Slide 6.17: Line-by-line anatomy of Hello.c
Slide 6.19: Line-by-line anatomy of Hello.c (cont.)
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Slide 6.17: Line-by-line anatomy of Hello.c Slide 6.19: Line-by-line anatomy of Hello.c (cont.) Home |
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Hello.c (Cont.)
EventType event;
typedef struct {
eventsEnum eType;
Boolean penDown;
UInt8 tapCount;
Int16 screenX;
Int16 screenY;
union {
...
} data;
} EventType;
where the fields are
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The struct EventType contains all the data associated with a system event.
All event types have some common data.
Most events also have data specific to those events.
The specific data uses a union that is part of the EventType data structure.
The Event Reference section gives details on the important data associated with each type of event.
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true if the pen was down at the time of the event, otherwise false.
When the handheld is in doze mode, an interrupt is generated when the pen is first brought down on the screen.
After a pen down is detected, the system software polls the pen location periodically (every 20 ms) until the pen is again raised.
Most applications never need to call the Pen Manager directly because any pen activity is automatically returned to the application in the form of events.