sending message to the client using Qt

[JonB]

@fari35
You won't "make an object of fserver class in fthread class". Just connect a signal out of the UI on button press to the slot in the thread to send the message to the client. As I wrote earlier, you'll have to do the connect() for each thread-client.

Do not explicitly write the Qt::DirectConnections I see you have. Leave Qt to determine connection types (omit the parameter). When connecting across threads it will use Qt::QueuedConnection, which is what is required.

Don't try to specify a &MainWindow::sendmessage in any non-MainWindow class. Make connections in a class which knows about both the sending-thread instance and receiving-thread instance. If necessary, declare your own signal not in MainWindow class but rather in server thread class. It is permissible for a class to emit a signal which is declared in another class.

[fari35]

@JonB I am trying to connect the signal in mainwindow with the slot in fthread like this:

connect(mainobj, &MainWindow::sendmessage,this, &fthread::sendmessage);

but I am not able to make the mainwindow object in fthread class. Is there any alternate way of doing this?

[JonB]

@fari35
I just answered that in my final paragraph above.

fthread knows nothing about either MainWindow or mainobj. One solution is to do this connection in the MainWindow instance, where main window knows about each fthread instance. Another solution is to define the signal in fthread class and have main window go emit fthreadIntance->fthreadSignal().

[fari35]

@JonB I am sending the message to client like this :

  thread_obj->tcpSocket->write(block);

from the send_onclicked method in main window but as soon as I click on the send button the program is crsahing

[JonB]

@fari35
You are invoking the thread method directly from another thread. Don't do that. As I said, emit a signal, which Qt will connect with QueuedConnection because it is across threads.

[fari35]

This post is deleted!

[fari35]

@JonB But still if I'm emmiting a signal from mainwindow I need to connect the signal in mainwindow to the slot in fthread and for that I need a mainwindow class instance, so how can I do that. I cannot connect them in mainwindow class.

[JonB]

@fari35 said in sending message to the client using Qt:

I cannot connect them in mainwindow class.

That is indeed where you should do the connection! It should connect the button press to a slot in each thread you create.

I never allow #include "mainwindow.h" in any file other than mainwindow.cpp. Other modules should know nothing about a main window, whether it exists or not.

Have the thread class export a slot. Include that into mainwindow.cpp. When a thread instance is created, have main window connect() its button signal to the thread slot, for each thread. (You can also create a custom signal wrapper if it's neater.) If necessary, have the thread emit a signal when it is created so that the main window knows to do the connection.

In a word, the main window can know about threads, but the threads should not know about the main window. Therefore the connect()s should not be in the threads but rather in the main window.

[fari35]

@JonB I have done this but now When I emit a signal sendmessage() from mainwindow class (sendmessage() signal is working perfectly fine) to the slot of thread class so the thread class does not emit the gotnewmessage() signal when I want to send the data to mainwindow class that it needs to show in text box. Do you hav any idea why is that happening?

[ghostkitchen]

This post is deleted!