Qt学习之如何启动和终止一个线程

今天来看看Qt如何启动一个线程吧，代码就以精通Qt4编程的为例

先来给出每个文件的相关代码然后再加以分析

Cpp代码



//*************dialog.h**************//

#ifndef DIALOG_H

#define DIALOG_H

#include <QDialog>

#define MAXSIZE 5 //最大的线程数

class QDialogButtonBox;

class QProgressBar;

class QPushButton;

class WorkThread;

class ThreadDlg : public QDialog

{

Q_OBJECT

public:

ThreadDlg(QWidget *parent = 0);

public slots:

void start();

void stop();

private:

QPushButton *startButton;

QPushButton *quitButton;

QPushButton *stopButton;

QDialogButtonBox *buttonBox;

WorkThread* threadVector[MAXSIZE];

};

#endif

//***********end end end************//

Cpp代码



//***********mainwindow.h************//

#ifndef WORKTHREAD_H

#define WORKTHREAD_H

#include <QThread>

class WorkThread : public QThread

{

protected:

void run(); //重新实现run()函数

};

#endif

//***********end end end************//

Cpp代码



//***********dialog.cpp************//

#include <QtGui>

#include "workThread.h"

#include "dialog.h"

ThreadDlg::ThreadDlg(QWidget *parent)

: QDialog(parent)

{

startButton = new QPushButton(tr("开始"));

quitButton = new QPushButton(tr("退出"));

stopButton = new QPushButton(tr("停止"));

stopButton->setEnabled(false);

buttonBox = new QDialogButtonBox;

buttonBox->addButton(startButton, QDialogButtonBox::ActionRole);

buttonBox->addButton(stopButton, QDialogButtonBox::ActionRole);

buttonBox->addButton(quitButton, QDialogButtonBox::RejectRole);

connect(startButton, SIGNAL(clicked()), this, SLOT(start()));

connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));

connect(stopButton, SIGNAL(clicked()), this, SLOT(stop()));

QVBoxLayout *mainLayout = new QVBoxLayout;

mainLayout->addWidget(buttonBox);

setLayout(mainLayout);

setWindowTitle(tr("启动线程"));

}

void ThreadDlg::start()

{

for(int i=0;i<MAXSIZE;i++)

{

threadVector[i] = new WorkThread(); //创建线程

}

for(int i=0;i<MAXSIZE;i++)

{

threadVector[i]->start(QThread::LowestPriority); //启动线程同时设置它的优先级，当然也可以不带，使用默认的优先级

}

stopButton->setEnabled(true);

startButton->setEnabled(false);

}

void ThreadDlg::stop()

{

for(int i=0;i<MAXSIZE;i++)

{

threadVector[i]->terminate(); //终止线程

threadVector[i]->wait(); //阻塞等待

}

startButton->setEnabled(true);

stopButton->setEnabled(false);

}

//***********end end end************//

Cpp代码



//***********mainwindow.cpp************//

#include "workThread.h"

#include "dialog.h"

#include <QTextEdit>

#include <QDebug>

#include <stdio.h>

void WorkThread::run()

{

while(true)

for (int n = 0; n < 10;++n) {

printf("%d\n",n); //打印输出

}

}

//***********end end end************//

//***********main.cpp************//

#include <QApplication>

#include <QtCore>

#include "dialog.h"

int main(int argc, char *argv[])

{

QApplication app(argc, argv);

QTextCodec::setCodecForTr( QTextCodec::codecForName("gb2312"));

ThreadDlg dialog;

dialog.show();

return dialog.exec();

}

//***********end end end************//

以上代码简单，没有必要做过多的讲解，但是其中的“threadVector[i]->terminate(); ”有必要讲解下，terminate()函数的调用便不会立刻终止线程，因为线程的何时终止取决于系统的调度策略，所在在之后又调用了wait()函数是线程阻塞等待直到退出或者超时。
最后加以一点就是在.pro文件中加入一行代码才能成功运行：
CONFIG+=thread

本文来源：http://qimo601.iteye.com/blog/1287279