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
?
?
//*************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_OBJECTpublic: 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
?
?