--删除光标处所在的字(半屏输入调用)
local txt,s=node.text,""
local gb=node.getTextSelectionEnd()
if gb>0 then
s=utf8.sub(txt,gb,gb)
if gb>=2 and gb<utf8.len(txt) then
txt=utf8.sub(txt,1,gb-1)..utf8.sub(txt,gb+1,-1)
elseif gb==1 then
txt=utf8.sub(txt,gb+1,-1)
else
txt=utf8.sub(txt,1,gb-1)
end
service.setText(node,txt)
service.setSelection(node,gb-1)
    service.speak(s.."已删除")
   else
service.beep()
 end