QFocusData Class Reference

The QFocusData class maintains the list of widgets in the focus chain. More...

#include <qfocusdata.h>

Public Members

QWidget * focusWidget () const
QWidget * home ()
QWidget * next ()
QWidget * prev ()
QWidget * first () const
QWidget * last () const
int count () const

Detailed Description

The QFocusData class maintains the list of widgets in the focus chain.

This read-only list always contains at least one widget (i.e. the top-level widget). It provides a simple cursor which can be reset to the current focus widget using home(), or moved to its neighboring widgets using next() and prev(). You can also retrieve the count() of the number of widgets in the list. The list is a loop, so if you keep iterating, for example using next(), you will never come to the end.

Some widgets in the list may not accept focus. Widgets are added to the list as necessary, but not removed from it. This lets widgets change focus policy dynamically without disrupting the focus chain the user experiences. When a widget disables and re-enables tab focus, its position in the focus chain does not change.

When reimplementing QWidget::focusNextPrevChild() to provide special focus flow, you will usually call QWidget::focusData() to retrieve the focus data stored at the top-level widget. A top-level widget's focus data contains the focus list for its hierarchy of widgets.

The cursor may change at any time.

This class is not thread-safe.

Member Function Documentation

int QFocusData::count () const

Returns the number of widgets in the focus chain.

QWidget * QFocusData::first () const

Returns the first widget in the focus chain. The cursor is not modified.

QWidget * QFocusData::focusWidget () const

Returns the widgets in the hierarchy that are in the focus chain.

QWidget * QFocusData::home ()

Moves the cursor to the focusWidget() and returns that widget. You must call this before next() or prev() to iterate meaningfully.

QWidget * QFocusData::last () const

Returns the last widget in the focus chain. The cursor is not modified.

QWidget * QFocusData::next ()

Moves the cursor to the next widget in the focus chain. There is always a next widget because the list is a loop.

QWidget * QFocusData::prev ()

Moves the cursor to the previous widget in the focus chain. There is always a previous widget because the list is a loop.

Trademarks

Qt 3.3.8