[Qt-interest] Catch QTabPane change event before change

[slayer81 at gmx.de]

Hello!

I tried to install an event filter with QObject::installEventFilter(...) which listens to visibility
changes of the QWidget lying on the QTabPane, but when I try to discard the QEvent::Hide,
it has already changed the visibility.

Your suggestion is what I should do. Unfortunately, as soon as I subclass QWidget, I
lose Qt Designer support.

Isnt there a way to prevent pane changes, maybe by fetching the click event on the pane bar
of the QTabPane?

Cheers,
Paule


Am 05.10.2010 10:53:35, schrieb David Boosalis <david.boosalis at gmail.com>:

>
>
>  Datum:  Tue, 5 Oct 2010 01:53:35 -0700
>
>  Betreff:Re: [Qt-interest] Catch QTabPane change event before change
>  Von:    David Boosalis <david.boosalis at gmail.com>
>  An:     Matthias Paul <slayer81 at gmx.de>
>  Kopie   QtInterest <qt-interest at trolltech.com>
>  (Cc):
>
>
>
>  if you subclass the widgets that go into the tab widget you can capture the
>  QWidget::showEvent(QShowEvent *)
>  before the tabChange signal gets called.  Example follows:
>
>
>
>  MyLabel::MyLabel(QString name, QWidget *parent):QLabel(name,parent)
>  {
>
>  }
>
>  void MyLabel::showEvent(QShowEvent *se)
>  {
>      qDebug() << "Show Me " << QLabel::text();
>      QLabel::showEvent(se);
>  }
>
>  TabChangeExample::TabChangeExample(QWidget *parent)
>      : QWidget(parent)
>  {
>      tabW = new QTabWidget(this);
>     
>  connect(tabW,SIGNAL(currentChanged(int)),this,SLOT(tabChangedSlot(int)));
>      myLabel1 = new MyLabel("ONE",tabW);
>      myLabel2 = new MyLabel("Two",tabW);
>      tabW->insertTab(0,myLabel1,"Alpha");
>      tabW->insertTab(2,myLabel2,"Beta");
>      QHBoxLayout *hbox = new QHBoxLayout(this);
>      setLayout(hbox);
>      hbox->addWidget(tabW);
>  }
>
>  TabChangeExample::~TabChangeExample()
>  {
>
>  }
>  void TabChangeExample::tabChangedSlot(int i)
>  {
>      qDebug() << "Tab Changed:" << i;
>  }
>
>
>
>  When I run this code, the output is as follows:
>  Show Me  "ONE"
>  Tab Changed: 0.
>
>  in the showEvent() you could probable do things to change before you show
>  it, or in this case before QLabel::showEvent() gets called.
>
>
>
>   
>
>
>  On Mon, Oct 4, 2010 at 11:37 PM, Matthias Paul <slayer81 at gmx.de> wrote:
>   Hello!
>
>   I use a QTabPane with three 3 panes. Each panel has some QTextFields for
>   user inputs.
>   If the user changes input on pane 1 and then tries to switch to pane 2 or
>   3, I'd like to display a message that asks the user whether he wants to
>   save his input or not.
>
>   There's a signal "currentChange(int)" in QTabPane, which triggers after the
>   tab has actually changed. Is there a way to catch a signal _before_ the
>   change is going to happen, so I am able to overrule the change?
>
>
>   Thank you,
>   Paule
>   --
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