get child from parent in Qtreeview - c++

Question

I am developing a Qt application using QTreeView and QFileSystemModel.
I am able to get the parent's child till one level but I am not able to get the parent's child's child.
For eg:
C is child of B,
B is child of A
I am able to get B as A's child but I also want C as A's Child.
I want like this C->B->A.
Can someone give some input regarding this and help me out.
Thanks in advance.
//QItemSelectionModel *sel = ui->dir_tree->selectionModel();
QStringList strings = extractStringsFromModel(ui->dir_tree->model(), ui->dir_tree->rootIndex());
QFileSystemModel* model = (QFileSystemModel*)ui->dir_tree->model();
QModelIndexList indexlist = ui->dir_tree->selectionModel()->selectedIndexes();
QVariant data;
//QList<QModelIndex> modelindex(indexlist);
int row = -1;
for(int i=0; i<indexlist.size();i=i+4)
{
QModelIndex mi=indexlist.at(i);
info1 = model->fileInfo(mi);
QString childstr = info1.filePath();
QString childname = info1.fileName();
QModelIndex mi2= indexlist.at(i).parent();
info = model->fileInfo(mi2);
QString parentstr = info.filePath();
QString parentname = info.fileName();
QStringList childlist;
for(int j=0;j<model->rowCount(indexlist.at(i));j++)
{
QModelIndex mi3 = indexlist.at(i).child(j, 0);
info2 = model->fileInfo(mi3);
QString childrenstr = info2.filePath();
childlist << childrenstr;
qDebug()<<"parents' children"<<childrenstr<<j;
}
}

Answer 1

I like to use recursion for this kind of thing:
void MyTreeView::GetAllChildren(QModelIndex &index, QModelIndexList &indicies)
{
indicies.push_back(index);
for (int i = 0; i != model()->rowCount(index); ++i)
GetAllChildren(index.child(i,0), indicies);
}
Usage (from somewhere inside the tree view):
QModelIndexList list;
GetAllChildren(model()->index(0,0), list);

Answer 2

Getting all children breadth-first:
QModelIndexList children;
// Get top-level first.
for ( int i = 0; i < model->rowCount(); ++i ) {
children << model->index( i, 0 ); // Use whatever column you are interested in.
}
// Now descend through the generations.
for ( int i = 0; i < children.size(); ++i ) {
for ( int j = 0; j < model->rowCount( children[i] ); ++j ) {
children << children[i].child( j, 0 );
}
}
Getting all parents from a child:
QModelIndexList parents;
parents << child.parent();
while ( parents.last().isValid() ) {
parents << parents.last().parent();
}
Please note, I haven't tried these samples!

Answer 3

//Delete
QList<QTreeWidgetItem *> selected = ui->twg->selectedItems();
QTreeWidgetItem *item = selected.first();
QTreeWidgetItem *parent = item->parent();
if(parent) {
int index = parent->indexOfChild(item);
delete parent->takeChild(index);
}
//Add
QList<QTreeWidgetItem *> selected = ui->twg->selectedItems();
QTreeWidgetItem *item = selected.first();
QTreeWidgetItem *parent = item->parent();
if(parent) {
QTreeWidgetItem *tmp = new QTreeWidgetItem(parent);
tmp->setText(0, "Dude");
parent->addChild(tmp);
}