Designer Generated header invoking default ctor

Perdrix

I've got a class called ImageViewer that sub-classes QWidget.

I've promoted a QWidget to an ImageViewer.

The code generated looks like:

        tabWidget = new QTabWidget(DeepSkyStackerLive);
        tabWidget->setObjectName("tabWidget");
        tabWidget->setMinimumSize(QSize(730, 598));
        tabWidget->setMaximumSize(QSize(16777215, 16777215));
        stackedImage = new ImageViewer();
        stackedImage->setObjectName("stackedImage");

I expected to see

stackedImage = new ImageViewer(DeepSkyStackerLive);

What have I failed to do?

JonB

@Perdrix
Let's just start with: whatever DeepSkyStackerLive is, it appears you have laid the QTabWidget on it as a child. Have you done the same for ImageViewer, do they both show in the same place with the same parent in the hierarchy?

Also just check that the generated code does not have setParent() explicitly somewhere? Or even if stackedImage gets added to a layout?

If you run the program, at runtime what does stackedImage->parent() actually report?

Perdrix

@JonB Code won't even compile because the only ctor for ImageViewer is:

ImageViewer(QWidget* parent);

The ui file starts like this:

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>DeepSkyStackerLive</class>
 <widget class="QWidget" name="DeepSkyStackerLive">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>816</width>
    <height>748</height>
   </rect>
  </property>
  <property name="minimumSize">
   <size>
    <width>757</width>
    <height>748</height>
   </size>
  </property>
  <property name="windowTitle">
   <string>Form</string>
  </property>
  <layout class="QVBoxLayout" name="verticalLayout_4">
   <item>
    <widget class="QWidget" name="widget_2" native="true">
     <property name="maximumSize">
      <size>
       <width>16777215</width>
       <height>126</height>
      </size>
     </property>
     <property name="styleSheet">
      <string notr="true">background: qlineargradient(spread:pad, x1:0, y1:0, x2:1, y2:0, stop:0 rgba(138, 185, 242, 0), stop:1 rgba(138, 185, 242, 255))</string>
     </property>
     <layout class="QVBoxLayout" name="verticalLayout_2">
      <item>
       <layout class="QHBoxLayout" name="horizontalLayout">
        <item>
         <widget class="QLabel" name="monitorText">
          <property name="sizePolicy">
           <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
            <horstretch>0</horstretch>
            <verstretch>0</verstretch>
           </sizepolicy>
          </property>
          <property name="styleSheet">
           <string notr="true">background: qcolor(rgba(0,0,0,0))</string>
          </property>
          <property name="text">
           <string comment="IDC_MONITORINGRECT">Monitoring</string>
          </property>
         </widget>
        </item>
        <item>
         <widget class="QLabel" name="folderName">
          <property name="styleSheet">
           <string notr="true">background: qcolor(rgba(0,0,0,0))</string>
          </property>
          <property name="text">
           <string comment="IDC_MONITOREDFOLDER"><Click here to select the Monitored Folder></string>
          </property>
         </widget>
        </item>
        <item>
         <spacer name="horizontalSpacer_2">
          <property name="orientation">
           <enum>Qt::Horizontal</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
            <width>40</width>
            <height>20</height>
           </size>
          </property>
         </spacer>
        </item>
       </layout>
      </item>
      <item>
       <layout class="QHBoxLayout" name="horizontalLayout_3">
        <item>
         <widget class="QToolBar" name="toolbar">
          <property name="sizePolicy">
           <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
            <horstretch>0</horstretch>
            <verstretch>0</verstretch>
           </sizepolicy>
          </property>
          <property name="minimumSize">
           <size>
            <width>0</width>
            <height>0</height>
           </size>
          </property>
          <property name="styleSheet">
           <string notr="true">background: qcolor(rgba(0,0,0,0))</string>
          </property>
          <property name="movable">
           <bool>false</bool>
          </property>
          <property name="iconSize">
           <size>
            <width>48</width>
            <height>48</height>
           </size>
          </property>
          <property name="toolButtonStyle">
           <enum>Qt::ToolButtonTextUnderIcon</enum>
          </property>
          <property name="floatable">
           <bool>false</bool>
          </property>
          <addaction name="actionMonitor"/>
          <addaction name="actionStack"/>
          <addaction name="actionStop"/>
         </widget>
        </item>
        <item>
         <layout class="QVBoxLayout" name="verticalLayout">
          <item>
           <spacer name="verticalSpacer_1">
            <property name="orientation">
             <enum>Qt::Vertical</enum>
            </property>
            <property name="sizeType">
             <enum>QSizePolicy::Fixed</enum>
            </property>
            <property name="sizeHint" stdset="0">
             <size>
              <width>20</width>
              <height>13</height>
             </size>
            </property>
           </spacer>
          </item>
          <item>
           <widget class="QProgressBar" name="progressBar">
            <property name="value">
             <number>24</number>
            </property>
           </widget>
          </item>
          <item>
           <widget class="QLabel" name="status">
            <property name="sizePolicy">
             <sizepolicy hsizetype="Expanding" vsizetype="Preferred">
              <horstretch>0</horstretch>
              <verstretch>0</verstretch>
             </sizepolicy>
            </property>
            <property name="text">
             <string comment="IDC_STATS">Pending: %ld - Registered: %ld - Stacked: %ld - Total exposure time: %s</string>
            </property>
           </widget>
          </item>
         </layout>
        </item>
       </layout>
      </item>
     </layout>
    </widget>
   </item>
   <item>
    <widget class="QTabWidget" name="tabWidget">
     <property name="minimumSize">
      <size>
       <width>730</width>
       <height>598</height>
      </size>
     </property>
     <property name="maximumSize">
      <size>
       <width>16777215</width>
       <height>16777215</height>
      </size>
     </property>
     <property name="currentIndex">
      <number>1</number>
     </property>
     <widget class="ImageViewer" name="stackedImage">
      <property name="sizePolicy">
       <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
        <horstretch>0</horstretch>
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
      <attribute name="title">
       <string comment="IDC_STACKEDIMAGE">Stacked Image</string>
      </attribute>
     </widget>

All the controls are created as children of DeepSkyStackerLive except for stackedImage and lastImage which the ui header file tries to create using a default ctor.

JonB

@Perdrix
I have never used promotion. I would have expected the generated file would have as constructor signature ImageViewer(QWidget* parent = nullptr).

So far as I can see from your .ui, your ImageViewer is actually placed on/a child of the QTabWidget, not the DeepSkyStackerLive. Plus I thought QTabWidget would have its "pages" as some kind of <item>, but I'm not sure.

Make of it as you will. I would probably re-start with just the promoted widget on a plain, simple UI, eliminate the QTabWidget and anything else while you just get it going/reproduce a problem.

Perdrix

@JonB I have another ui that is very similar, but doesn't use a tab widget. That one works just fine.

The problem appears to be that the QWidgets that make up each tab are constructed in the ui_classname.h file using a default ctor which sort of feels "Wrong".

I think the assumption is that as QTabWidget::addTab will reparent the control it's OK to use a default ctor!

I'll add a default ctor to my class

SimonSchroeder

@Perdrix said in Designer Generated header invoking default ctor:

I think the assumption is that as QTabWidget::addTab will reparent the control it's OK to use a default ctor!

Layouts will reparent its items to the layout's widget. This works at least if the layout is first created and assigned to a widget and then addWidget(...) is called. addWidget will reparent the widget. Not sure if this also works if you first add widgets to a layout and then assign the layout to a widget. If I write this kind of code by hand (instead of using the designer) I purposefully leave out the parent when I create widgets because it is not necessary (and more to type...).