Qt 窗体间传值（代码备份）

　　刚开始看的时候看的云里雾里的，现在稍微明白一点了。现在假设有一个form,一个MainWindow,如图所示：

　　实现点击PushButton,将文本框中的内容传输到MainWindow中，显示为Label。界面我已经提前画好。下面是备份代码：

form.h:

#ifndef FORM_H
#define FORM_H

#include <QWidget>

namespace Ui {
class Form;
}

class Form : public QWidget
{
    Q_OBJECT

public:
    explicit Form(QWidget *parent = 0);
    ~Form();

signals:
    void sendData(QString);

private slots:

    void on_sendBtn_clicked();

private:
    Ui::Form *ui;
};

#endif // FORM_H

form.cpp:

#include "form.h"
#include "ui_form.h"

Form::Form(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Form)
{
    ui->setupUi(this);
}

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

void Form::on_sendBtn_clicked()
{
     emit sendData(ui->lineE->text());

}

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "form.h"
namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
private slots:
    void receiveData(QString data);
private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

MainWindow.cpp:

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

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    //传值测试
    Form *form=new Form;
    form->setGeometry(100,300,400,400);
    form->show();
   connect(form,SIGNAL(sendData(QString)),this,SLOT(receiveData(QString)));

}

MainWindow::~MainWindow()
{
    delete ui;
}
void MainWindow::receiveData(QString data)
{
    ui->label->setText(data);
}

main.cpp:

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}