property>
       </widget>
      </item>
      <item>
       <widget class="MyWidget" name="my_widget_01">
        <property name="frameShape">
         <enum>QFrame::StyledPanel</enum>
        </property>
        <property name="frameShadow">
         <enum>QFrame::Raised</enum>
        </property>
       </widget>
      </item>
     </layout>
    </widget>
   </widget>
  </widget>
  <widget class="QMenuBar" name="menubar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>589</width>
     <height>21</height>
    </rect>
   </property>
  </widget>
  <widget class="QStatusBar" name="statusbar"/>
 </widget>
 <customwidgets>
  <customwidget>
   <class>MyWidget</class>
   <extends>QFrame</extends>
   <header>test1</header>
   <container>1</container>
  </customwidget>
 </customwidgets>
 <resources/>
 <connections/>
</ui>

test1.py

import sys
from PyQt5 import QtCore, QtWidgets, QtGui, uic
from PyQt5.QtCore import pyqtSlot

class MyWidget(QtWidgets.QFrame):
  def __init__(self, *args, **kwargs):
    super(MyWidget, self).__init__(*args, **kwargs)
    self.hlay = QtWidgets.QHBoxLayout(self)
    self.hlay.setContentsMargins(1, 1, 1, 1)
    self.label = QtWidgets.QLabel(text="{}".format(self))
    self.hlay.addWidget(self.label, 0, QtCore.Qt.AlignVCenter)

class MyMainWindow(QtWidgets.QMainWindow):
  def __init__(self):
    super(MyMainWindow, self).__init__()
    uic.loadUi('test1.ui', self)
    self.dumpObjectTree() # debug, auto-prints to stdout
    print("find QFrame:", self.findChildren(QtWidgets.QFrame)) # find QFrame: [<PyQt5.QtWidgets.QSplitter object at 0x00000000060f8a60>, <PyQt5.QtWidgets.QFrame object at 0x00000000060f8c10>, <test1.MyWidget object at 0x00000000060f8d30> ...
    print("find MyWidget:", self.findChildren(MyWidget)) # []
    self.show()
    print("after show")
    print("find MyWidget:", self.findChildren(MyWidget)) # []
    QtCore.QTimer.singleShot(1, self.delayed_init) # run after 1 ms

  def delayed_init(self):
    print("delayed MyWidget:", self.findChildren(MyWidget)) # []


def main():
  app = QtWidgets.QApplication(sys.argv)
  window = MyMainWindow()
  sys.exit(app.exec_())

if __name__ == "__main__":
  main()

终端中的输出：

$ python3 /tmp/test1.py
MyMainWindow::MainWindow
    QMainWindowLayout::_layout
    QWidget::centralwidget
        QSplitter::splitter
            QFrame::frame
                QHBoxLayout::horizontalLayout
                MyWidget::my_widget_02
                    QHBoxLayout::
                    QLabel::
                MyWidget::my_widget_01
                    QHBoxLayout::
                    QLabel::
            QTreeView::treeView
                QWidget::qt_scrollarea_viewport
                QWidget::qt_scrollarea_hcontainer
                    QScrollBar::
                    QBoxLayout::
                QWidget::qt_scrollarea_vcontainer
                    QScrollBar::
                    QBoxLayout::
                QStyledItemDelegate::
                QHeaderView::
                    QWidget::qt_scrollarea_viewport
                    QWidget::qt_scrollarea_hcontainer
                        QScrollBar::
                        QBoxLayout::
                    QWidget::qt_scrollarea_vcontainer
                        QScrollBar::
                        QBoxLayout::
            QListView::listView
                QWidget::qt_scrollarea_viewport
                QWidget::qt_scrollarea_hcontainer
                    QScrollBar::
                    QBoxLayout::
                QWidget::qt_scrollarea_vcontainer
                    QScrollBar::
                    QBoxLayout::
                QStyledItemDelegate::
            QSplitterHandle::qt_splithandle_
            QSplitterHandle::qt_splithandle_
            QSplitterHandle::qt_splithandle_
    QMenuBar::menubar
        QToolButton::qt_menubar_ext_button
    QStatusBar::statusbar
        QSizeGrip::
        QHBoxLayout::
            QVBoxLayout::
                QHBoxLayout::
find QFrame: [<PyQt5.QtWidgets.QSplitter object at 0x00000000060f9af0>, <PyQt5.QtWidgets.QFrame object at 0x00000000060f9ca0>, <test1.MyWidget object at 0x00000000060f9dc0>, <PyQt5.QtWidgets.QLabel object at 0x0000000006684160>, <test1.MyWidget object at 0x00000000066841f0>, <PyQt5.QtWidgets.QLabel object at 0x0000000006684310>, <PyQt5.QtWidgets.QTreeView object at 0x00000000060f9c10>, <PyQt5.QtWidgets.QHeaderView object at 0x00000000066844c0>, <PyQt5.QtWidgets.QListView object at 0x00000000060f9b80>]
find MyWidget: []
after show
find MyWidget: []
delayed MyWidget: []

Answer 1

说明：

问题在于，从main实例化的MyFrame与升级创建的MyFrame属于不同的模块，这可以通过查看过滤器的输出来观察：

find QFrame: [... , <test1.MyWidget object at 0x00000000060f9dc0>, ... , <test1.MyWidget object at 0x00000000066841f0>, ...

但是如果您运行print(MyWidget())，您会得到：

<__main__.MyWidget object at 0x7feaf056fa60>

解决方案：

除此之外，该代码还可以生成循环导入，这比提升类位于与主文件不同的模块中要好

├── mywidget.py
├── test1.py
└── test1.ui

mywidget.py

from PyQt5 import QtCore, QtWidgets


class MyWidget(QtWidgets.QFrame):
    def __init__(self, *args, **kwargs):
        super(MyWidget, self).__init__(*args, **kwargs)
        self.hlay = QtWidgets.QHBoxLayout(self)
        self.hlay.setContentsMargins(1, 1, 1, 1)
        self.label = QtWidgets.QLabel(text="{}".format(self))
        self.hlay.addWidget(self.label, 0, QtCore.Qt.AlignVCenter)

test1.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>589</width>
    <height>302</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <widget class="QSplitter" name="splitter">
    <property name="geometry">
     <rect>
      <x>30</x>
      <y>40</y>
      <width>558</width>
      <height>192</height>
     </rect>
    </property>
    <property name="orientation">
     <enum>Qt::Horizontal</enum>
    </property>
    <widget class="QListView" name="listView"/>
    <widget class="QTreeView" name="treeView"/>
    <widget class="QFrame" name="frame">
     <property name="frameShape">
      <enum>QFrame::StyledPanel</enum>
     </property>
     <property name="frameShadow">
      <enum>QFrame::Raised</enum>
     </property>
     <layout class="QHBoxLayout" name="horizontalLayout">
      <item>
       <widget class="MyWidget" name="my_widget_02">
        <property name="frameShape">
         <enum>QFrame::StyledPanel</enum>
        </property>
        <property name="frameShadow">
         <enum>QFrame::Raised</enum>
        </property>
       </widget>
      </item>
      <item>
       <widget class="MyWidget" name="my_widget_01">
        <property name="frameShape">
         <enum>QFrame::StyledPanel</enum>
        </property>
        <property name="frameShadow">
         <enum>QFrame::Raised</enum>
        </property>
       </widget>
      </item>
     </layout>
    </widget>
   </widget>
  </widget>
  <widget class="QMenuBar" name="menubar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>589</width>
     <height>26</height>
    </rect>
   </property>
  </widget>
  <widget class="QStatusBar" name="statusbar"/>
 </widget>
 <customwidgets>
  <customwidget>
   <class>MyWidget</class>
   <extends>QFrame</extends>
   <header>mywidget</header>
   <container>1</container>
  </customwidget>
 </customwidgets>
 <resources/>
 <connections/>
</ui>

test1.py

import sys
from PyQt5 import QtCore, QtWidgets, uic

from mywidget import MyWidget


class MyMainWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super(MyMainWindow, self).__init__()
        uic.loadUi("test1.ui", self)
        print("find MyWidget:", self.findChildren(MyWidget))


def main():
    app = QtWidgets.QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    sys.exit(app.exec_())


if __name__ == "__main__":
    main()

输出：

find MyWidget: [<mywidget.MyWidget object at 0x7f8d2c01e280>, <mywidget.MyWidget object at 0x7f8d2c01e430>]