react导航使用react上下文包装根AppContainer

createAppContainer() 方法,但它不起作用。

最后,我从中包装了一个应用程序容器 index.js 文件使用上下文的HOC,但当上下文的状态更改时,react导航似乎在重新呈现嵌套组件方面存在问题。我可以从嵌套组件访问上下文,但当上下文状态更改时,它们不会被呈现。

我的

import { AppRegistry } from "react-native";
import App from "./src/App";
import { withAppContextProvider } from "./src/AppContext";
import { name as appName } from "./app.json";

AppRegistry.registerComponent(appName, () => withAppContextProvider(App));

我的上下文类如下所示:

// for new react static context API
export const AppContext = createContext({});

// create the consumer as higher order component
export const withAppContext = ChildComponent => props => (
  <AppContext.Consumer>
    {context => <ChildComponent {...props} global={context} />}
  </AppContext.Consumer>
);

// create the Provider as higher order component (only for root Component of the application)
export const withAppContextProvider = ChildComponent => props => (
  <AppContextProvider>
    <ChildComponent {...props} />
  </AppContextProvider>
);

export class AppContextProvider extends Component {
  state = {
    isOnline: true
  };

  handleConnectivityChange = isOnline => {
    this.setState({ isOnline });
  };

  componentDidMount = async () => {
    NetInfo.isConnected.addEventListener(
      "connectionChange",
      this.handleConnectivityChange
    );
  };

  componentWillUnmount() {
    NetInfo.isConnected.removeEventListener(
      "connectionChange",
      this.handleConnectivityChange
    );
  }

  render() {
    return (
      <AppContext.Provider
        value={{
          ...this.state
        }}
      >
        {this.props.children}
      </AppContext.Provider>
    );
  }
}

我的 App.js 文件看起来像:

const HomeStack = createStackNavigator(
  {
    Home: HomeScreen,
    Cities: CitiesScreen
  },
  getStackConfig({ initialRouteName: "Home" })
);

const SettingsStack = createStackNavigator(
  {
    Settings: SettingsScreen
  },
  getStackConfig({ initialRouteName: "Settings" })
);

export default createAppContainer(
  createBottomTabNavigator(
    {
      Home: HomeStack,
      Settings: SettingsStack
    }
  )
);

CitiesScreen

import { AppContext } from "../AppContext";

class CitiesScreen extends Component {
  static contextType = AppContext;

  render() {
    return (
      <View style={styles.container}>
        <Text>This value should change on isOnline update: {this.context.isOnline}</Text>
      </View>
    );
  }
}

现在,当我访问上下文时,例如从 城市屏幕 组件,我当前可以获取 isOnline 上下文状态,但每当我打开/关闭internet连接(在android emulator上)时,上下文状态都会更改,但组件不会重新呈现,我的 shouldComponentUpdate() 方法不会被触发。有什么帮助吗?