Passing of Qt custom data types in signals and slots

Qt signal and slot function parameters can only be based on Qt's basic types, such as QString, int, bool, etc. If you want to pass a custom type, it will not work by default.

Take the structure as an example below to realize the transfer of structure type data

head File:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include<QMetaType>
#include<QDebug>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
private:
    Ui::MainWindow *ui;
    typedef struct
    {
        QString name;
        QString color;
    }MyStruct;


private slots:
    void on_testBtn_clicked();

signals:
    void AddDocItemSignalNew(MyStruct variant);

private slots:
    void AddDocItemNew(MyStruct variant);


};

#endif // MAINWINDOW_H

cpp file

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    qRegisterMetaType<MyStruct>("MyStruct");

    connect(this, SIGNAL(AddDocItemSignalNew(MyStruct)),this, SLOT(AddDocItemNew(MyStruct)));
            
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_testBtn_clicked()
{
    MyStruct myStruct;
    myStruct.color = "red";
    myStruct.name = "name";
    emit AddDocItemSignalNew(myStruct);

}

void MainWindow::AddDocItemNew(MyStruct variant)
{
    qDebug()<<variant.color<<variant.name;
}

Compared with the traditional int and other types, only increased

qRegisterMetaType<MyStruct>("MyStruct");

After packaging in this way, we can use Qt's signal and slot functions to pass custom data structures.