在主线程之外创建 QDialog 的方法
我正在尝试在 QT 中创建一个客户端应用程序，它需要两个线程进行处理和可变数量的窗口实例。但我很难弄清楚如何在处理线程之一内创建一个新窗口。我知道所有 ui 元素必须在与 QApplication 类相同的线程中创建，但我需要能够实例化，或者至少在另一个线程中引用 QDialog。
线程和 QDialog 之间的通信可以使用信号来完成，我并不担心这一点，但实际创建窗口是另一回事。我可以使用信号告诉主线程创建窗口的实例，然后以某种方式检索指向它的指针，但对我来说，这似乎有点复杂和丑陋。有没有更好的方法来完成这样的任务？要在主线程之外创建 QDialog QApplication 类是否存在？
编辑：我尝试过 Q_INVOKABLE 方法，但它不能跨线程工作。我创建了一个视图工厂类，它可以创建我指定类型的 QDialog 并返回指向它的指针。此类已在主 GUI 线程中实例化，并且对该类的引用将发送到任何工作线程。问题是，当线程使用 Qt::BlockingQueuedConnection 从工厂调用 create 方法时，调用方法会失败。如果我将其更改为 Qt::DirectConnection，则调用方法将调用正确的创建方法，但在当前线程中作为工作线程。
我的主要函数如下所示：
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
ViewFactory vFactory;
vFactory.registerCreator(Util::W_CONNECT, new ConnectWindow::ConnectCreator());
ClientApp app;
if(!app.Initialize(&vFactory))
return 0;
app.start();
a.exec();
.............................
}
我的 ClientApp 线程的运行函数如下所示：
void ClientApp::run()
{
QDialog * tmp = NULL;
QMetaObject::invokeMethod(this->_vFactory, "create", Qt::BlockingQueuedConnection,
Q_RETURN_ARG(QDialog*, tmp), Q_ARG(int, 0));
}
就像我说的，如果我将连接类型更改为 Qt::DirectConnection，invokeMothod 不会失败，所以参数不是问题，但是而是通过单独的工作线程调用该方法。
I am trying to create a client application in QT which requires both threads for processing and a variable amount of window instances. But I am having a hard time trying to figure out how to create a new window inside one of the processing thread. I understand that all ui elements must be created in the same thread as the QApplication class, but I need to be able to instantiate, or at least have a reference to a QDialog in another thread.
Communicating between the thread and QDialog can be done using signals, I am not worried about this, but actually creating the window is another matter. I could use signals to tell the main thread to create an instance to the window, and then retrieve the pointer to it somehow, but to me that seems a bit to complicated and ugly. Is there a better way to accomplish such a task? To create a QDialog outside the main thread were the QApplication class exists?
Edit : I have tried the Q_INVOKABLE method but it does not work across threads. I have created a view factory class which can create a QDialog of a type I specify and returns a pointer to it. This class has been instantiated in the main GUI thread and a reference to this class is sent to any worker threads. The problem is that, when a thread invokes the create method from the factory using Qt::BlockingQueuedConnection, the invoke method fails. If I change it to Qt::DirectConnection, the invoke method calls the right create method but in the current thread as the worker thread.
My main function looks like this :
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
ViewFactory vFactory;
vFactory.registerCreator(Util::W_CONNECT, new ConnectWindow::ConnectCreator());
ClientApp app;
if(!app.Initialize(&vFactory))
return 0;
app.start();
a.exec();
.............................
}
And my run function from the ClientApp thread looks something like this :
void ClientApp::run()
{
QDialog * tmp = NULL;
QMetaObject::invokeMethod(this->_vFactory, "create", Qt::BlockingQueuedConnection,
Q_RETURN_ARG(QDialog*, tmp), Q_ARG(int, 0));
}
Like I said, the invokeMothod will not fail if I change the connection type to Qt::DirectConnection, so the params are not the problem, but rather calling the method across a separate worker thread.
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你只能在 gui 线程中做 Gui 的事情。显而易见的解决方案是工作线程向 gui 线程发送消息 = Qt 术语中的信号。
如果工作线程需要提出问题，它应该向 gui 线程发送一条消息，然后阻塞，直到收到返回信号。
You can only do Gui stuff in the gui thread. The obvious solution is for the worker thread to send a message to the gui thread = a signal in Qt terms.
If a worker thread needs to ask a question it should send a message to the gui thread and then block until it gets a signal back.
AFAIK，信号（或者只是一个动态可调用方法，使用
Q_INVOKABLE）或事件是可行的方法。请注意，使用
QMetaObject::invokeMethod()< /a> （带有Qt::BlockedConnection），您可以跨线程安全地调用函数并获取返回值，而无需太多编码。AFAIK, signals (or just a dynamically callable method, using
Q_INVOKABLE) or an event is the way to go.Note that, using
QMetaObject::invokeMethod()(withQt::BlockedConnection), you can call a function safely across threads and get a return value back without too much coding.看起来
QObject::moveToThread可以解决这个问题。该函数将事件处理循环移动到另一个线程。Qt 文档中的示例：
It seems like
QObject::moveToThreadcan solve this problem. This function moves event processing loop to another thread.Example from Qt documentation: