Apply Layout to custom widget plugin container

[Alex87]

Hello,

I am trying to create a custom wigdet and provide it to qtcreator as a plugin. The widget is meant to be a frame, containing an icon and a title and should work as a container for other widgets. I created the widget's class + ui (ResultFrame) and the plugin class (ResultFramePlugin) as well. Everything works great so far. However, when I drag and drop the ResultFrame widget in a new project I cannot apply a layout to it. I can drag and drop other widgets to my ResultFrame widget. But the buttons for applying a layout stay disabled (see screenshot).

So my question is: Is it possible to create a custom container plugin and apply a layout in another project after dragging and dropping the plugin widget to the ui? If so, what am I supposed to do, since just returning true for isContainer() seems not to work. Maybe I must implement a sizeHint for the ResultFrame widget or something like that? I dont have any good idea what I should try and I dont know, how to figure out what I am doing wrong. So I would be thankful, if anyone can give me a hint!


Layout.PNG

Here are some code snippets of the plugin class. If I left out any important information, please let me know.

QWidget *ResultFramePlugin::createWidget(QWidget *parent)
{
    return new ResultFrame(parent);
}
 
bool ResultFramePlugin::isContainer() const
{
    return true;
}
 
QString ResultFramePlugin::domXml() const
{
    return "<widget class=\"ResultFrame\" name=\"ResultFrame\">\n"
            " <property name=\"geometry\">\n"
            "  <rect>\n"
            "   <x>0</x>\n"
            "   <y>0</y>\n"
            "   <width>50</width>\n"
            "   <height>50</height>\n"
            "  </rect>\n"
            " </property>\n"
            " <property name=\"toolTip\" >\n"
            "  <string>Frame</string>\n"
            " </property>\n"
            " <property name=\"whatsThis\" >\n"
            "  <string>Frame widget</string>\n"
            " </property>\n"
            "</widget>\n";
}

QWidget *ResultFramePlugin::createWidget(QWidget *parent)
{
    return new ResultFrame(parent);
}

bool ResultFramePlugin::isContainer() const
{
    return true;
}

QString ResultFramePlugin::domXml() const
{
    return "<widget class=\"ResultFrame\" name=\"ResultFrame\">\n"
            " <property name=\"geometry\">\n"
            "  <rect>\n"
            "   <x>0</x>\n"
            "   <y>0</y>\n"
            "   <width>50</width>\n"
            "   <height>50</height>\n"
            "  </rect>\n"
            " </property>\n"
            " <property name=\"toolTip\" >\n"
            "  <string>Frame</string>\n"
            " </property>\n"
            " <property name=\"whatsThis\" >\n"
            "  <string>Frame widget</string>\n"
            " </property>\n"
            "</widget>\n";
}

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Thanks for any help,
Alex

Edit: Maybe I should mention the Qt version: I am using Qt5.3.1 and qtcreator 3.2.81.

[anda_skoa]

Hmm, looks right. Is the isContainer() method called?

Cheers,
_

[Alex87]

Hello anda_skoa,

thank you for your quick reply!

I implemented a QMessageBox inside the isContainer() method, which shows up when I open the ui-designer for the first time. So the method is called. Any other ideas, why it does not work as expected?

Thanks for your help in advance!

[anda_skoa]

My guess would be a bug in designer.

Cheers,
_

[Alex87]

Thank you for the input. I tried the plugin in qt-creator 3.0.1 and Qt 5.2.1, but the problem still remains . If anyone has build a container plugin, which accepts a layout, I woud be glad to know how it works.

[anda_skoa]

As a work around maybe using QDesignerContainerExtension? http://qt-project.org/doc/qt-5/qdesi...extension.html

In any case it would be helpful to check the issue tracking system if the problem has been reported and report it if not.

Cheers,
_

[Alex87]

I tried QDesignerContainerExtension and it works well! Thank you for pointing me in the right direction! I read http://comments.gmane.org/gmane.comp....general/35506 and it is stated, that isContainer() only works for widget, which do not include any chidren. The suggested work around is the correct way to get a layout applied.

[anda_skoa]

Well, the last posting in the thread suggests that it should have worked for your frame

For a simple container like QFrame that does not have internal children, it
should be sufficient to return 'true' from
bool QDesignerCustomWidgetInterface::isContainer (). The user drops child
widgets directly onto those.

Cheers,
_