Locks the device.
Example - Demo
function OnStart()
{
lay = app.CreateLayout( "linear", "VCenter,FillXY,touchspy" );
btn = app.CreateButton( "Disable", 0.3, 0.1 );
btn.SetOnTouch( btn_OnTouch );
lay.AddChild( btn );
app.AddLayout( lay );
}
function btn_OnTouch()
{
app.Lock();
app.ShowPopup( "Locked" );
}