Animation of list items/redrawing Qt QListView - c++

Question

What I'd like to achieve:
A visual indication to draw attention to newly added items in a QListView. I had in mind having the background color 'throb' once (fading from a color to the background).
The setup
I have a model/view using QListView displaying QStandardItems. Qt version 4.7
What I've tried:
I've created a new class derived from QStyledItemDelegate. I have my own paint method to render the item. That part works. I created a QTimeLine object and set it up to create events to redraw the items.
I can't figure out how to trigger redraws of the QListView item.
In the item delegate constructor:
timeLine = new QTimeLine( 3000, this );
timeLine->setFrameRange( 100, 0 );
connect( timeLine, SIGNAL( frameChanged( int ) ), this, SLOT( update() ) );
timeLine->start();
I tried connecting to the sizehintChanged event but this does not work
void myDelegate::update()
{
const QModelIndex index;
emit QStyledItemDelegate::sizeHintChanged( index );
}
Any suggestions? Can this be done with style sheets?

Answer 1

The standard practice to include animations into code is to use state machines.
Animations in Qt cannot be achieved using QtStylesheets. Either use QML or use QStyledItemDelegate and a state machine.
/*CustomItemDelegate*/
int state;
enum states{
animating,
normal
}
void setstate(int state){
this->state = state;
/*Start animation depending on state ,by starting a QTimer and calling
repaint when the timer expires,also change animation variables like opacity ,
angle etc etc*/
}
void paint(QPainter *painter, const QStyleOptionViewItem &option,
const QModelIndex &index) const{
switch(state){
case animating:
break;
case normal;
break;
}
}
....
/*CustomListView*/
slots:
void dataChanged ( const QModelIndex & topLeft, const QModelIndex & bottomRight ){
( (CustomItemDelegate)itemDelegate(topleft) )->setState(animating);
}
....
/*Mainwindow*/
connect(model,SIGNAL(datachanged(QModelIndex,QModelindex)),view,SLOTS(QModelindex,QModelindex));