用手机实现短信发送的源代码，通过AT指令发送-using cell phones to send text messages to achieve the source code, sent through the AT command

实现了在system权限下的屏幕截图，支持远程用at命令或登录到system用户进行截取用户桌面而非黑屏。-Under the authority of the system to achieve a screenshot, use the at command or remote system users to log in to intercept the user' s desktop instead of black.