|
|
|
|
|
|
|
Now, finally, you need to add just one more, crucial message: the message
that tells the graph pane what to do when it is time to draw information on
the graph pane. In particular, you need to add a message that tells the
graph pane to send a message to the view manager that causes information in
the graph pane to be displayed. For example, you might choose to tell the
graph pane to send the callDrawMeter: message (at first
callDrawMeter will do the drawing itself; later, in
Segment••missing reference••, callDrawMeter is defined to call upon
another method, drawMeter, that does the drawing).
MeterPane instance CalorieViewManager instance (a graph pane) (a view manager) *----------* *----------* | | callDrawMeter: message | | | | ------------------------> | | | | | | *----------* *----------*