Problem implementing back function with QfileSystemModel and QlistView

[gayandis]

Hi,

I have implemented file system back button function with following
@
void Dialog:n_pushButton_pressed()
{
QModelIndex indexedit=ui->listView->currentIndex();
QModelIndex indexparent=indexedit.parent();
qDebug()<<indexedit;
qDebug()<<indexparent;
ui->listView->setRootIndex(indexparent);

}@

but this is the output which i have got
@
QModelIndex(2,0,0x8920040,QFileSystemModel(0x87e00 a8) )
QModelIndex(1,0,0x86da1b8,QFileSystemModel(0x87e00 a8) )
QModelIndex(2,0,0x8920040,QFileSystemModel(0x87e00 a8) )
QModelIndex(1,0,0x86da1b8,QFileSystemModel(0x87e00 a8) )
QModelIndex(2,0,0x8920040,QFileSystemModel(0x87e00 a8) )
QModelIndex(1,0,0x86da1b8,QFileSystemModel(0x87e00 a8) )
QModelIndex(2,0,0x8920040,QFileSystemModel(0x87e00 a8) )
QModelIndex(1,0,0x86da1b8,QFileSystemModel(0x87e00 a8) )
QModelIndex(2,0,0x8920040,QFileSystemModel(0x87e00 a8) )
QModelIndex(1,0,0x86da1b8,QFileSystemModel(0x87e00 a8) )
QModelIndex(2,0,0x8920040,QFileSystemModel(0x87e00 a8) )
QModelIndex(1,0,0x86da1b8,QFileSystemModel(0x87e00 a8) )
QModelIndex(2,0,0x8920040,QFileSystemModel(0x87e00 a8) )
QModelIndex(1,0,0x86da1b8,QFileSystemModel(0x87e00 a8) )
QModelIndex(2,0,0x8920040,QFileSystemModel(0x87e00 a8) )
QModelIndex(1,0,0x86da1b8,QFileSystemModel(0x87e00 a8) )
QModelIndex(2,0,0x8920040,QFileSystemModel(0x87e00 a8) )
QModelIndex(1,0,0x86da1b8,QFileSystemModel(0x87e00 a8) )
QModelIndex(2,0,0x8920040,QFileSystemModel(0x87e00 a8) )
QModelIndex(1,0,0x86da1b8,QFileSystemModel(0x87e00 a8) )

@

in here back key works only once then button wont update .please help me with this issue ...Thanks