当信号槽中使用自己定义的结构体或class类型时，需要先注册
    摘自链接

    源码目录：D:\workspace\qRegisterMetaType_demo

    1. #ifndef MYWIDGET_H
    2. #define MYWIDGET_H
    4. #include <QWidget>
    6. namespace Ui {
    7. class MyWidget;
    8. }
    10. struct MyData{
    11.     QString str;
    12. };
    14. Q_DECLARE_METATYPE(MyData)
    16. class MyWidget : public QWidget
    17. {
    18.     Q_OBJECT
    20. public:
    21.     explicit MyWidget(QWidget *parent = 0);
    22.     ~MyWidget();
    24. signals:
    25.     void sendData(MyData myWidget);
    27. public slots:
    28.     void textChanged(QString str);
    30. private:
    31.     Ui::MyWidget *ui;
    32.     QString m_str;
    34. };
    36. #endif // MYWIDGET_H
    41. #include "mywidget.h"
    42. #include "ui_mywidget.h"
    43. #include <QDebug>
    45. MyWidget::MyWidget(QWidget *parent) :
    46.     QWidget(parent),
    47.     ui(new Ui::MyWidget)
    48. {
    49.     ui->setupUi(this);
    50.     connect(ui->lineEdit,SIGNAL(textChanged(QString)),this,SLOT(textChanged(QString)));
    52.     qDebug() << "Id:" << qRegisterMetaType<MyData>();
    53. }
    55. MyWidget::~MyWidget()
    56. {
    57.     delete ui;
    58. }
    60. void MyWidget::textChanged(QString str)
    61. {
    62.     MyData myData;
    63.     myData.str=str;
    64.     sendData(myData);
    65. }
    1. #ifndef WIDGET_H
    2. #define WIDGET_H
    4. #include "mywidget.h"
    6. class MyWidget;
    8. namespace Ui {
    9. class Widget;
    10. }
    12. class Widget : public QWidget
    13. {
    14.     Q_OBJECT
    16. public:
    17.     explicit Widget(QWidget *parent = 0);
    18.     ~Widget();
    20. public slots:
    21.     void btnClicked();
    22.     void receiverData(MyData var);
    24. private:
    25.     Ui::Widget *ui;
    27.     MyWidget *m_mywidget;
    28. };
    31. #endif // WIDGET_H
    34. #include "widget.h"
    35. #include "ui_widget.h"
    37. Widget::Widget(QWidget *parent) :
    38.     QWidget(parent),
    39.     ui(new Ui::Widget)
    40. {
    41.     ui->setupUi(this);
    42.     m_mywidget=new MyWidget;
    43.     connect(ui->pushButton,SIGNAL(clicked(bool)),this,SLOT(btnClicked()));
    44.     connect(m_mywidget,SIGNAL(sendData(MyData)),this,SLOT(receiverData(MyData)),Qt::QueuedConnection);
    45. }
    47. Widget::~Widget()
    48. {
    49.     delete ui;
    50. }
    52. void Widget::btnClicked()
    53. {
    54.     m_mywidget->show();
    55. }
    57. void Widget::receiverData(MyData var)
    58. {
    59.     ui->lineEdit->setText(var.str);
    60. }
    1. #include "widget.h"
    2. #include <QApplication>
    4. int main(int argc, char *argv[])
    5. {
    6.     QApplication a(argc, argv);
    7.     Widget w;
    8.     w.show();
    10.     return a.exec();
    11. }