two different main code loaded the same .ui file and the one is working and other not, why?

Daniel Breeze

this is gonna drive me crazy.

working code is here

import sys
from PySide6 import QtCore, QtGui, QtWidgets
from PySide6.QtUiTools import QUiLoader

loader = QUiLoader()
app = QtWidgets.QApplication(sys.argv)
window = loader.load("mainwindow.ui", None)
window.show()
sys.exit(app.exec())

not working is here, and this code form official webside link text

import sys
from PySide6.QtUiTools import QUiLoader
from PySide6.QtWidgets import QApplication
from PySide6.QtCore import QFile, QIODevice

if __name__ == "__main__":
    app = QApplication(sys.argv)

    ui_file_name = "mainwindow.ui"
    ui_file = QFile(ui_file_name)
    if not ui_file.open(QIODevice.ReadOnly):
        print(f"Cannot open {ui_file_name}: {ui_file.errorString()}")
        sys.exit(-1)
    loader = QUiLoader()
    window = loader.load(ui_file)
    ui_file.close()
    if not window:
        print(loader.errorString())
        sys.exit(-1)
    window.show()

    sys.exit(app.exec())

here is mianwindow.ui code

<?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>959</width>
    <height>731</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <layout class="QHBoxLayout" name="horizontalLayout">
    <item>
     <widget class="QWidget" name="widgetLeft" native="true">
      <property name="minimumSize">
       <size>
        <width>350</width>
        <height>0</height>
       </size>
      </property>
      <layout class="QVBoxLayout" name="verticalLayout">
       <item>
        <widget class="QWidget" name="widget" native="true">
         <layout class="QFormLayout" name="formLayout">
          <item row="0" column="0">
           <widget class="QLabel" name="label">
            <property name="text">
             <string>温室大棚类型</string>
            </property>
           </widget>
          </item>
          <item row="0" column="1">
           <widget class="QComboBox" name="comboBox"/>
          </item>
          <item row="1" column="0">
           <widget class="QLabel" name="label_2">
            <property name="text">
             <string>风向（度）</string>
            </property>
           </widget>
          </item>
          <item row="1" column="1">
           <widget class="QComboBox" name="comboBox_2"/>
          </item>
         </layout>
        </widget>
       </item>
       <item>
        <widget class="QWidget" name="widget_2" native="true">
         <layout class="QVBoxLayout" name="verticalLayout_2">
          <item>
           <widget class="QGroupBox" name="groupBox">
            <property name="title">
             <string>尺寸</string>
            </property>
            <layout class="QFormLayout" name="formLayout_2">
             <item row="0" column="0">
              <widget class="QLabel" name="label_3">
               <property name="text">
                <string>跨度（mm）</string>
               </property>
              </widget>
             </item>
             <item row="0" column="1">
              <widget class="QComboBox" name="comboBox_3"/>
             </item>
             <item row="1" column="0">
              <widget class="QLabel" name="label_4">
               <property name="text">
                <string>脊高（mm）</string>
               </property>
              </widget>
             </item>
             <item row="1" column="1">
              <widget class="QComboBox" name="comboBox_4"/>
             </item>
             <item row="2" column="0">
              <widget class="QLabel" name="label_5">
               <property name="text">
                <string>后屋面投影（mm）</string>
               </property>
              </widget>
             </item>
             <item row="2" column="1">
              <widget class="QComboBox" name="comboBox_5"/>
             </item>
             <item row="3" column="0">
              <widget class="QLabel" name="label_6">
               <property name="text">
                <string>北墙倾角（度）</string>
               </property>
              </widget>
             </item>
             <item row="3" column="1">
              <widget class="QComboBox" name="comboBox_6"/>
             </item>
             <item row="4" column="0">
              <widget class="QLabel" name="label_7">
               <property name="text">
                <string>北墙高（mm）</string>
               </property>
              </widget>
             </item>
             <item row="4" column="1">
              <widget class="QComboBox" name="comboBox_7"/>
             </item>
            </layout>
           </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>158</height>
          </size>
         </property>
        </spacer>
       </item>
       <item>
        <widget class="QWidget" name="widget_3" native="true">
         <layout class="QHBoxLayout" name="horizontalLayout_2">
          <item>
           <widget class="QPushButton" name="pushButton_3">
            <property name="minimumSize">
             <size>
              <width>50</width>
              <height>0</height>
             </size>
            </property>
            <property name="maximumSize">
             <size>
              <width>50</width>
              <height>16777215</height>
             </size>
            </property>
            <property name="text">
             <string>查询</string>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QPushButton" name="pushButton_2">
            <property name="minimumSize">
             <size>
              <width>50</width>
              <height>0</height>
             </size>
            </property>
            <property name="maximumSize">
             <size>
              <width>50</width>
              <height>16777215</height>
             </size>
            </property>
            <property name="text">
             <string>输出</string>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QPushButton" name="pushButton">
            <property name="minimumSize">
             <size>
              <width>50</width>
              <height>0</height>
             </size>
            </property>
            <property name="maximumSize">
             <size>
              <width>50</width>
              <height>16777215</height>
             </size>
            </property>
            <property name="text">
             <string>退出</string>
            </property>
           </widget>
          </item>
         </layout>
        </widget>
       </item>
      </layout>
     </widget>
    </item>
    <item>
     <widget class="QWidget" name="widgetRight" native="true">
      <layout class="QVBoxLayout" name="verticalLayout_3">
       <item>
        <widget class="QWidget" name="widget_4" native="true">
         <property name="minimumSize">
          <size>
           <width>400</width>
           <height>400</height>
          </size>
         </property>
         <layout class="QHBoxLayout" name="horizontalLayout_3">
          <item>
           <widget class="QWidget" name="widget_5" native="true">
            <property name="minimumSize">
             <size>
              <width>400</width>
              <height>400</height>
             </size>
            </property>
           </widget>
          </item>
          <item>
           <spacer name="horizontalSpacer">
            <property name="orientation">
             <enum>Qt::Horizontal</enum>
            </property>
            <property name="sizeHint" stdset="0">
             <size>
              <width>0</width>
              <height>20</height>
             </size>
            </property>
           </spacer>
          </item>
         </layout>
        </widget>
       </item>
       <item>
        <widget class="QColumnView" name="columnView"/>
       </item>
      </layout>
     </widget>
    </item>
   </layout>
  </widget>
  <widget class="QMenuBar" name="menubar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>959</width>
     <height>22</height>
    </rect>
   </property>
   <widget class="QMenu" name="menu">
    <property name="title">
     <string>文件</string>
    </property>
    <addaction name="actionasd"/>
    <addaction name="action123"/>
   </widget>
   <addaction name="menu"/>
  </widget>
  <widget class="QStatusBar" name="statusbar"/>
  <action name="actionasd">
   <property name="text">
    <string>打开图片</string>
   </property>
  </action>
  <action name="action123">
   <property name="text">
    <string>退出</string>
   </property>
  </action>
 </widget>
 <resources/>
 <connections/>
</ui>

SGaist

Hi and welcome to devnet,

Which version of PySide6 ?
On which platform ?

JonB

@Daniel-Breeze said in two different main code loaded the same .ui file and the one is working and other not, why?:

not working is here,

In what way "not working"? Did you step through it to make sure where it got to?

Daniel Breeze

@JonB

I change that like this

import sys

from PySide6.QtWidgets import QApplication
from PySide6.QtUiTools import QUiLoader


if __name__ == "__main__":
    app = QApplication(sys.argv)

#    ui_file_name = "mainwindow.ui"
#    ui_file = QFile(ui_file_name)
#    if not ui_file.open(QIODevice.ReadOnly):
#        print(f"Cannot open {ui_file_name}: {ui_file.errorString()}")
#        sys.exit(-1)
    print("hah")
    loader = QUiLoader()
    print("hah")
    window = loader.load("mainwindow.ui")
#    ui_file.close()
#    if not window:
#        print(loader.errorString())
#        sys.exit(-1)
    window.show()

    sys.exit(app.exec())

and I run the program with debugging, when it execute loader = QUiLoader() it stoped, and it can't execute next line. like there is one "hah" be printed

JonB

@Daniel-Breeze
Although it seems the wrong way round to me, in your "working" first code case you have the loader = QUiLoader() statement before you create the QApplication() object. Try moving your creation of QUiLoader() to come before QApplication() in the second non-working case?

Daniel Breeze

@JonB
thanks a lot, solved. but if you need create loader first, why that official example didn't, I'am really confused.

JonB

@Daniel-Breeze
I'm actually surprised that works. You would think the QApplication ought to come first, but it was the most obvious difference I could spot.

friedemannkleint

If this is 6.6; it might be a manifestation of https://bugreports.qt.io/browse/QTBUG-118317 .

Solved two different main code loaded the same .ui file and the one is working and other not, why?