报错：‘Navigator is deprecated and has been removed from this package. It can now be installed ‘ +
‘and imported from `react-native-deprecated-custom-components` instead of `react-native`. ‘ +
‘Learn about alternative navigation solutions at http://facebook.github.io/react-native/docs/navigation.html‘
这是因为版本升级到0.43以上的话，Navigator不能直接从react-native里面获取了，
解决方案：
npm install react-native-deprecated-custom-components --save
然后在引用的地方
import {Navigator} from react-native-deprecated-custom-components