Qt QTreeView indexBelow does not work - qt

Question

As far as I understood, indexBelow function is used for navigating to the next item on a tree in Qt's QTreeView. I want to write two functions - one to move to next item, one to move to previous item in a DirModel based TreeView. However, indexBelow does only work once.
Considering ui is the UI variable, the following is my function to move to the next item
void MainWindow::moveDown (void)
{
QModelIndex index_it = ui->treeView->indexBelow(ui->treeView->currentIndex());
qDebug() << index_it.row();
if (index_it.isValid())
{
qDebug() << "Valid";
ui->treeView->setCurrentIndex(index_it);
ui->treeView->selectionModel()->select(index_it, QItemSelectionModel::ClearAndSelect | QItemSelectionModel::Rows);
}
}
When a button is pressed, this will be triggered and the tree will be navigated using buttons. This however, works only once, and afterwards stops working. Note that I want to be able to move to next item even if there is an expanded child. Any pointers and help is greately appreciated.

Answer 1

Just tried your code and it work fine.
MainWindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>
#include <QStandardItemModel>
#include <QFileSystemModel>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_pushButton_clicked()
{
model->setReadOnly(false);
model->setSorting(QDir::DirsFirst |
QDir::IgnoreCase |
QDir::Name);
ui->treeView->setModel(model);
index = model->index("C:/");
// Set initial view of directory
// for the selected drive as expanded
ui->treeView->expand(index);
// Make it scroll to the selected
ui->treeView->scrollTo(index);
// Highlight the selected
ui->treeView->setCurrentIndex(ui->treeView->indexBelow(index));
// Resizing the column - first column
ui->treeView->resizeColumnToContents(0);
}
void MainWindow::on_pushButton_3_clicked()//<------Your function MoveDown
{
QModelIndex index_it = ui->treeView->indexBelow(ui->treeView
->currentIndex());
qDebug() << index_it.row();
if (index_it.isValid())
{
qDebug() << "Valid";
ui->treeView->setCurrentIndex(index_it);
ui->treeView->selectionModel()->select(index_it, QItemSelectionModel::ClearAndSelect | QItemSelectionModel::Rows);
}
}
And mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QModelIndex>
#include <QDirModel>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
emitProgress(int per)
{
emit signalProgress(per);
}
void on_pushButton_clicked();
void on_pushButton_3_clicked();
signals:
private:
Ui::MainWindow *ui;
QModelIndex index;
QDirModel* model = new QDirModel(this);
};