Qt QThread兩種方式的使用：1-繼承QThread重寫run函數； 2- 繼承QObject並moveToThread && 消息和槽在線程和依附線程間的傳遞

2019年08月18日起筆

方式一：繼承QThread重寫run函數

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：繼承QObject並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分別在哪個線程中運行？ ：https://www.cnblogs.com/azbane/p/11465466.html
*/

消息和槽在線程和依附線程間的傳遞：

首先說明：依附線程是指創建線程的線程。

情況一：線程發射消息，依附線程接收消息

　　　　一.1繼承QThread重寫run函數，小熊嘗試失敗，針對代碼及編譯錯誤消息如下：

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

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

編譯錯誤：
---------------------------------
LNK2019：無法解析的外部符號＂public: void __thiscall MyThread::signalsA(void)＂（？signals@MyThread@@QAEXXZ），該符號在函數 " protected: virtual void __thiscall MyThread::run(void) " (?run@MyThread@@MAEXXZ)中被引用

在run函數中發射消息編譯會報錯....就不用寫關聯此信號的槽..了

　　　　一.2繼承QObject並moveToThread

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

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

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

很順暢，小熊目前沒有發現什么問題。

 

情況二：依附線程發送消息，線程接收消息

暫未使用到，待補充