Class: QgsApplicationExitBlockerInterface

class qgis.gui.QgsApplicationExitBlockerInterface

Bases: sip.wrapper

An interface that may be implemented to allow plugins or scripts to temporarily block the QGIS application from exiting.

This interface allows plugins to implement custom logic to determine whether it is safe for the application to exit, e.g. by checking whether the plugin or script has any unsaved changes which should be saved or discarded before allowing QGIS to exit.

QgsApplicationExitBlockerInterface are registered via the iface object:

class MyPluginExitBlocker(:py:class:`.QgsApplicationExitBlockerInterface`):

   def allowExit(self):
       if self.has_unsaved_changes():
           # show a warning prompt
           # ...
           # prevent QGIS application from exiting
           return False

       # allow QGIS application to exit
       return True

my_blocker = MyPluginExitBlocker()
iface.registerApplicationExitBlocker(my_blocker)

Methods

allowExit

Called whenever the QGIS application has been asked to exit by a user.

allowExit(self) → bool

Called whenever the QGIS application has been asked to exit by a user.

The subclass can use this method to implement custom logic handling whether it is safe for the application to exit, e.g. by checking whether the plugin or script has any unsaved changes which should be saved or discarded before allowing QGIS to exit.

The implementation should return True if it is safe for QGIS to exit, or False if it wishes to prevent the application from exiting.

Note

It is safe to use GUI widgets in implementations of this function, including message boxes or custom dialogs with event loops.

Return type

bool