QT GUI（主）线程与子线程之间的通信——使用跨线程的信号槽

在主线程上，可以控制子线程启动，停止，清零

如果子线程启动的话，每一秒钟会向主线程发送一个数字，让主线程更新界面上的数字。

程序截图：

上代码：

#include <QtGui>
#include <QtCore>
#include <windows.h>

class Thread : public QThread
{
    Q_OBJECT
private:
    int number;
protected:
    void run();
public:
    Thread(QObject *parent=0);
    ~Thread();
signals:
    void UpdateSignal(int num);
    public slots:
        void ResetSlot();
};

class Widget : public QWidget
{
    Q_OBJECT
private:
    QLabel *label;
    QPushButton *startButton;
    QPushButton *stopButton;
    QPushButton *resetButton;
    Thread *myThread;
    int number;
public:
    Widget(QWidget *parent = 0);
    ~Widget();
signals:
    void ResetSignal();
    public slots:
        void ClearSlot();
        void StartSlot();
        void StopSlot();
        void UpdateSlot(int num);
};

Thread::Thread(QObject *parent)
{
    number = 0;
}

Thread::~Thread()
{

}

void Thread::run()
{
    while(1)
    {
        //开启一个死循环，让number每秒自增1，并通过发送UpdateSignal信号通知主界面更新
        emit UpdateSignal(number);
        number++;
        sleep(1);
    }
}

void Thread::ResetSlot()
{
    number = 0;
    emit UpdateSignal(number);
}

Widget::Widget(QWidget *parent)
{
    //设置界面布局
    startButton = new QPushButton("start");
    stopButton = new QPushButton("stop");
    resetButton = new QPushButton("reset");
    label = new QLabel("empty");
    myThread = new Thread;
    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(label);
    layout->addWidget(startButton);
    layout->addWidget(stopButton);
    layout->addWidget(resetButton);
    setLayout(layout);

    //连接各自信号糟
    connect(stopButton, SIGNAL(clicked()),
        this, SLOT(StopSlot()));
    connect(startButton, SIGNAL(clicked()),
        this, SLOT(StartSlot()));
    connect(resetButton, SIGNAL(clicked()),
        this, SLOT(ClearSlot()));
    connect(myThread, SIGNAL(UpdateSignal(int)),
        this, SLOT(UpdateSlot(int)));
    connect(this, SIGNAL(ResetSignal()),
        myThread, SLOT(ResetSlot()));


    setWindowTitle("Thread Test");
    resize(200, 200);
    myThread->start();

}

Widget::~Widget()
{

}

void Widget::StartSlot()
{
    myThread->start();
}

void Widget::StopSlot()
{
    myThread->terminate();
}

void Widget::UpdateSlot(int num)
{
    label->setText(QString::number(num));
}

void Widget::ClearSlot()
{
    emit ResetSignal();
}

#include "main.moc"

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    Widget *widget = new Widget;
    widget->show();
    return app.exec();
}