Touch-enabled devices include varying sets of physical keys. Some
devices include only a few basic keys, while others include a full
keyboard. For backwards-compatibility with Canvas-based MIDlets that rely on key input, the touch UI on Symbian
devices provides an on-screen keypad (OSK) that simulates the physical
keys found on devices without a touch screen. Events from the available
keys in the on-screen keypad map the same way as events from physical
keys.
Note: Usage of OSK is recommended only for applications which do not handle touch events at all (non-touch MIDlets). It is also recommended that new applications developed for touch devices have their own interaction buttons for usability and visual appearance reasons.
To control the on-screen keypad, use the Nokia-MIDlet-On-Screen-Keypad JAD attribute.
By default, the on-screen keypad behaves as follows:
On S60 5th Edition devices, the on-screen keypad is enabled
by default for every Canvas-based MIDlet. To
disable the on-screen keypad for a MIDlet, use the Nokia-MIDlet-On-Screen-Keypad attribute.
From Symbian^3 onwards, the Java Runtime automatically detects
the need for the on-screen keypad when a Canvas-based MIDlet is installed, and disables or enables the keypad accordingly
for the MIDlet. During installation, the Java Runtime checks if the
MIDlet uses any classes that are inherited from javax.microedition.lcdui.Canvas and whether
those classes implement any of the following methods:
protected void pointerDragged(int x, int y)
protected void pointerPressed(int x, int y)
protected void pointerReleased(int x, int y)
If the MIDlet contains at least one Canvas-based class that implements at least one of the above methods, the
MIDlet is considered touch-compatible and the on-screen keypad is
disabled. If the MIDlet contains Canvas-based
classes, but does not implement the above methods, or provides empty
implementations of them, the MIDlet is considered touch-incompatible
and the on-screen keypad is enabled.
If you define a valid value
for the Nokia-MIDlet-On-Screen-Keypad JAD attribute,
the Java Runtime skips automatic detection and enables or disables
the on-screen keypad as per the attribute value.
Note: Usage of OSK is recommended only for applications which do not handle touch events at all (non-touch MIDlets). It is also recommended that new applications developed for touch devices have their own interaction buttons for usability and visual appearance reasons.
Touch-enabled devices offer different kinds on-screen keypads for Canvas applications. For more detailed instructions on
using on-screen keypads on devices, see the following sections: