我如何在另一个线程Qt显示MessageBox

Question

这是我的代码:

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    testApp w;
    w.show();
    TestClass *test = new TestClass;
    QObject::connect(w.ui.pushButton, SIGNAL(clicked()), test, SLOT(something()));
    return a.exec();
}

TestClass.h

class TestClass: public QObject
{
    Q_OBJECT
    public slots:
        void something()
        {
            TestThread *thread = new TestThread;
            thread -> start();
        }
};

TestThread.h

class TestThread: public QThread
{
    Q_OBJECT
protected:
    void run()
    {
        sleep(1000);
        QMessageBox Msgbox;
        Msgbox.setText("Hello!");
        Msgbox.exec();
    }
};

如果我这样做，我看到错误

部件必须在GUI线程

中创建

我做错了什么?请帮帮我。我知道我不能改变gui在另一个线程，但我不知道在qt的结构为这个。

Answer 1

你做错了什么?

您正在尝试在非gui线程中显示小部件。

如何修复?

class TestClass: public QObject
{
    Q_OBJECT
    public slots:
        void something()
        {
            TestThread *thread = new TestThread();
            // Use Qt::BlockingQueuedConnection !!!
            connect( thread, SIGNAL( showMB() ), this, SLOT( showMessageBox() ), Qt::BlockingQueuedConnection ) ;
            thread->start();
        }
        void showMessageBox()
        {
            QMessageBox Msgbox;
            Msgbox.setText("Hello!");
            Msgbox.exec();
        }
};

class TestThread: public QThread
{
    Q_OBJECT
signals:
    void showMB();
protected:
    void run()
    {
        sleep(1);
        emit showMB();
    }
};