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.
See also QWidget::focusNextPrevChild(), QWidget::setTabOrder(), QWidget::focusPolicy, and Miscellaneous Classes.
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.
This file is part of the Qt toolkit.
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