Qt QThread两种方式的使用：1-继承QThread重写run函数； 2- 继承QObject并moveToThread && 消息和槽在线程和依附线程间的传递

2019年08月18日起笔

方式一：继承QThread重写run函数

MyThread.h
-----------------------------------
...
class MyThread : public QThread
{
protected:
　　void run();
}

MyThread.cpp
-----------------------------------
...
void MyThread::run()
{
    //do something    
    ...
    exec();
}

Main.cpp
------------------------------------
...
MyThread * myThread = new MyThread;
MyThread.start();
...

方式二：继承QObject并moveToThread

MyWork.h
--------------------------------------
class MyWork : public QObject
{
Q_OBJECT
public:
    explict MyWork(QObject * parent = nullptr);
public slots:
    void slotsDoWork();
};

MyWork.cpp
--------------------------------------
MyWork::MyWork(QObject *parent):QObject(parent)
{}

void MyWork::slotsDoWork()
{
      //do something
}

someWhere.cpp
--------------------------------------
...
QThread * thread = new QThread(this);
MyWork * myWork = new MyWork;

QObject::connect(thread, &QThread::started, myWork, &MyWork::slotsDoWork);
MyWork->moveToThread(thread);

thread->start();

/*
*深入：thread 和 myWork分别在哪个线程中运行？ ：https://www.cnblogs.com/azbane/p/11465466.html
*/

消息和槽在线程和依附线程间的传递：

首先说明：依附线程是指创建线程的线程。

情况一：线程发射消息，依附线程接收消息

　　　　一.1继承QThread重写run函数，小熊尝试失败，针对代码及编译错误消息如下：

MyThread.h
---------------------------------
signals:
    void signalsA();

MyThread.cpp
---------------------------------
void MyThread::run()
{
    ...
    emit signalsA();
    ...
}

编译错误：
---------------------------------
LNK2019：无法解析的外部符号＂public: void __thiscall MyThread::signalsA(void)＂（？signals@MyThread@@QAEXXZ），该符号在函数 " protected: virtual void __thiscall MyThread::run(void) " (?run@MyThread@@MAEXXZ)中被引用

在run函数中发射消息编译会报错....就不用写关联此信号的槽..了

　　　　一.2继承QObject并moveToThread

MyWork.h
------------------------------------
signals:
    void  signalsA();

MyWork.cpp
------------------------------------
void MyWork::slotsDoWork()
{
    ...
    emit signalsA();  
    ...
}

someWhere.cpp
-----------------------------------
QObject::connect(myWork, &MyWork::signalsA, this, &someWhere::slotsToDoSomething);

很顺畅，小熊目前没有发现什么问题。

情况二：依附线程发送消息，线程接收消息

暂未使用到，待补充