Dynamically created QWidget in QFormLayout does not have frame, even if explicitly asked to do so

Question

I have a little problem with this bit of code:

DatasetWidget::DatasetWidget(QWidget *parent) : QWidget(parent),
ui(new Ui::DatasetWidget)
{
    ui->setupUi(this);

    // cut non-ui related stuff here ...

    // Add widgets
    for(int loop=0;loop<theAmountOfItemsWeAdd;++loop)
    {
        QLabel * ql=new QLabel("Caption");
        QLineEdit * qle=new QLineEdit(this);
        qle->setSizePolicy(QSizePolicy::Policy::Expanding,QSizePolicy::Policy::Fixed);
        ui->formDisp->addRow(ql,qle); // ui->formDisp is of type QFormLayout*
    }

// more non-UI related code

I'm creating a QLineEdit widget and adding it to a QFormLayout, "formDisp". For some weird reason that I can't figure out, the created QLineEdit does not have any frame and setFrame doesn't enable it.

I furthermore append the relevant parts of the .ui file here:

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>DatasetWidget</class>
 <widget class="QWidget" name="DatasetWidget">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>723</width>
    <height>591</height>
   </rect>
  </property>
  <property name="sizePolicy">
   <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
    <horstretch>0</horstretch>
    <verstretch>0</verstretch>
   </sizepolicy>
  </property>
  <property name="windowTitle">
   <string>Datensatz</string>
  </property>
  <layout class="QVBoxLayout" name="verticalLayout">
   <item>
      <widget class="QLabel" name="lblCaptionDatensatz">
       <property name="text">
        <string>Datensatz:</string>
       </property>
      </widget>
     </item>
     <item>
      <widget class="QLabel" name="lblDatensatz">
       <property name="font">
        <font>
         <weight>75</weight>
         <bold>true</bold>
         <underline>true</underline>
        </font>
       </property>
       <property name="text">
        <string>C-XXXX-XXX</string>
       </property>
      </widget>
     </item>
     <item>
      <widget class="QLineEdit" name="leDescriptor">
       <property name="sizePolicy">
        <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
         <horstretch>0</horstretch>
         <verstretch>0</verstretch>
        </sizepolicy>
       </property>
       <property name="toolTip">
        <string extracomment="ServiceTag"/>
       </property>
       <property name="maxLength">
        <number>7</number>
       </property>
      </widget>
     </item>
     <item>
      <spacer name="horizontalSpacer">
       <property name="orientation">
        <enum>Qt::Horizontal</enum>
       </property>
       <property name="sizeHint" stdset="0">
        <size>
         <width>40</width>
         <height>20</height>
        </size>
       </property>
      </spacer>
     </item>
     <item>
      <widget class="QPushButton" name="cmdDelete">
       <property name="text">
        <string/>
       </property>
       <property name="icon">
        <iconset resource="hawams.qrc">
         <normaloff>:/icons/res/trash-3x.png</normaloff>:/icons/res/trash-    3x.png</iconset>
       </property>
      </widget>
     </item>
    </layout>
   </item>
   <item>
    <layout class="QFormLayout" name="formDisp"/>
   </item>
   <item>
    <widget class="Line" name="line">
     <property name="orientation">
      <enum>Qt::Horizontal</enum>
     </property>
    </widget>
   </item>
  </layout>
 </widget>
<connections/>
</ui>

As widgets added in QtCreator look exactly how they are supposed to look, I suppose something about my code must be wrong.

Update: Problem solved: Surrounding QWidget was being used inside a QListView, where it replaced an older, fixed-size version of the widget. In the code that fills the QListView with items, there was a hard-coded size hint which forced Qt to resize the new (bigger) version of the QWidget and "squeeze" it vertically. Conclusion: When you embed a QWidget derivate in buggy old code that resizes it so there isn't enough space anymore to display all items inside the QWidget's layout, things get messy.

Please show more of your code because these 4 lines is not enough — Hermann
As I don't know which parts of the code are relevant, I appended some more context information. — user6468803
Probably a silly question but... are you absolutely sure the QLineEdit doesn't have a frame? On the system I'm sitting at the difference is barely perceptible. — G.M.
@G.M. I'm absolutely sure - the QLineEdit is on a white background (default background colour on my system for QWidgets that are inside a QListWidget, which is the case with the widget that we're talking about). It definitely doesn't have a frame. — user6468803

Kuba hasn't forgotten Monica Kuba hasn't forgotten Monica · Accepted Answer · 2016-06-15T15:29:04

The setFrame(true) is a no-op since the frame is set by default.

Alas, I can't reproduce - the following has both line edits looking identical, save for their size, and their minimum sizes are set to different values, with the second one being larger than first one. A QFormLayout does not enforce a fixed row height!

// https://github.com/KubaO/stackoverflown/tree/master/questions/lineedit-frame-37831979
#include <QtWidgets>
#include <QtUiTools>

const char ui[] = R"EOF(
  <ui version="4.0">
   <class>DatasetWidget</class>
   <widget class="QWidget" name="DatasetWidget">
    <layout class="QVBoxLayout" name="verticalLayout">
     <item>
      <widget class="QLabel" name="lblCaptionDatensatz">
       <property name="text">
        <string>Datensatz:</string>
       </property>
      </widget>
     </item>
     <item>
      <widget class="QLabel" name="lblDatensatz">
       <property name="text">
        <string>C-XXXX-XXX</string>
       </property>
      </widget>
     </item>
     <item>
      <widget class="QLineEdit" name="leDescriptor">
       <property name="maxLength">
        <number>7</number>
       </property>
      </widget>
     </item>
     <item>
      <layout class="QFormLayout" name="formDisp"></layout>
     </item>
    </layout>
   </widget>
  <connections/>
  </ui>)EOF";

int main(int argc, char ** argv) {
   QApplication app{argc, argv};
   QBuffer buf;
   buf.setData(ui, sizeof(ui));
   auto w = QUiLoader().load(&buf);
   auto & layout = *w->findChild<QFormLayout*>("formDisp");
   QLineEdit edit1, edit2;
   layout.addRow("Edit1", &edit1);
   layout.addRow("Edit2", &edit2);
   edit1.setMinimumHeight(50);
   edit2.setMinimumHeight(100);
   w->show();
   return app.exec();
}

Dynamically created QWidget in QFormLayout does not have frame, even if explicitly asked to do so

2 Answers