QT 多线程信号与槽（一）

来源：互联网发布：知错改错不认错下一句编辑：程序博客网时间：2024/04/28 21:29

1.一个主界面（主线程），一个次线程，次线程通过信号向主线程传递递增变量，主线程将它显示出来

mythread.h

#include <QThread>

#include <QDebug>

class Mythread : public QThread

    Q_OBJECT

public:

    Mythread();

protected:

    void run();

private:

    int i;

signals:

    void signal_add_int(QString);

};

mythread.cpp

#include "mythread.h"

#include <QDebug>

Mythread::Mythread()

    i = 0;

void Mythread::run()

    while(1)

        i++;

        QString str = QString::number(i,10);

        emit signal_add_int(str);

        sleep(1);

        qDebug()<<"run thread:" <<QThread::currentThreadId();

mainwindow.h

#include <QMainWindow>
#include "mythread.h"
namespace Ui {
    class MainWindow;
}
class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
private:
    Ui::MainWindow *ui;
    Mythread thread;
private slots:
    void set_lineEdit_text(QString);
    void start_thread();
};
mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    connect(&thread,SIGNAL(signal_add_int(QString)),this,SLOT(set_lineEdit_text(QString)),Qt::QueuedConnection);
    connect(ui->pushButton,SIGNAL(clicked()),this,SLOT(start_thread()));
    qDebug()<<"MainWindow:" <<QThread::currentThreadId();
}
MainWindow::~MainWindow()
{
    delete ui;
}
void MainWindow::set_lineEdit_text(QString str)
{
    ui->lineEdit->setText(str);
    qDebug()<<"from thread slot:" <<QThread::currentThreadId();
}
void MainWindow::start_thread()
{
    thread.start();
}
打印结果：
MainWindow: 3062654672 from thread slot: 3062654672 run thread: 3017550736 from thread slot: 3062654672 run thread: 3017550736 from thread slot: 3062654672 run thread: 3017550736 from thread slot: 3062654672 
结论：
     主线程运行thread.start()后，次线程启动，进入到次线程中，
     次线程发送信号给主线程，主线程接收到该信号，进入槽函数，该槽函数也在主线程中运行。
     次线程的开始和结束都在run函数中开始和结束