Detecting virtual keyboard open and close events in Symbian^3

Comments

treinio 13:53, 19 April 2011 (UTC): Seems to work with Swype as well on N8.

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Bad idea ...

The pskeydefs.qcrml file would have to be installed in an hardcoded location, therefore only one application can place it there. A second application attempting to copy a new copy at the same location would fail to install.

The only way this would work is if the file is provided by the mobility package itself...

ltomuta 23:54, 7 June 2011 (EEST)

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treinio 15:53, 10 June 2011 (EEST): Good point Lucian. I modified the article so that it modifies the deployed .qcrml filename to be unique. It doesn't address the issue of multiple applications installing identical value space path(s), but according to my tests it causes no problems.

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treinio 16:33, 10 June 2011 (EEST): Also, if having a .qcrml file is something that application wants to avoid at all costs, check the history of the article, there is a native symbian implementation that requires no additional files to be deployed.

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Article Metadata

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Code Example

Source file: Media:Vkbstatetest qtmobility symbian3.zip

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Article

Created: treinio (09 Dec 2010)

Last edited: hamishwillee (11 Oct 2012)

Applications running on Symbian touch devices may want to react to software input panel (virtual keyboard) state events; for example, to improve user experience by immediately processing the input after virtual keyboard is dismissed. Qt provides QEvent::CloseSoftwareInputPanel event, but it's sent only after the target widget has lost focus.

This code snippet uses QValueSpaceSubscriber to detect virtual keyboard state changes. The code depends on a Publish and Subscribe key that is only available on Symbian^3 platform.

Warning: The following code implements a Qt class whose functionality is neither cross-platform nor future-proof. It only works on Symbian^3 platform with the default virtual keyboard in use (no signals are emitted when running on earlier S60 devices or other platforms).

Usage

#include <QValueSpaceSubscriber> 
 
    QValueSpaceSubscriber* vkbState = new QValueSpaceSubscriber("/vkb/state", this);
    QObject::connect(vkbState, SIGNAL(contentsChanged()), this, SLOT(handleStateChanged()));

Declaring /vkb/state value state path

Create a new .qcrml file, with following content:

<?xml version="1.0" encoding="UTF-8"?>
<repository target="RProperty" version="" uidName="KPSUidAknFep" uidValue="0x100056de">
    <key ref="/vkb/state" int="0x00000004"/>
</repository>

Changes to .pro file

Add the following definitions to .pro file:

CONFIG += mobility
MOBILITY += publishsubscribe
 
symbian: {
crml.pkg_postrules = "\"pskeydefs.qcrml\" - \"c:/resource/qt/crml/pskeydefs_$${TARGET}.qcrml\""
DEPLOYMENT += crml
}

Warning: While this article shows how the Publish and Subscribe API can be used to access keys defined and populated by other applications, creating such a *.qcrml file raises the deployment problem. In Symbian each file can be owned and deployed by only one package, so if two applications are using this solution and attempt to install the pskeydefs.qcrml file, the second app will always fail. The uninstall sequence is also problematic, since one of the apps could remove the file while other installed apps still need it.

Above solution tries to avoid these problems by modifying the deployed .qcrml filename to include also the name of the application (TARGET), thus making it unique.

Example project

File:Vkbstatetest qtmobility symbian3.zip (can be self-signed, doesn't use any capabilities)