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<concept id="GUID-B57ECD51-85EF-50EA-B3EE-62A85CD9C382" xml:lang="en"><title>How

to use a notifier to display a simple dialog, asynchronously</title><shortdesc>Provides code snippets to show you how to use a notifier to display

a simple dialog asynchronously.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>To display a simple dialog box:</p>

<ul>

<li id="GUID-9BB8982B-727E-57FB-951F-EEA8CA49D203"><p>construct an <codeph>RNotifier</codeph> object

and then call its <codeph>Connect()</codeph> member function to create a session

with the Notifier server.</p> </li>

<li id="GUID-F6523ED3-4816-538B-86BB-576A05E47197"><p>call the <codeph>Notify()</codeph> member

function of the <codeph>RNotifier</codeph>, passing descriptors containing

the two lines of text to be displayed and the characters for the buttons. <codeph>Notify()</codeph> makes

an asynchronous request to the notifier server.</p> </li>

</ul>

<p>When the user keys in one of the button characters, the requesting thread's <keyword>request

semaphore</keyword> is signalled to indicate that the notifier request is

complete. The <codeph>TRequestStatus</codeph> object supplied by the requesting

thread is set to <codeph>KErrNone</codeph>.</p>

<p>In addition, a <codeph>TInt</codeph>, passed by reference to <codeph>Notify()</codeph>,

is set to 0 or 1 depending on whether the first or the second button is selected.</p>

<p>The session is closed by calling the <codeph>Close()</codeph> member function

of the <codeph>RNotifier</codeph>.</p>

<p>The following code fragments demonstrate this:</p>

<codeblock id="GUID-8FDAA342-A5C9-5D27-B3DE-8F62124BADA4" xml:space="preserve">{

_LIT(KTxtLine1,"First line");

_LIT(KTxtLine2,"Second line");

_LIT(KButt1,"a");

_LIT(KButt2,"b");

...

TInt           whichbutton(-1);

TRequestStatus stat;

...

RNotifier      notifier;

...

notifier.Connect();

...

notifier.Notify(KTxtLine1,KTxtLine2,KButt1,KButt2,whichbutton,stat);

...

// other code

...

User::WaitForRequest(stat);

...

if (whichbutton==0)

    {

    // first button selected

    }

if (whichbutton==1)

    {

    // Second button selected

    }

...

notifier.Close();

...

}</codeblock>

<p>Note that the descriptor parameters passed to <codeph>Notify()</codeph> must

remain in existence until the notify request completes; this may be some time

after the call to <codeph>Notify()</codeph> itself.</p>

</conbody></concept>