React Native连接设备报错could not connect to development server

Hot loading is not working because it cannot connect to the development server. 

could not connect to development server

遇到以上三种错误,如果是adb断了就使用一下步骤 
1. adb reverse tcp:8081 tcp:8081 
2. npm start 
如果adb没断,直接 
1. npm start

感谢原作者:   weixin_38759990