Qt应用程序界面冻结

Question

I'm experiencing some problems with my embedded application. It is a page that contains a QTimeEdit that counts the time each second, some checkboxes and some QLineEdit s that refresh each second.

After some minutes of working, I see a freeze of interface, even if the application is still running. If a try to press buttons or checkboxes an access violation message appears:

Exception 'Access Violation' (14): Thread-Id=05d80002(pth=8af6109c), Proc-Id=04a90002(pprc=91431714) 'nmb3.exe', VM-active=04a90002(pprc=91431714) 'nmb3.exe' PC=407ea307(qtgui4.dll+0x0005a307) RA=40d6c82c(qtgui4.dll+0x005dc82c) SP=01c1b928, BVA=00000004

The exception is related to qtgui4.dll . I checked if a saturation of virtual memory occurs, but this is not the problem that causes the freeze.

The freeze doesn't occur if I avoid to update the QTimeEdit , but I don't understand why.

Answer 1

You should move the timer into the mainwindow class, keeping the sensors handler in the separated thread.

The sensors handler should:

• store the data
• emit a "data ready" signal to the window

Then the timer in the mainwindow, every second, will:

• read the data from the sensors handler
• update the GUI

(make sure you are using thread-safe objects or, managing the critical sections)