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<concept id="GUID-31A28040-6C8E-5C65-A697-04B30B441686" xml:lang="en"><title>FEP
References</title><shortdesc>This topic introduces miscellaneous guidelines to write a FEP.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<section id="GUID-7881D352-F261-4064-8684-6CA76A184257"><title> Handling the
start of a transaction</title><p>Although applications do not need to be FEP-aware
in order to work with FEPs, a situation can occur in some applications in
which the user interface can be improved by the application making use of
a FEPBASE API to communicate with the FEP above it, if there is one. </p> <p>If
no FEP is present, the expected behaviour in some UIs when the user presses
a key is for the application to do two things: firstly, it moves focus to
a previously non-focused text editor control (possibly, although not necessarily,
by launching a dialog), and secondly, it 'seeds' that text editor control
with the character associated with that key. If there is a FEP, by default
(in other words, without the application being FEP-aware) the focus change
would only happen when the FEP outputs text to the application. However, if
the FEP is designed to allow the user to compose a fairly large block of text
to send to the application (as would be likely in a Japanese FEP), it would
be better if the focus change occurred when the user starts composing their
text in the FEP. In order for this to happen, the application needs to be
FEP-aware, albeit in a fairly trivial way. The way the FEP notifies the application
that it is starting a transaction is by calling <codeph>CCoeEnv</codeph> ’s
member function <codeph>ForEachFepObserverCall()</codeph> (<codeph>CCoeEnv</codeph> is
defined in <filepath>epoc32\include\COEMAIN.H</filepath>), passing in the
address of the non-member function <codeph>FepObserverHandleStartOfTransactionL()</codeph> (defined
in <filepath>epoc32\include\FEPBASE.H</filepath>). It is important to note
that this function should only be called as the last C++ statement executed
when handling an event. The reason for this that it may take a considerable
amount of time to return (for example, it may launch a dialog and only return
when the dialog has been exited). </p> </section>
<section id="GUID-C32902E0-39A8-493E-9E7F-D48DEE4717CA"><title>Text cursors</title><p>If
a non-inline-editing FEP has a composition window into which the user types,
that window should not use a 'real' text cursor (in other words, a cursor
which is set and unset using <codeph>RWindowGroup</codeph> ’s <codeph>SetTextCursor()</codeph> and <codeph>CancelTextCursor()</codeph> member
functions). The reason is that the window server only allows a single text
cursor for the whole system at any one time. If the FEP’s target control is
a text editor, it should use the window server’s text cursor itself, so the
FEP should not use it. To solve this problem, the text cursor in the FEP’s
composition window can be simulated with a sprite. The class <codeph>CTstInsertionPoint</codeph> in
TFEP1 provides an example of this. </p></section>
<section id="GUID-5F7D9BFA-F74A-47FE-B589-A4EF49AFB901"><title>Shortcut keys</title><p>As
FEPs get first refusal of all key events, there is a risk that FEPs can intercept
shortcut keys (if the UI supports them) which are intended for the application
to handle. To define a convention for FEP shortcut keys is non-trivial as
different UIs use different modifier keys and have different policies on using
them. Matters are simplified greatly if a product has a dedicated on/off key
for FEPs as this may be used in combination with other keys to carry out different
functions, as well as on its own to turn the FEP on and off. FEP authors should
consult the documentation for their target UI. </p></section>
</conbody></concept>