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<concept id="GUID-E402616A-7ED8-45AC-B836-99C3A3760B33" xml:lang="en"><title>Key events</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<fig id="GUID-9A1FDF4B-5FD8-4113-8D8E-E879B4C7C255"><title>Key presses generate key events</title><image href="GUID-C9429505-EEE7-4E64-BE0A-BC5D57D5B42C_d0e39244_href.png"/></fig>

<p>Key events are generated when a mobile device user presses one or more

mobile device key buttons. The application framework delivers the event to

the application that has focus. The <parmname>TKeyEvent</parmname> structure

is used to contain the key event details delivered to the application. For

more information on <parmname>TKeyEvent</parmname>, see <xref href="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/reference/reference-cpp/Window_Server/TKeyEventStruct.html" format="application/java-archive"><parmname>TKeyEvent</parmname></xref>. </p>

<p>The structure is as follows:</p>

<codeblock id="GUID-467AB9BB-948F-49B6-A243-206314E90242" xml:space="preserve">struct TKeyEvent

    {

    TUint iCode;

    TInt iScanCode;

    TUint iModifiers; // State of modifier keys

    TInt iRepeats; // Count of auto repeats generated

    };

</codeblock>

<p>The following events are generated by means of a single key press and

release:</p>

<codeblock id="GUID-5FE1F179-8F7A-4653-9604-3CFC4B66AE33" xml:space="preserve">EEventKeyDown

EEventKey

EEventKeyUp

</codeblock>

<p>The first event indicates that a key has been pressed down. The second

event indicates that a character has been received from the keyboard. The

third event is sent when the button has been released. These events are described

in the <parmname>iCode</parmname> and <parmname>iSCanCode</parmname> members

of <parmname>TKeyEvent</parmname>.</p>

<p>For more information on possible data contained in <parmname>EEventKey</parmname>,

see <xref href="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/reference/reference-cpp/Kernel_Architecture_2/e32keys.hGlobals.html#%3a%3aTKeyCode" format="application/java-archive"><parmname>TKeyCode</parmname></xref>.</p>

<p>Key presses may be interpreted by a Front End Processor (FEP) and tied

to specific key events. For example, if a mobile device user presses the <parmname>2</parmname> key

twice, an active FEP could generate a key event code of <parmname>b</parmname>.</p>

<p> For more information on FEPs, see <xref href="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/guide/Application-Framework-subsystem-guide/fepbase/FrontEndProcessorOverview.guide.html#ApplicationFrameworkOverview%2eFrontEndProcessorOverview%2emain" format="application/java-archive">Front End Processor overview</xref>.</p>

</conbody></concept>