android - 如何从 React-Native 获取 onresume 事件？

Question

如何从 React-Native 获取 onresume 事件？我想检查一下 Android 主要 Activity 何时恢复。我检查了RN的源代码，但是应用程序恢复时似乎没有任何事件。

Answer 1

React Native 提供 AppState 来判断应用是在前台还是后台，并在状态发生变化时通知我们。

    import React, {Component} from 'react'
    import {AppState, Text} from 'react-native'

    class AppStateExample extends Component {

      state = {
        appState: AppState.currentState
      }

      componentDidMount() {
        AppState.addEventListener('change', this._handleAppStateChange);
      }

      componentWillUnmount() {
        AppState.removeEventListener('change', this._handleAppStateChange);
      }

      _handleAppStateChange = (nextAppState) => {
        if (this.state.appState.match(/inactive|background/) && nextAppState === 'active') {
          console.log('App has come to the foreground!')
        }
        this.setState({appState: nextAppState});
      }

      render() {
        return (
          <Text>Current state is: {this.state.appState}</Text>
        );
      }

    }

来源:https://facebook.github.io/react-native/docs/appstate.html