对于在Qt中使用多线程的方法有好多种,但是最常用的是继承QThread和moveToThread,这两种各有各的优缺点,但是对于他们的接口所在线程,下面进行说明 一下:
## QThread
如果要使用QThread进行多线程操作,就必须要写QThread的子类,在子类中的run函数中进行业务逻辑的处理
class WorkThread : public QThread
{
Q_OBJECT
public:
explicit WorkThread(QObject* parent = nullptr);
protected:
void run();
};
WorkThread::WorkThread(QObject* parent)
: QThread(parent)
{
std::cout << "QThread:" << QThread::currentThread() << "\tID:" << QThread::currentThreadId() << std::endl;
this->start();
}
void WorkThread::run()
{
std::cout << "run:" << QThread::currentThread() << "\tID:" << QThread::currentThreadId() << std::endl;
exec();
}

从上面的图片中可以看到,其实在QThread的子类中,除了run函数的执行是在单独的线程中进行的,其他的函数都是在主线程中
## moveToThread
使用moveToThread时,写一个工作类,这个类继承QObject,写一个共有属性的槽函数,在外部进行调用,在主线程中定义一个QThread对象,调用线程的start进行启动,定义一个工作类的对象,工作类对象调用moveToThread,移动到子线程,进行业务逻辑的处理
class Work : public QObject
{
Q_OBJECT
public:
explicit Work(QObject* parent = nullptr);
public slots:
void onDoWork();
private:
};
Work::Work(QObject* parent)
: QObject(parent)
{
std::cout << u8"work:" << QThread::currentThread() << "\tID:" << QThread::currentThreadId() << std::endl;
}
void Work::onDoWork()
{
std::cout << u8"work thread:" << QThread::currentThread() << "\tID:" << QThread::currentThreadId() << std::endl;
}
在主线程中应用:
Work* pwork = new Work();
pwork->moveToThread(&m_thread);
m_thread.start();
connect(this, &BlueTooth::sigDoWork, pwork, &Work::onDoWork);
其中m_thread这是QThread的对象,是类的成员变量

由上图可以看出,工作类的函数都是在主线程中,除了对外的共有槽函数是在子线程中
## QRunnable
关于QRunnable使用也是要写QRunnable的子类,在子类中实现纯虚接口run,在run中进行业务逻辑处理,它的启动是由线程池进行启动
class WorkRunnable : public QRunnable
{
public:
explicit WorkRunnable();
protected:
void run();
};
WorkRunnable::WorkRunnable()
: QRunnable()
{
std::cout << "WorkRunnable:" << QThread::currentThread() << "\tID:" << QThread::currentThreadId() << std::endl;
}
void WorkRunnable::run()
{
std::cout << "QRunnable:" << QThread::currentThread() << "\tID:" << QThread::currentThreadId() << std::endl;
}
主线程中调用如下:
WorkRunnable* pRunnable = new WorkRunnable();
QThreadPool::globalInstance()->start(pRunnable);

上图可以看出,还是run函数中的内容在子线程中,其他的都是在主线程中