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Chapter 17: Trigger Control
Virtual Key Codes
Psion Mobile Devices Developers Guide
180
17.4.1 Virtual Key Codes
See the following for a list of virtual key codes:
C++: PsionTeklogix::Keyboard::Key enumeration
Java: com.teklogix.keyboard.VirtualKey class
.NET: PsionTeklogix.Keyboard.Key enumeration
17.5 Trigger Associations
In order to receive trigger events, a trigger consumer must be associated with one or more trigger sources.
Some hardware components should not be operated simultaneously, due to their heavy power consump-
tion. For example, an internal imager and a tethered RFID reader should not be scanning at the same time.
Doing so may cause the terminal to spontaneously turn off due to insufficient power.
Before being associated with the trigger source, the trigger consumer must register to receive trigger
events. Only the trigger consumers associated with a specific trigger source receive events originating with
that trigger. Several consumers can be associated with the same trigger source.
When a trigger consumer is deregistered, all its trigger associations are deactivated. If the trigger
consumer re-registers the associations are re-activated.
Each development language provides API elements that associate a trigger source ID with a
trigger consumer.
17.5.1 Trigger Control Flags
Trigger control flags modify a trigger association. These flags are specified when a trigger association is
created. Several trigger control flags can be set during one trigger association attempt.
Unless the temporary flag is set, all trigger associations are permanent and persist across both warm
resets and cold resets. It is recommended that unless the application is launched at system startup, the
temporary flag be set for all trigger associations.
Exclusive flag: Setting this flag ensures that only one trigger consumer is associated with a trigger source.
If this flag is set during an attempt to create a trigger association, the following can occur:
If there is no existing trigger association for the trigger source, the association is successful and all
further attempts to create an association for this trigger source fail until this exclusive association
is deleted.
If there is an existing trigger association for the trigger source, this attempt to create an exclusive
association fails.
Override flag: When this flag is set during an attempt to create a trigger association, all existing trigger
associations for the trigger source are replaced by the new one. Even an exclusive trigger association
is replaced.
Temporary flag: When this flag is set, the trigger association does not persist across either a warm reset or
a cold reset. If the override flag is also set, then the previous trigger association for the trigger source is
restored when this association is deleted, or the trigger consumer is deregistered. Only one
temporary-plus-override flag can be in existence for each trigger source.
Ignore duplicate registration flag: When this flag is set during a trigger association attempt, if the trigger
association already exists, no error is returned.
Wants-trigger-events flag: When this flag is set, the consumer receives trigger-down events and
trigger-up events. It does not receive double-click events unless the wants-double-click-events flag is also
set, or there are no consumers registered to receive double-click events.
Wants-double-click-events flag: When this flag is set, the consumer receives double-click events. To
receive single-click events too, the wants-trigger-events flag must also be set.
17.6 Double-Clicks
A double-click occurs when the pistol grip trigger or another trigger source is pressed twice within a very
short time. This time-gap is measured in milliseconds. The double-click time is the maximum time allowed
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