Detecting mouse motion

NOTE Override the MouseMoved member function when you want to take an action as the mouse is moved--such as updating the display to reflect the new position.

When you have finished with watching mouse motion, call the MMouseEventHandler::StopMouseMovedEvents method. Remember that Views can only get move events for events that occur within the bounds of the View or sub-View.

Detecting entry and exit to a view

• StartMouseEntryEvents--If the application is not already watching its associated Views then it will begin to detect mouse entries and exits.
• StopMouseEntryEvents--Call this method when you want to stop your application from receiving mouse entry or exit events. If the application is not receiving mouse entry events nothing happens when this method is called.
• MouseEntered--This method should be overridden if you want your application to take an action upon the mouse pointer entering the View.
• MouseExited--This method should be overridden if you want to take an action as the mouse pointer leaves the current View.

NOTE Do not depend on the coordinates returned by the methods for Enter and Exit events. The result is nondeterministic.

Views can only get entry and exit events for areas within the bounds of the View. A View can only "watch" itself or a sub-View. It cannot watch a sibling View.

TInteractor objects bypass this restriction--they can watch any view within their thread. Refer to Chapter 4, "View System concepts" for an explanation of Views, threads and TInteractor objects. Refer to "Interactors" on page 34 for an explanation of how the TInteractor mechanism works.

In general, you should structure your application to set the coordinate view to the View that your application wants to watch. Then call the StartMouseEntryEvents method and override the MouseEntered and MouseExited member functions to provide application-specific behavior.

NOTE If you are creating your own views, there is no need to add the mixin class MMouseEventHandler. This is done by the view class.