Qt基础开发之Qt多线程类QThread与Qt定时器类QTimer的详细方法与实例

[virtual protected] void QThread::run()
 /*
 * 基类QThread的run函数只是简单启动exec()消息循环
 */

#include <QApplication>
#include <QThread>
#include <QDebug>
class MyThread : public QThread
{
public:
 void run()
 {
  qDebug() << "QThread begin" << endl;
  qDebug() << "child thread" << QThread::currentThreadId() << endl;
  QThread::sleep(5);
  qDebug() << "QThread end" << endl;
  exec();
 }
};
​
int main(int argc, char** argv)
{
 QApplication app(argc, argv);
​
 MyThread thread;
 thread.start();
 qDebug() << "main thread" << QThread::currentThreadId() << endl;
 QThread::sleep(5);
 qDebug() << "main thread" << QThread::currentThreadId() << endl;
 thread.quit();
 qDebug() << "main thread thread.quit()" << endl;
 tread.wait();
 qDebug() << "main thread thread.wait()" << endl;
 return app.exec();
}

#ifndef MYWORK_H
#define MYWORK_H
#include <QThread>
#include <QDebug>
class MyWork : public QObject
{
 Q_OBJECT
public slots:
 void workSlot()
 {
  qDebug() << "QThread begin" << endl;
  qDebug() << "child thread" << QThread::currentThreadId() << endl;
  QThread::sleep(5);
  qDebug() << "QThread end" << endl;
 }
};
#endif // MYWORK_H

#include <QApplication>
#include <QThread>
#include <QDebug>
#include "mywork.h"
​
int main(int argc, char** argv)
{
 qDebug() << "main thread" << QThread::currentThreadId() << endl;
 QApplication app(argc, argv);
 QThread thread;
 MyWork work;
 work.moveToThread(&thread);
 QObject::connect(&thread, SIGNAL(started()), &work, SLOT(workSlot()));
 thread.start();
 
 QThread::sleep(6);
 qDebug() << "thread is runing" << thread.isRunning() << endl;
 thread.quit(); //调用quit让线程退出消息循环,否则线程一直在exec循环中
 thread.wait(); //调用完quit后紧接着要调用wait来回收线程资源
 qDebug() << "thread is runing" << thread.isRunning() << endl;
​
 return app.exec();
}

#ifndef MYWORK_H
#define MYWORK_H
​
#include <QThread>
#include <QDebug>
class MyWork : public QObject
{
 Q_OBJECT
public:
​
 ~MyWork() { qDebug() << __FUNCTION__ << endl; }
public slots:
 void workSlot()
 {
  while(1)
  {
   qDebug() << "Work begin" << endl;
   QThread::sleep(5);
   qDebug() << "work end" << endl;
  }
 }
 void otherWorkSlot()
 {
  qDebug() << "otherWork begin" << endl;
  QThread::sleep(5);
  qDebug() << "otherWork end" << endl;
 }
​
​
};
​
#endif // MYWORK_H

#ifndef WIDGET_H
#define WIDGET_H
​
#include <QWidget>
#include "mywork.h"
​
class Widget : public QWidget
{
 Q_OBJECT
​
public:
 Widget(QWidget *parent = 0);
 ~Widget();
private:
 QThread *_thread;
 MyWork * _myWork;
};
​
#endif // WIDGET_H

#include "widget.h"
#include <QPushButton>
#include "mywork.h"
#include <QThread>
#include <QHBoxLayout>
​
Widget::Widget(QWidget *parent)
 : QWidget(parent)
{
 _myWork = new MyWork;
 _thread = new QThread(this);
 _myWork->moveToThread(_thread);
 _thread->start();
​
 QPushButton *pb0 = new QPushButton("work", this);
 QPushButton *pb1 = new QPushButton("pb", this);
 QHBoxLayout *hBox = new QHBoxLayout(this);
 hBox->addWidget(pb0);
 hBox->addWidget(pb1);
 this->setLayout(hBox);
​
 /*发射信号给在另外一个线程的对象的队列中*/
 connect(pb0, SIGNAL(clicked()), _myWork, SLOT(workSlot()));
 connect(pb1, SIGNAL(clicked()), _myWork, SLOT(otherWorkSlot()));
​
 /*推荐用法释放内存*/
 //connect(_thread, SIGNAL(finished()), _myWork, SLOT(deleteLater()));
​
}
​
Widget::~Widget()
{
 _myWork->deleteLater(); //一定要在QThread线程退出之前
 _thread->quit();
 _thread->wait();
}

QMutex mutex; //这对象一般定义在多个线程能访问的地方
mutex.lock(); //多个线程调用这个函数去获取锁，没有获取到的线程，将阻塞等待在这个函数上。
mutex.unlock(); //释放锁

bool QMutex::tryLock(int timeout = 0)
/*
*参数 int timeout:等到timeout毫秒，不管有没获取到锁都返回，timeout为0时，直接返回。
*返回值 true代表获取到锁，false没有获取到
*/

QMutex mutex;
void func()
{
 QMutexLocker locker(_mutex); //QMutexLocker最好实例化成栈对象，释放之前将QMutex解锁。 
}

QSemaphore sem(2) //初始化信号量为2
sem.acquire(); //信号量部位0的时候，调用这个函数会让信号量-1，一旦信号量为零，阻塞等待
semaphore.release(); //使信号量+1

void start(int msec)
/*
*定时msec毫秒后，发射timeout()信号
*/

#include "dialog.h"
#include <QTimer>
#include <qdebug.h>
Dialog::Dialog(QWidget *parent)
 : QDialog(parent)
{
 QTimer *timer = new QTimer(this);
 connect(timer, SIGNAL(timeout()), this, SLOT(doSomeThing()));
 timer->start(3000);
 
}
void Dialog::doSomeThing()
{
 qDebug() << __FUNCTION__ << endl;
}
​
Dialog::~Dialog()
{
​
}