QT qcombobox add qccheckbox (drop-down list box insert check box, including source code + comments)

One 、 Drop down list box insert check box example figure

The following figure is an example of a drop-down list box with a check box , It contains added items , Checked items , Check the check box and other operations .

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Two 、 Source code

ComboBoxTest.h

#ifndef COMBOBOXTEST_H
#define COMBOBOXTEST_H

#include <QWidget>
#include <QListWidget>

namespace Ui {
    
class ComboBoxTest;
}

class ComboBoxTest : public QWidget
{
    
    Q_OBJECT

public:
    explicit ComboBoxTest(QWidget *parent = nullptr);
    ~ComboBoxTest();

private slots:
    /** * @brief on_addBtn_clicked  add to item Click the slot function  */
    void on_addBtn_clicked();

    /** * @brief on_comboBox_currentIndexChanged  Drop down list box switch option slot function  * @param index  Switched index Index position  */
    void on_comboBox_currentIndexChanged(int index);

private:
    Ui::ComboBoxTest    *ui;

    QListWidget         *m_listWidget;  //  Drop down list box 
};

#endif // COMBOBOXTEST_H

ComboBoxTest.cpp

#include "ComboBoxTest.h"
#include "ui_ComboBoxTest.h"

#include <QCheckBox>

ComboBoxTest::ComboBoxTest(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::ComboBoxTest)
{
    
    ui->setupUi(this);
    //  Set the window title 
    this->setWindowTitle("ComboBox With a check box ");

    //  establish QListWidget Object space 
    m_listWidget = new QListWidget;

    //  Set first model, And then in settings view, When I test, the reverse setting will collapse 
    //!  take comboBox Of model Object is set to QListWidget Object's model
    //!  because QListWidget Inherit QListView So it exists model object 
    ui->comboBox->setModel(m_listWidget->model());

    //!  take comboBox Of view Object is set to QListWidget object 
    //!  because QListWidget Inherit QListView So it's equivalent to View
    ui->comboBox->setView(m_listWidget);

    //!  Add an empty... Here item Used when the default value 
    //  establish QListWidgetItem Object and specify the parent object 
    QListWidgetItem *item = new QListWidgetItem(m_listWidget);
    //  take item Add to QListWidget In the object 
    m_listWidget->addItem(item);
}

ComboBoxTest::~ComboBoxTest()
{
    
    // Release QListWidget、ui Storage space 
    delete m_listWidget;
    delete ui;
}

void ComboBoxTest::on_addBtn_clicked()
{
    
    //  Get to add item The text displayed on the 
    QString text = ui->lineEdit->text();

    //  Return directly when the text is empty , Don't add 
    if(text.isEmpty())
    {
    
        return;
    }

    //!  Create check box object space 
    //!  Specify the parent object of the check box when creating , When its parent object is released, its child object pointer will be released first 
    QCheckBox *checkBox = new QCheckBox(m_listWidget);

    //  establish QListWidgetItem Object and pass in text and specify the parent object 
    QListWidgetItem *item = new QListWidgetItem(text, m_listWidget);
    // Set up item Center text 
    item->setTextAlignment(Qt::AlignCenter);

    // take item Add to QListWidget In the object 
    m_listWidget->addItem(item);
    // Set the check box to item in 
    m_listWidget->setItemWidget(item, checkBox);
}

void ComboBoxTest::on_comboBox_currentIndexChanged(int index)
{
    
    // Get the current index location item
    QListWidgetItem *item = m_listWidget->item(index);
    // When you get item Return for space time 
    if(nullptr == item)
    {
    
        return;
    }

    // Get the text of the current option 
    QString itemStr = item->text();

    // Get the... Of the checkbox where the current option is located widget object 
    QWidget *widget = m_listWidget->itemWidget(item);
    // take widget Object to checkBox object 
    QCheckBox *checkBox = dynamic_cast<QCheckBox *>(widget);
    // When you get checkBox Return for space time 
    if(nullptr == checkBox)
    {
    
        ui->textBrowser->append(" empty ");
        return;
    }

    // according to checkBox Get the text in the checked state of 
    QString checkBoxStr = checkBox->isChecked()? " Checked ": " Uncheck ";

    // Combine text
    QString text = QString(" Index position ：%1  Text ：%2  Selected state ：%3")
            .arg(index).arg(itemStr).arg(checkBoxStr);

    // Append text to the text column 
    ui->textBrowser->append(text);
}

summary

In this article on_comboBox_currentIndexChanged Got the checkbox object , You can make the judgment that the checkbox should have here , Or connect the slot function when creating the check box ; The details are in the notes , Read carefully if you are interested .

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notes ： This paper summarizes the problems encountered by the author in the process of programming , The content is for reference only , If there are any mistakes, please point out .
notes ： If there is any infringement , Please contact the author for deletion