Interpretation of QT keypressevent

Qt KeyPressEvent Function introduction ：

KeyPressEvent Is a key press event handler ;
To get a key press event , This part must call setFoucusPolicy（） function , Initialize focus , And getting the focus .
When you reload KeyPressEvent Function time , If you don't operate the keys , You need to call the overloaded function of the base class .
default KeyPressEvent function , The user presses the cancel key （ Typical is ESC Key ）, Close the ejected part . Other keys will be ignored , Refer to parent components for processing .

Particular attention ：
QKeyEvent The first thing that came in was IsAccepted（） 了 , You don't have to call QKeyEvent::accept() Set the event status attribute ; If you want to operate the keys , You just don't call the overloaded functions of the base class ;

setFoucusPolicy Reading

Set how the part accepts the key value of the keyboard focus .
Particular attention ： The default method is Qt::NoFocus, Do not deal with focus .

KeyPressEvent Use