Hides the device keyboard if it is currently shown.
Example - Toggle Keyboard
function OnStart()
{
lay = app.CreateLayout( "linear", "VCenter,FillXY" );
tgl = app.CreateToggle( "Keyboard", 0.3, 0.1 );
tgl.SetOnTouch( tgl_OnTouch );
lay.AddChild( tgl );
edt = app.CreateTextEdit( "Text", .8, .1 );
edt.Focus();
lay.AddChild(edt);
app.AddLayout( lay );
}
function tgl_OnTouch( show )
{
if( show ) app.ShowKeyboard( edt );
else app.HideKeyboard();
}