1 在react native 使用 http并思，默認是無法請求的，需要配置
https://github.com/expo/expo/issues/22887
"plugins": [
[
"expo-build-properties",
{
"android": {
"usesCleartextTraffic": true
}
}
]
]
"expo-build-properties": "^0.11.0",
https://github.com/devrdias/react-native-form4u/issues/13
2 equireNativeComponent: "RNCAndroidDropdownPicker" was not found in the UIManager.
npm install react-native-picker-select
