Method Object.toString(),referenced in method SettingActivity.saveDataButtons(),will not be accessible in module personal-health-assistant back up 29 oct  

Method String.trim(),referenced in method SettingActivity.setNullCurrentFocusedEditText(),will not be accessible in module personal-health-assistant back up 29 oct  

Method String.length(),will not be accessible in module personal-health-assistant back up 29 oct

我想知道

>如何发生这种情况？为什么有些方法不能在模块中访问？
是吗？
>如何解决这个警告？