Cancel a cell value in a QTableView - c++

Question

How can I delete a value from a cell in a QTableView?
I created a QTableView but if I press the cancel button of the keyboard on the selected cell nothing happens.
If I want to delete that value I have to double-click the cell and press cancel but I want to delete the value without the double-click, just selecting the cell and press Canc.
Is keyEvent->key() useful?
#Chernobyl
MAINWINDOW.H
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QKeyEvent>
#include <QTableView>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0) ;
~MainWindow();
QTableView *griglia;
protected:
bool eventFilter(QObject *obj, QEvent *event);
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
MAINWINDOW.CPP
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent),ui(new Ui::MainWindow)
{
ui->setupUi(this);
qApp->installEventFilter(this);
}
bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
if(obj == griglia && event->type() == QEvent::KeyPress)
{
QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
if(keyEvent->key() == Qt::Key_Cancel)
{
QModelIndex in =griglia->currentIndex();
griglia->model()->setData(in," ");
}
}
return QObject::eventFilter(obj, event);
}
MainWindow::~MainWindow()
{
delete ui;
}
MAIN.CPP
#include "mainwindow.h"
#include "itemdelegate.h"
#include "mymodel.h"
#include <QApplication>
#include <QtGui>
#include <QtCore>
#include <QtWidgets>
#include <QFile>
#include <QString>
#include <QTextStream>
#include <QIdentityProxyModel>
#include <QRegExpValidator>
#define GRIGLIA_RX "^[F0-9]|1[0-9]|2[0-4]$"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QFile styleFile( "style.qss" );
styleFile.open( QFile::ReadOnly );
QString style( styleFile.readAll() );
a.setStyleSheet( style );
QWidget *mainWindow = new QWidget;
QStandardItemModel *model = new QStandardItemModel(48,33);
QTableView *griglia = new QTableView;
griglia->setModel(model);
QPushButton *calcola = new QPushButton;
calcola->setText("CALCOLA");
QVBoxLayout *layout = new QVBoxLayout;
layout->addWidget(griglia);
layout->addWidget(calcola);
mainWindow->setLayout(layout);
ItemDelegate *itDelegate = new ItemDelegate;
griglia->setItemDelegate(itDelegate);
mainWindow->showMaximized();
return a.exec();
}
I added QDebug line but if I press Canc no message appears

Answer 1

Use next event filter as in my example or reimplement keyPressEvent:
bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
if(obj == ui->tableView && event->type() == QEvent::KeyPress)
{
QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
if(keyEvent->key() == Qt::Key_Shift)
{
qDebug() << "works";
QModelIndex in = ui->tableView->currentIndex();
ui->tableView->model()->setData(in,"");
//ui->tableView->model()->setData(ui->tableView->currentIndex(),""); //or just this
}
}
return QObject::eventFilter(obj, event);
}
To use eventFilter you should also:
protected:
bool eventFilter(QObject *obj, QEvent *event);//in header
and
qApp->installEventFilter(this);//in constructor
You can use Qt::Key_Shift or Qt::Key_Cancel or something else.
EDIT
MAINWINDOW.H
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QKeyEvent>
#include <QTableView>
#include "itemdelegate.h"
#include "mymodel.h"
#include <QApplication>
#include <QtGui>
#include <QtCore>
#include <QtWidgets>
#include <QFile>
#include <QString>
#include <QTextStream>
#include <QIdentityProxyModel>
#include <QRegExpValidator>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0) ;
~MainWindow();
QTableView *griglia;
protected:
bool eventFilter(QObject *obj, QEvent *event);
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
MAINWINDOW.CPP
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent),ui(new Ui::MainWindow)
{
ui->setupUi(this);
QWidget *mainWindow = new QWidget;
QStandardItemModel *model = new QStandardItemModel(48,33);
griglia = new QTableView;
griglia->setModel(model);
QPushButton *calcola = new QPushButton;
calcola->setText("CALCOLA");
QVBoxLayout *layout = new QVBoxLayout;
layout->addWidget(griglia);
layout->addWidget(calcola);
mainWindow->setLayout(layout);
ItemDelegate *itDelegate = new ItemDelegate;
griglia->setItemDelegate(itDelegate);
this->setCentralWidget(mainWindow);
qApp->installEventFilter(this);
}
bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
if(obj == griglia && event->type() == QEvent::KeyPress)
{
QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
if(keyEvent->key() == Qt::Key_Cancel)
{
QModelIndex in =griglia->currentIndex();
griglia->model()->setData(in," ");
}
}
return QObject::eventFilter(obj, event);
}
MainWindow::~MainWindow()
{
delete ui;
}
MAIN.CPP
#include "mainwindow.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QFile styleFile( "style.qss" );
styleFile.open( QFile::ReadOnly );
QString style( styleFile.readAll() );
a.setStyleSheet( style );
MainWindow my;
my.showMaximized();
return a.exec();
}
Now you should see "works" and cell should be cleared, another code optimization do by yourself.
Addition for multiple selection:
if(obj == ui->tableView && event->type() == QEvent::KeyPress)
{
QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
if(keyEvent->key() == Qt::Key_Shift)
{
qDebug() << "Up";
//ui->tableView->model()->setData(ui->tableView->currentIndex(),"");
QList<QModelIndex> index = ui->tableView->selectionModel()->selectedIndexes();
for(int i = 0; i < index.size(); i++)
ui->tableView->model()->setData(index.at(i),"");
}
}