When the user clicks it again (to uncheck it), the button moves first to the pressed state, then to the unchecked state ( isChecked() and isDown() are both false). When the user clicks a toggle button to check it, the button is first pressed then released into the checked state.
The difference between isDown() and isChecked() is as follows.
setCheckable() sets whether the button is a toggle button or not.autoRepeatDelay and autoRepeatInterval define how auto-repetition is done. setAutoRepeat() sets whether the button will auto-repeat if the user holds it down.Note: As opposed to other widgets, buttons derived from QAbstractButton accept mouse and context menu events when disabled.
