c++ - 解构对象给出 QCoreApplication::sendEvent:“无法将事件发送到不同线程拥有的对象

Question

我的代码太长了，这里是相关部分:

videoClass::videoClass()
{   
    ...
    QThread* workerThread = new QThread(this);
    camwrk = new cameraWorker(workerThread);
    camwrk->moveToThread(workerThread);
    // There are many cross thread signal slot connections happening between this and the camwrk
}

videoClass::~videoClass()
{   
    ...

    delete camwrk;
    ...
}

cameraWorker::cameraWorker(QThread* workerThread)
{
    _belongingThread = workerThread;
    ...
}

cameraWorker::cameraWorker(QThread* workerThread)
{
    _belongingThread = workerThread;
    ...
}

cameraWorker::~cameraWorker()
{
    _belongingThread->quit();
    _belongingThread->wait();
}

每次当 _belongingThread->wait();完成后，我收到消息:

QCoreApplication::sendEvent: "Cannot send events to objects owned by a different thread

这里发生了什么？我认为这是使用 QThread 并完成它的正确方法吗？

Answer 1

QThread对象本身属于主线程:

It is important to remember that a QThread instance lives in the old thread that instantiated it, not in the new thread that calls run().

显然，QThread::wait() 是通过事件实现的。由于 cameraWorker 本身在 workerThread 上运行，而不是在 videoClass 的线程上运行，因此您不能使用它。

话虽如此，您当前的逻辑似乎有点太复杂了。你想在 cameraWorker 被销毁时停止线程，并且你想在它的父级也被销毁时销毁 camera worker:

QThread* workerThread = new QThread(this);

connect(camwrk, SIGNAL(destroyed()), workerThread, SLOT(quit()));
connect(this,   SIGNAL(destroyed()), camwrk,       SLOT(deleteLater()));

如果您想在 workerThread 完成执行后删除它，只需连接 finished() 和 deleteLater():

connect(workerThread, SIGNAL(finished()),
        workerThread, SLOT(deleteLater()));

但是，请记住 ~videoClass() 将调用 workerThread 的析构函数。确保线程在对象被销毁之前不再运行，或者简单地从 new QThread(this) 中删除 this 以防止所有权。