Qt -how to know whether content in child widgets has been changed?

In QMainWindow I have 2 QSplitters. In that splitters I have QTextEdit, QLineEdits, QTableWinget, Ragio buttons and so on... I want to know if somthing has been chaged after pressing File->New menu button. Is there any general method for doing this?

Somwhere I have read that it is recomended to use isWindowModified() function of QMainW开发者_开发技巧indow, but seems it doesn't work.

setWindowModified() does not propagate the windowModified flag to the parents. This bug is described here: https://bugreports.qt.io/browse/QTBUG-20150. I have just tried it and indeed it did not work.

The isWindowModified() could be useful here since according to http://doc.trolltech.com/4.6/qwidget.html#windowModified-prop it propagates up to the parent.

However, I think you would need to set this yourself. For example, if you clicked the new button which leads to some text being inserted into a QTextEdit, you still need to call QTextEdit's setWindowModified() function - which will then propagate up to your QMainWindow - and you can just check QMainWindow afterwards. (However, you wouldn't know which children were modified)

Maybe you should have a look at QWidget::changeEvent.