1.一個主界面（主線程），一個次線程，次線程通過信號向主線程傳遞遞增變量，主線程將它顯示出來
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();
}打印結果：
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
結論：主線程運行thread.start()後，次線程啓動，進入到次線程中，
次線程發送信號給主線程，主線程接收到該信號，進入槽函數，該槽函數也在主線程中運行。
次線程的開始和結束都在run函數中開始和結束