Qt - emit a signal from a c++ thread

Question

I want to emit a signal from a C++ thread (std::thread) in Qt.

How can I do it?

Answer 1

class MainForm : public QMainWindow
{
    Q_OBJECT

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

private:
signals:
    void signalSendButtonEnable(bool);

private slots:
    void singalReceiveButtonEnable(bool);


};

MainForm::MainForm(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainForm), status_{false}, io_context_{}, timer_{io_context_}
{
    ui->setupUi(this);

    // bind SIGNAL & SLOT
    connect(this, SIGNAL(signalSendButtonEnable(bool)), this, SLOT(singalReceiveButtonEnable(bool)));
}

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

void MainForm::singalReceiveButtonEnable(bool status){  //recv signal
    qDebug() << "singalReceiveButtonEnable";
    this->ui->btnConnect->setEnabled(status);
}

void MainForm::start(){
    std::thread t([](){
        sleep(20);
        emit signalSendButtonEnable(true);   //send signal
    });
    t.detach();
}