If the button has a frame, change its
features by setting new frame IDs using the method SetFrameAndCenterIds() in the class CAknButton.
Use the flag KAknButtonStateHasLatchedFrame for
a button state to set whether the frame for the button in the state
in question should look latched down.
To disable the frame
for the button, use the KAknButtonNoFrame flag.
By default, the button text is truncated to fit the
size of the button. Use the KAknButtonSizeFitText flag to make the method MinimumSize() return the
size into which the text fits. To change the font, color, and alignment
of the text, use the following methods in CAknButton:
SetTextFont()
SetTextColorIds()
SetTextHorizontalAlignment()
SetTextVerticalAlignment()
If you use an icon in your button, you can use the same icon for both the pressed and non-pressed states; however, for the dimmed state another icon is recommended. For the icon's appearance, follow the Symbian look and feel guidelines. Dimmed icons are generated automatically if they are not provided by the application.
To
change the scale mode for the icon image, use the method CAnkButton::SetIconScaleMode(). By default, the button
component uses the EAspectRatioNotPreserved mode,
so that the icon fits the size of the button. To adjust the icon’s
alignment on the button, use the methods CAknButton::SetIconHorizontalAlignment() and CAknButton::SetIconVerticalAlignment().
If the button provides a help text, it is shown
close to the button if the button is focused or the stylus is held
down for some time. You can set the state-specific help text when
constructing the button, at the construction of a button state, or
by calling CAknButtonState::SetHelpTextL(). To
set the help text for a dimmed button, use the method CAknButton::SetDimmedHelpTextL().
To change time-outs for the help text, use the method CAknButton::SetHelpNoteTimeouts().
To display and
hide the button help text, use the methods ShowHelpL() and HideHelp() in the class CAknButton.
CAknButton supports a background
composed of both a CCoeControl background interface
and an Avkon skin background. If both are set, the CCoeControl-based background has higher priority. In case of CCoeControl-based background, do the following in order for the button’s background
to be drawn by the container:
Set the container class to be derived from the MCoeControlBackground interface.
Provide implementation for the Draw() method
in the MCoeControlBackground interface.
Call the SetBackground( pointerToContainer ) method for the button.
If the background is set from the skin, use the method CAknButton::SetBackGroundIds().
For implementation examples, see the sample code below:
// Text alignment top-left corner CGraphicsContext::TTextAlign horAlignment( CGraphicsContext::ELeft ); CAknButton::TAlignment verAlignment( CAknButton::ETop ); textButton->SetTextHorizontalAlignment( horAlignment ); textButton->SetTextVerticalAlignment( verAlignment ); // Preserve icon button aspect ratio iconButton->SetIconScaleMode( EAspectRatioPreserved ); // Help texts HBufC* helpText = StringLoader::LoadLC( R_MYAPP_HELPTEXT ); HBufC* dimmedHelpText = StringLoader::LoadLC( R_MYAPP_DIM_HELPTEXT ); // Set help text to current state textButton->State()->SetHelpTextL( *helpText ); // Set dimmed help text to all states textButton->SetDimmedHelpTextL( *dimmedHelpText ); CleanupStack::PopAndDestroy( 2 ); // helpText, dimmedHelpText // Help note timeout adjustments const TInt KButtonTimeoutBeforeNote = 300; const TInt KButtonTimeoutNoteInView = 5000; textButton->SetHelpNoteTimeouts( KButtonTimeoutBeforeNote, KButtonTimeoutNoteInView );