Qt如何实现多线程：https://www.cnblogs.com/azbane/p/11372531.html
September 5，2019
先抛出几个问题，用问题来引导思维导向：
1、继承的QObject子类，和QThread对象，是在哪个线程创建的？（即：QObject子类对象和QThread对象的依附线程是哪个？）
2、QThread在哪个线程运行？
3、QObject::moveToThread( QThread )后，QThread 的信号(started/finished)关联的QObject子类对象的函数（槽函数）哪个线程运行？
4、QObject::moveToThread( QThread ) 后，QThread的信号(started/finished)关联的依附线程对象的槽函数在哪个线程运行？
5、信号和槽的新版本，用lambda表达式处理信号的情况（QThread的信号(started/finished)关联的lambda），lambda对象运行在哪个对象？
看起来很复杂，其实并不可怕：想知道对象在哪个线程运行，有两种方式可用
1：QThread::currentThreadId() 返回16进制的线程ID (#include<QThread>)
2：std::this_thread::get_id() 返回10进制的线程ID （#include<iostream> #include <QThread>）
先给答案，再上例子说明， 最后给出遇到的错误情况。
上面跑出的5个问题的答案：
假定QObject子类对象和QThread对象都是在线程A中创建。
1、线程A。 调用std::this_thread::get_id
2、线程A。 调用QThread::currentThreadId， 需要由16进制转成10进制，再对比。
3、线程B。 假定线程id = B 。调用std::this_thread::get_id
4、线程A。 调用std::this_thread::get_id
5、线程B。 调用std::this_thread::get_id
例子主要信息说明：
类ShapeLayout:
有两个指针数据成员：GenerateGridFileWork * m_generateGridFileWork; QThread * m_generateGridFileWorkThread;
有一个函数成员：MakeGrid， 函数里面创建两个指针数据成员。
m_generateGridFileWork->moveToThread(m_generateGridFileWorkThread);
GenerateGridFileWork::slotsWork QThread::signals - started / finished
ShapeLayout.h ----------------------------------------------------------- class ShapeLayout : public QObject { Q_OBJECT public: void makeGrid(); public slots: void slotsThreadFininshed(); private: GenerateGridFileWork * m_GenerateGridFileWork = nullptr; QThread * m_GenerateGridFileWorkThread = nullptr; } ShapeLayout.cpp ----------------------------------------------------------- void ShapeLayout::makeGrid() { std::cout<<"ShapeLayout thread id is "<<std::this_thread::get_id()<<std::cout; //问题-1 m_GenerateGridFileWork = new GenerateGridFileWork ; m_GenerateGridFileWorkThread = new QThread; m_GenerateGridFileWork->moveToThread(m_GenerateGridFileWorkThread); QObject::connect(m_GenerateGridFileWorkThread, &QThread::started, m_GenerateGridFileWork , &GenerateGridFileWork::slotsWork); QObject::connect(m_GenerateGridFileWork, &GenerateGridFileWork::signalsWorkFinished, m_GenerateGridFileWorkThread, &QThread::quit); QObject::connect(m_GenerateGridFileWorkThread, &QThread::finished, this, &ShapeLayout::slotsThreadFininshed); QObject::connect(m_GenerateGridFileWorkThread, &QThread::started, []{ std::cout<<"connect thread-started signals lambda object thread id is"<<std::this_thread::get_id()<<std::cout; //问题-5 }); QObject::connect(m_GenerateGridFileWorkThread, &QThread::finished, []{ std::cout<<"connect thread-finishedsignals lambda object thread id is"<<std::this_thread::get_id()<<std::cout;//问题-5 }); std::cout<<"QThread thread id is "<<m_generateGridFileWorkThread->currentThreadId()<<std::cout; //问题-2 m_GenerateGridFileWorkThread->start(); } void ShapeLayout::slotsThreadFininshed(){ std::cout<<"connect slots function of the ShapeLayout attributable thread id is"<<std::this_thread::get_id()<<std::cout;//问题-4}GenerateGridFileWork.h ------------------------------------------------ class GenerateGridFileWork : public QObject { public slots: void slotsWork(); signals: void signalsWorkFinished(); } GenerateGridFileWork.cpp ------------------------------------------------ void GenerateGridFileWork::slotsWork() { std::cout<<"connect to slots function of QObject subObject thread id is "<<std::this_thread::get_id()<<std::cout;//问题-3 emit signalsWorkFinished(); }
调用ShapeLayout::makeGrid()； 一切都知道啦， 自己去运行一遍吧
OK perfect...
September 5, 2019追加一个问题：
moveToThread的方式实现的线程，作业完成后，针对QObject的子类对象和QThread对象的释放顺序有没有讲究？
转载于:https://www.cnblogs.com/azbane/p/11465466.html
