QT学习之 如何启动一个线程
先给出相关代码，然后加以分析
//*************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************//
//***********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************//
//***********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************//
//***********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()函数是的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