ComboBox with Checkboxes inside, C++ Qt, select/unselect all checkboxes - c++

Question

I wrote a simple combobox with checkboxes as its items. When I select an item and press button, it shows what item I selected. But I would like to do something like this: I have an item called "all" - when I select it, all other items should be selected, and when I unselect it, all others items should be unselected. Any ideas?
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QStandardItemModel>
#include <QComboBox>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
QStandardItemModel *model;
private slots:
void buttonclicked();
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <iostream>
#include <QDebug>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
this->model = new QStandardItemModel(4, 1); // 4 rows, 1 col
for (int r = 0; r < 4; ++r)
{
QStandardItem* item;
if(r == 0)
item = new QStandardItem(QString("All"));
else
item = new QStandardItem(QString("Item %0").arg(r));
item->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled);
item->setData(Qt::Unchecked, Qt::CheckStateRole);
model->setItem(r, 0, item);
}
ui->comboBox->setModel(model);
connect(ui->pushButton, SIGNAL(clicked()), this, SLOT(buttonclicked()));
}
void MainWindow::buttonclicked()
{
unsigned int i;
for(i=0; i<ui->comboBox->count(); i++)
{
QModelIndex index = ui->comboBox->model()->index(i, 0);
QVariant v = index.data(Qt::CheckStateRole);
int j = v.toInt();
if(j == 2)
{
QModelIndex ii = ui->comboBox->model()->index(i, 0);
QString text = ii.data(Qt::DisplayRole).toString();
qDebug() << text;
}
}
qDebug()<<"";
}
MainWindow::~MainWindow()
{
delete ui;
}
main.cpp
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
ui file
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>300</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralWidget">
<widget class="QComboBox" name="comboBox">
<property name="geometry">
<rect>
<x>100</x>
<y>50</y>
<width>201</width>
<height>23</height>
</rect>
</property>
</widget>
<widget class="QPushButton" name="pushButton">
<property name="geometry">
<rect>
<x>110</x>
<y>100</y>
<width>181</width>
<height>23</height>
</rect>
</property>
<property name="text">
<string>Check what was selected</string>
</property>
</widget>
</widget>
<widget class="QMenuBar" name="menuBar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>20</height>
</rect>
</property>
</widget>
<widget class="QToolBar" name="mainToolBar">
<attribute name="toolBarArea">
<enum>TopToolBarArea</enum>
</attribute>
<attribute name="toolBarBreak">
<bool>false</bool>
</attribute>
</widget>
<widget class="QStatusBar" name="statusBar"/>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>
It looks like this:

Answer 1

Implement a qtslot for this button such that when it is clicked/triggered you will iterate over all of the checkboxes within the desired combobox and edit their checked state.

Answer 2

I have been learning how to use model subclassing while trying replicate the checkbox list using your code and have found a way to trigger a signal when checked status in any of the checkboxes populating the list changes.
Declaring a public slot in MainWindow.h:
public slots:
void itemCheck(QModelIndex a, QModelIndex b);
Implementing the slot in MainWindow.cpp:
void MainWindow::void itemCheck(QModelIndex a, QModelIndex b)
{
qDebug() << "check event";
}
And connecting this new slot to the model's dataChanged signal:
connect(ui->comboBox->model(), SIGNAL(dataChanged(QModelIndex, QModelIndex, QVector<int>)), this, SLOT(itemCheck(QModelIndex, QModelIndex)));
I think, it is possible to filter the event for the "All" checkbox and set the other ones appropriately.
Managed to get it working:
void MainWindow::itemCheck(QModelIndex a, QModelIndex b)
{
qint16 i;
QModelIndex cycleIndex;
// if "All" checked
if (a.row() == 0)
{
// blocking new dataChanged singnal while managing other checkboxes
ui->comboBox->model()->blockSignals(true);
// setting other checkboxes appropriately
if (a.data(Qt::CheckStateRole).toBool())
{
for (i = 1; i<ui->comboBox->count(); i++)
{
cycleIndex = ui->comboBox->model()->index(i, 0);
ui->comboBox->model()->setData(cycleIndex, Qt::Checked, Qt::CheckStateRole);
}
} else
{
for (i = 1; i<ui->comboBox->count(); i++)
{
cycleIndex = ui->comboBox->model()->index(i, 0);
ui->comboBox->model()->setData(cycleIndex, Qt::Unchecked, Qt::CheckStateRole);
}
}
ui->comboBox->model()->blockSignals(false);
}
}
Hope this will help someone learning Qt from scratch.