Question

在Qt Designer 5.9中，verticalLayout中的test.ui距窗口边缘有一定距离，但是在test.ui中将PyQt 5.11.3加载到main.py后， verticalLayout延伸到窗口的边缘。

main.py ：

    #!/usr/bin/python3
import sys
from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.uic import loadUi

class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super().__init__()
        loadUi("test.ui", self)

def main():
    app = QApplication(sys.argv)
    main_window = MainWindow(app)
    main_window.show()
    sys.exit(app.exec_())


if __name__ == "__main__":
main()

test.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>350</width>
    <height>257</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Test</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <layout class="QGridLayout" name="gridLayout_2">
    <item row="0" column="0">
     <layout class="QVBoxLayout" name="verticalLayout">
      <property name="leftMargin">
       <number>0</number>
      </property>
      <property name="topMargin">
       <number>0</number>
      </property>
      <item>
       <spacer name="verticalSpacer_2">
        <property name="orientation">
         <enum>Qt::Vertical</enum>
        </property>
        <property name="sizeHint" stdset="0">
         <size>
          <width>20</width>
          <height>40</height>
         </size>
        </property>
       </spacer>
      </item>
      <item>
       <widget class="QGroupBox" name="groupBox">
        <layout class="QGridLayout" name="gridLayout">
         <item row="1" column="1">
          <widget class="QSpinBox" name="spinBox">
           <property name="maximum">
            <number>100000</number>
           </property>
           <property name="value">
            <number>1000</number>
           </property>
          </widget>
         </item>
         <item row="1" column="0">
          <widget class="QLabel" name="label_2">
           <property name="text">
            <string>Test</string>
           </property>
           <property name="alignment">
            <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>
           </property>
          </widget>
         </item>
         <item row="0" column="1">
          <widget class="QComboBox" name="comboBox">
           <property name="currentText">
            <string/>
           </property>
          </widget>
         </item>
         <item row="0" column="0">
          <widget class="QLabel" name="label1">
           <property name="text">
            <string>Test</string>
           </property>
           <property name="alignment">
            <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>
           </property>
          </widget>
         </item>
        </layout>
       </widget>
      </item>
      <item>
       <spacer name="verticalSpacer">
        <property name="orientation">
         <enum>Qt::Vertical</enum>
        </property>
        <property name="sizeHint" stdset="0">
         <size>
          <width>20</width>
          <height>40</height>
         </size>
        </property>
       </spacer>
      </item>
      <item>
       <widget class="QPushButton" name="pushButton">
        <property name="layoutDirection">
         <enum>Qt::LeftToRight</enum>
        </property>
        <property name="text">
         <string>Test</string>
        </property>
       </widget>
      </item>
     </layout>
    </item>
   </layout>
  </widget>
  <widget class="QMenuBar" name="menubar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>350</width>
     <height>28</height>
    </rect>
   </property>
  </widget>
  <widget class="QStatusBar" name="statusbar"/>
 </widget>
 <resources/>
 <connections/>
</ui>

Qt Designer 5.9中test.ui的屏幕截图：

main.py正在加载test.ui的屏幕截图：

此行为的原因是什么？

Answer 1

基于@eyllanesc的answer，这是一个monkey patch，为我解决了此问题。

该解决方案之所以有效，是因为PyQt5内部唯一关心WidgetStack.topIsLayoutWidget属性的代码是UIParser.createLayout()方法，并且仅使用该属性来决定是否将默认边距设置为零。 >

from PyQt5.uic import uiparser

uiparser.WidgetStack.topIsLayoutWidget = lambda self: False

Answer 2

如果您检查uic.loadUi()的代码，则会发现以下代码：

uiparser.py

class UIParser(object):  
    # ...
    def createLayout(self, elem):
        # ...
        margin = -1 if self.stack.topIsLayout() else self.defaults['margin']
        margin = self.wprops.getProperty(elem, 'margin', margin)
        left = self.wprops.getProperty(elem, 'leftMargin', margin)
        top = self.wprops.getProperty(elem, 'topMargin', margin)
        right = self.wprops.getProperty(elem, 'rightMargin', margin)
        bottom = self.wprops.getProperty(elem, 'bottomMargin', margin)
        # A layout widget should, by default, have no margins.
        if self.stack.topIsLayoutWidget():
            if left < 0: left = 0
            if top < 0: top = 0
            if right < 0: right = 0
            if bottom < 0: bottom = 0

    def topIsLayoutWidget(self):
        # A plain QWidget is a layout widget unless it's parent is a
        # QMainWindow or a container widget.  Note that the corresponding uic
        # test is a little more complicated as it involves features not
        # supported by pyuic.

        if type(self[-1]) is not QtWidgets.QWidget:
            return False

        if len(self) < 2:
            return False

        parent = self[-2]

        return isinstance(parent, QtWidgets.QWidget) and type(parent) not in (
                QtWidgets.QMainWindow,
                QtWidgets.QStackedWidget,
                QtWidgets.QToolBox,
                QtWidgets.QTabWidget,
                QtWidgets.QScrollArea,
                QtWidgets.QMdiArea,
                QtWidgets.QWizard,
                QtWidgets.QDockWidget)

该问题是由topIsLayoutWidget()函数引起的，因为父级将引用用作基础的小部件，在这种情况下MainWindow符合isinstance(parent, QtWidgets.QWidget) and type (parent) not in (QtWidgets.QMainWindow, ...)，因此topIsLayoutWidget()将返回True ，因此左，上，右，下将为-1，因为那些不存在的属性将更新为0，因此将通过消除默认值（9、9、9、9）来建立对contentsMargins的应用），但对于Qt Designer，contentsMargins尚未更新，仍保持其默认值。

因此，最后是一个pyqt错误，该错误也指出了注释：

# ... Note that the corresponding uic
# test is a little more complicated as it involves features not
# supported by pyuic.*

因此，有几种解决方案：

删除：

if self.stack.topIsLayoutWidget():
    if left < 0: left = 0
    if top < 0: top = 0
    if right < 0: right = 0
    if bottom < 0: bottom = 0

使用uic.loadUiType()：

#!/usr/bin/python3
import sys
from PyQt5 import QtCore, QtWidgets, uic

Ui_Interface, _ = uic.loadUiType('test.ui')

class MainWindow(QtWidgets.QMainWindow, Ui_Interface):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setupUi(self)

def main():
    app = QtWidgets.QApplication(sys.argv)
    main_window = MainWindow()
    main_window.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    main()

我更喜欢第二种解决方案，因为不应修改源代码。

Qt Designer和PyQt程序中verticalLayout的大小不同

2 个答案: