QTreeView add widget below/around the widget from within QTreeView widget...

Dariusz

Hey

I have extended QTreeView and now I would like to "squeeze" the view itself and add widgets around the QTreeView "content/display" area. Its fairly important to me to keep the base class as QTreeView so all user calls are directed to the treeView and all extra "components" are a hidden part of the widget. How can I squeeze the qtreeview and then add widgets/area around the "view" ?

Initially, I was trying to use set setViewportMargins() but that did not "squeeze" the view. I'm tinkering with it, but so far no luck.

Can anyone suggest any options?

Regards
Dariusz
TIA

SGaist

Hi,

Why not implement a subclass of QWidget that will contain your QTreeView and whatever other widgets you want around ?

Dariusz

@SGaist Because then user cant do widget->setModel() without me re-implementing all needed QTreeView functions.

SGaist

You can provide that method, or you can follow the same logic as for example QComboBox uses and make some internal parts available.

Dariusz

Hmm I would prefer avoiding hand providing all methods I need to of QTreeView - like a wrapper.
Will read in to QComboBox.
So far I tried also adding a layout QTreeView which somehow worked, but the problem is that layout and its children are located over the tree view and not above/below/etc

SGaist

What design do you have in mind ?

Dariusz

To start with I was hoping to provide a "external" drop area that would drop items in specific place in view if dropped on to. Right now I've used resizeEvent to move a QLabel styled as drop area around qTreeView, but I can only move it over the treeView. I want to squeeze tree view to place the label(drop area) in different places. I also would like to tinker with other ideas but so far this is the main one.

resizeEvent()
        _dropArea->move(1, viewport()->height() + 2);
        _dropArea->setFixedWidth(width() - 2);

SGaist

Then you should really compose a new widget. Part of your description makes me think of QMainWindow's implementation with its QDockWidget areas.

Dariusz

Is there not a simple way to force redraw of widget ? Like giving it different margins/etc? I tried with geometry but thats being overridden by layout. SetViewportMargins() seems to be overwritten by scrollArea I think.

SGaist

You can re-implement QTreeView's paintEvent but still, it doesn't change the fact that you are trying to compose a complex widget within an already complex widget.

You seem to want to avoid providing a relatively simple API while at the same time trying to implement a very complex workaround. As suggested before, you can use the QComboBox model which allows to access some internal parts (for example through view while providing a simple API like setModel or setView.

Dariusz

Well its more like case study to see how far widgets can be pushed/break apart. Ill try paint event next. But never did any extensive widget editing there so should be interesting. Its kinda... common, say I want to make a set, QLineEdit+QPushButton, I would just want to expose qlineedit and q pushbutton should do all the magic atomatically the second lineEdit has been made. So I can see more and more use cases for this idea. I don't think is particularly good having to make QWidget,QLayout, QlineEdit and QPushButton if I could just make QLineEdit + QPushButton.

Also in qt examples they show also some simmilar systems where 1 widget is aided by another one but only the main widget is being exposed
http://doc.qt.io/qt-5/qtwidgets-itemviews-frozencolumn-example.html
Also in here >
http://doc.qt.io/qt-5/qtwidgets-widgets-codeeditor-example.html
Too bad that setting viewport margins in treeView like in QPlainTextEdit editor does not work :-(
Regards
Dariusz

Dariusz

Ok so after LOTS of fighting with QTreeView... I started looking at viewport() and wuaila!

void myTree::resizeEvent(QResizeEvent *event) {
    QAbstractItemView::resizeEvent(event);
    b->setFixedSize(event->size().width(), 25);
    b->move(0,height()-25);
    viewport()->setMaximumHeight(height() - 50);
};

Now my viewport gets painted exactly where I want it to, and the extra buttons can be placed in area where I want it to (b is the button) + its all nice all in one widget. I can expose needed controls for b as pert spec but drawing is as it should. Yay!