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(C++) QTreeViewExample2

 

QtQt CreatorLubuntu

 

QTreeView example 2: add a row and undo/redo this is an example to use a QTreeView.

 

Technical facts

 

Application type(s)

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Libraries used:

 

 

 

 

 

Qt project file: ./CppQTreeViewExample2/CppQTreeViewExample2.pro

 

QT       += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TEMPLATE = app

SOURCES += \
    qtdialog.cpp \
    qtmain.cpp \
    qtaddrowcommand.cpp

HEADERS  += qtdialog.h \
    qtaddrowcommand.h

FORMS    += qtdialog.ui

 

 

 

 

 

./CppQTreeViewExample2/qtaddrowcommand.h

 

#ifndef QTADDROWCOMMAND_H
#define QTADDROWCOMMAND_H

#include <QUndoCommand>

struct QStandardItemModel;
struct QAbstractItemView;

struct QtAddRowCommand : public QUndoCommand
{
  QtAddRowCommand(
    QStandardItemModel * const model,
    QAbstractItemView * const view);
  void redo();
  void undo();

  private:
  std::string m_text;
  QStandardItemModel * const m_model;
  QAbstractItemView  * const m_view;
};

#endif // QTADDROWCOMMAND_H

 

 

 

 

 

./CppQTreeViewExample2/qtaddrowcommand.cpp

 

#include "qtaddrowcommand.h"

#include <QAbstractItemModel>
#include <QAbstractItemView>
#include <QStandardItem>
#include <QStandardItemModel>

QtAddRowCommand::QtAddRowCommand(
  QStandardItemModel * const model,
  QAbstractItemView * const view)
  : m_model(model), m_view(view)
{

}

void QtAddRowCommand::redo()
{
  QStandardItem * const item = new QStandardItem;
  item->setText(m_text.c_str());
  m_model->appendRow(item);
  m_view->setCurrentIndex(item->index());
}

void QtAddRowCommand::undo()
{
  const int n_rows = m_model->rowCount();
  QStandardItem * const item = m_model->item(n_rows - 1);
  if (item) m_text = item->text().toStdString();
  m_model->removeRow(n_rows - 1);
}

 

 

 

 

 

./CppQTreeViewExample2/qtdialog.h

 

#ifndef QTDIALOG_H
#define QTDIALOG_H

#include <QDialog>

namespace Ui {
  class QtDialog;
}

struct QStandardItemModel;
struct QUndoStack;

class QtDialog : public QDialog
{
  Q_OBJECT
  
public:
  explicit QtDialog(QWidget *parent = 0);
  ~QtDialog();

protected:
  void keyPressEvent(QKeyEvent *);
  
private slots:
  void on_button_clicked();

private:
  Ui::QtDialog *ui;
  QStandardItemModel * const m_model;
  QUndoStack * const m_undo_stack;
};

#endif // QTDIALOG_H

 

 

 

 

 

./CppQTreeViewExample2/qtdialog.cpp

 

#include "qtdialog.h"

#include <QKeyEvent>

#include <QStandardItemModel>
#include <QStyledItemDelegate>
#include <QUndoStack>

#include "qtaddrowcommand.h"
#include "ui_qtdialog.h"

QtDialog::QtDialog(QWidget *parent) :
  QDialog(parent),
  ui(new Ui::QtDialog),
  m_model(new QStandardItemModel),
  m_undo_stack(new QUndoStack)
{
  ui->setupUi(this);
  ui->tree->setModel(m_model);
  ui->tree->setItemDelegate(new QStyledItemDelegate);
}

QtDialog::~QtDialog()
{
  delete ui;
  delete m_undo_stack;
}

void QtDialog::keyPressEvent(QKeyEvent * e)
{
  if ( (e->modifiers() & Qt::ControlModifier)
    && !(e->modifiers() & Qt::ShiftModifier)
    && e->key() == Qt::Key_Z)
  {
    m_undo_stack->undo();
  }
  if ( (e->modifiers() & Qt::ControlModifier)
    && (e->modifiers() & Qt::ShiftModifier)
    && e->key() == Qt::Key_Z)
  {
    m_undo_stack->redo();
  }
}

void QtDialog::on_button_clicked()
{
  QtAddRowCommand * const cmd = new QtAddRowCommand(m_model,ui->tree);
  m_undo_stack->push(cmd);

  ui->tree->scrollToBottom();

  const int n_rows = m_model->rowCount();
  QStandardItem * const item = m_model->item(n_rows - 1);
  ui->tree->edit(item->index());

}

 

 

 

 

 

./CppQTreeViewExample2/qtmain.cpp

 

#include <QApplication>
#include "qtdialog.h"

int main(int argc, char *argv[])
{
  QApplication a(argc, argv);
  QtDialog w;
  w.show();
  
  return a.exec();
}

 

 

 

 

 

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