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-->  <!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"><concept id="GUID-7B275129-5EF7-4B27-B603-3BDE2C650A93" xml:lang="en"><title>Queries</title><prolog><metadata><keywords></keywords></metadata></prolog><conbody>
<p>A query is a state where the software waits for user input. Queries are
used in situations with more than one ways to proceed, when the application
needs data from the user, or when it is necessary to make sure the user knows
what is happening. A query must be exited before the application can proceed.</p>
<p>Queries are displayed in pop-up windows. The following query types can
be used:</p>
<ul>
<li><p><xref href="GUID-48482288-B60B-477A-8E28-132F7CBE2C94.dita">Confirmation
query</xref>: a question or notice with one or two possible responses. </p></li>
<li><p><xref href="GUID-13DEE42F-3EAB-4EB7-9CE1-C4930BCACE01.dita">List query</xref>:
a question with a selection of more than two possible (predefined) responses
in a list. </p></li>
<li><p><xref href="GUID-434F2412-59A1-4BCB-885D-5E708EAA6AB6.dita">Grid query</xref>:
a question with a selection of more than two possible (predefined) responses
in a grid. </p></li>
<li><p><xref href="GUID-DAD40CCE-EA59-4DCA-8922-824B18F0387A.dita">Multi-selection
list query</xref>: presents a list of items; the user can select any number
of them. </p></li>
<li><p><xref href="GUID-F77CC49A-904D-486B-8D16-972525EC34D5.dita">Data query</xref>:
used for numeric or textual input. </p></li>
<li><p><xref href="GUID-7235E4E9-0046-4BE1-91CF-BD52CE4489DF.dita">Message query</xref>:
used for various purposes in queries that are longer than one screen.</p></li>
</ul>
<section><title>Using queries in C++
applications</title><p>The APIs to use for queries are the Queries
API, Dialogs
API, and the Popups
API. For implementation information, see Using
the Dialogs API.</p><p>Query dialogs are dialogs that can be used to
require user input or user selection. All query dialogs derive from <xref href="jar:GUID-759FBC7F-5384-4487-8457-A8D4B76F6AA6.jar!/html/classCAknQueryDialog.html" format="application/java-archive"><codeph>CAknQueryDialog</codeph></xref>,
which inherits <xref href="jar:GUID-759FBC7F-5384-4487-8457-A8D4B76F6AA6.jar!/html/classCAknDialog.html" format="application/java-archive"><codeph>CAknDialog</codeph></xref>.
There are two types of queries: local and global queries. Local query dialogs
are local to a certain application. That means they are only displayed within
this application. Global query dialogs are system-wide queries, and are shown
topmost even when another application moves to the foreground. Query dialogs
require resource definitions when they are used in your code. </p><note><p>In
order to have a header pane, the <codeph>AVKON_HEADING</codeph> component
should be specified as the first dialog line in the resource description.</p></note><p>At
runtime, the dialog's header pane (<xref href="jar:GUID-759FBC7F-5384-4487-8457-A8D4B76F6AA6.jar!/html/classCAknPopupHeadingPane.html" format="application/java-archive"><codeph>CAknPopupHeadingPane</codeph></xref>) can be obtained by calling the method <xref href="jar:GUID-759FBC7F-5384-4487-8457-A8D4B76F6AA6.jar!/html/classCAknQueryDialog.html#8222b5679180543798d67db49abd4500" format="application/java-archive"><codeph>CAknQueryDialog::QueryHeading()</codeph></xref>.</p><p>The following
parts are available for modification from the class <xref href="jar:GUID-759FBC7F-5384-4487-8457-A8D4B76F6AA6.jar!/html/classCAknQueryDialog.html" format="application/java-archive"><codeph>CAknQueryDialog</codeph></xref>:</p><ul>
<li><p>Data query </p><ul>
<li><p>Header text </p></li>
<li><p>Header image/animation </p></li>
<li><p>Prompt text </p></li>
<li><p>Edit indicator (can be removed) </p></li>
</ul></li>
<li><p>Confirmation query </p><ul>
<li><p>Prompt text </p></li>
<li><p>Image/animation </p></li>
</ul></li>
<li><p>List query </p><ul>
<li><p>Header text </p></li>
<li><p>Header image/animation </p></li>
<li><p>List type (Single, SingleHeading, SingleGraphic, SingleGraphicHeading) </p></li>
</ul></li>
</ul><p>The following example illustrates the resource definition for the
Secret Editor Query, which contains a Secret Editor, resides inside the dialog.
The values for flags, type, id, and control are specific to the query dialog.
These values are enumerated in the file avkon.hrh, which is in the <codeph>./epoc32/include</codeph> folder.</p><codeblock xml:space="preserve">RESOURCE DIALOG r_aknexquery_code_query
    {
    flags = EGeneralQueryFlags
    buttons = R_AVKON_SOFTKEYS_OK_CANCEL;
    items =
        {
        DLG_LINE
            {
            type = EAknCtQuery;
            id = EGeneralQuery;
            control = EGeneralQueryFlags
                {
                layout = ECodeLayout;
                label = label_text;
                control = SECRETED
                    {
                    num_letters = 8;
                    };
                };
            }
        };
    }
</codeblock><p>The query in the above example includes a secret editor. For
information on implementing secret editors, see the Editors
API.  </p></section>
</conbody></concept>