QT realizes signal transmission and reception between two windows

It mainly uses the correlation implementation method of signal and slot

1、 Implementation process

1、 Create a new one Widget, And then build another one QMainWindow.
2、 stay mainwindow.h Custom signal in header file , Use it when declaring signals keyword , stay public、private and protect And so on , Because the signal defaults to public function .

3、 stay mianwindow.ui Add spinbox And a button.
4、 Then go to pushbutton The slot corresponding to the stand-alone signal of , Add the function code as follows ：

So click the button to get spinBox The value in , And send the obtained value . It is actually sent to memory , Wait for the slot function to get .
5、 stay widget.h Add a custom slot declaration in the header file ：

6、 And then in widget.ui Drag in a Lable, Used to receive the previously sent value .

7、 I'll see you next widget.cpp The implementation of custom slots in the source file , Is to capture the signal transmitted in front , Display values in lable in .

8、 The next in widget.cpp Associate the signal with the slot in the source file .

2、 Running effect