Symbian3/SDK/Source/GUID-31A28040-6C8E-5C65-A697-04B30B441686-GENID-1-8-1-3-1-1-9-1-4-1-11-1.dita
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     1 <?xml version="1.0" encoding="utf-8"?>
       
     2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
       
     3 <!-- This component and the accompanying materials are made available under the terms of the License 
       
     4 "Eclipse Public License v1.0" which accompanies this distribution, 
       
     5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
       
     6 <!-- Initial Contributors:
       
     7     Nokia Corporation - initial contribution.
       
     8 Contributors: 
       
     9 -->
       
    10 <!DOCTYPE concept
       
    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
       
    12 <concept id="GUID-31A28040-6C8E-5C65-A697-04B30B441686-GENID-1-8-1-3-1-1-9-1-4-1-11-1" xml:lang="en"><title>FEP
       
    13 References</title><shortdesc>This topic introduces miscellaneous guidelines to write a FEP.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
       
    14 <section id="GUID-7881D352-F261-4064-8684-6CA76A184257-GENID-1-8-1-3-1-1-9-1-4-1-11-1-3-1"><title> Handling the
       
    15 start of a transaction</title><p>Although applications do not need to be FEP-aware
       
    16 in order to work with FEPs, a situation can occur in some applications in
       
    17 which the user interface can be improved by the application making use of
       
    18 a FEPBASE API to communicate with the FEP above it, if there is one. </p> <p>If
       
    19 no FEP is present, the expected behaviour in some UIs when the user presses
       
    20 a key is for the application to do two things: firstly, it moves focus to
       
    21 a previously non-focused text editor control (possibly, although not necessarily,
       
    22 by launching a dialog), and secondly, it 'seeds' that text editor control
       
    23 with the character associated with that key. If there is a FEP, by default
       
    24 (in other words, without the application being FEP-aware) the focus change
       
    25 would only happen when the FEP outputs text to the application. However, if
       
    26 the FEP is designed to allow the user to compose a fairly large block of text
       
    27 to send to the application (as would be likely in a Japanese FEP), it would
       
    28 be better if the focus change occurred when the user starts composing their
       
    29 text in the FEP. In order for this to happen, the application needs to be
       
    30 FEP-aware, albeit in a fairly trivial way. The way the FEP notifies the application
       
    31 that it is starting a transaction is by calling <codeph>CCoeEnv</codeph> ’s
       
    32 member function <codeph>ForEachFepObserverCall()</codeph> (<codeph>CCoeEnv</codeph> is
       
    33 defined in <filepath>epoc32\include\COEMAIN.H</filepath>), passing in the
       
    34 address of the non-member function <codeph>FepObserverHandleStartOfTransactionL()</codeph> (defined
       
    35 in <filepath>epoc32\include\FEPBASE.H</filepath>). It is important to note
       
    36 that this function should only be called as the last C++ statement executed
       
    37 when handling an event. The reason for this that it may take a considerable
       
    38 amount of time to return (for example, it may launch a dialog and only return
       
    39 when the dialog has been exited). </p> </section>
       
    40 <section id="GUID-C32902E0-39A8-493E-9E7F-D48DEE4717CA-GENID-1-8-1-3-1-1-9-1-4-1-11-1-3-2"><title>Text cursors</title><p>If
       
    41 a non-inline-editing FEP has a composition window into which the user types,
       
    42 that window should not use a 'real' text cursor (in other words, a cursor
       
    43 which is set and unset using <codeph>RWindowGroup</codeph> ’s <codeph>SetTextCursor()</codeph> and <codeph>CancelTextCursor()</codeph> member
       
    44 functions). The reason is that the window server only allows a single text
       
    45 cursor for the whole system at any one time. If the FEP’s target control is
       
    46 a text editor, it should use the window server’s text cursor itself, so the
       
    47 FEP should not use it. To solve this problem, the text cursor in the FEP’s
       
    48 composition window can be simulated with a sprite. The class <codeph>CTstInsertionPoint</codeph> in
       
    49 TFEP1 provides an example of this. </p></section>
       
    50 <section id="GUID-5F7D9BFA-F74A-47FE-B589-A4EF49AFB901-GENID-1-8-1-3-1-1-9-1-4-1-11-1-3-3"><title>Shortcut keys</title><p>As
       
    51 FEPs get first refusal of all key events, there is a risk that FEPs can intercept
       
    52 shortcut keys (if the UI supports them) which are intended for the application
       
    53 to handle. To define a convention for FEP shortcut keys is non-trivial as
       
    54 different UIs use different modifier keys and have different policies on using
       
    55 them. Matters are simplified greatly if a product has a dedicated on/off key
       
    56 for FEPs as this may be used in combination with other keys to carry out different
       
    57 functions, as well as on its own to turn the FEP on and off. FEP authors should
       
    58 consult the documentation for their target UI. </p></section>
       
    59 </conbody></concept>