RN-AppState

ReactNative 提供了AppState 来告知 App当前状态：前台运行中、后台台运行中

1 获取当前应用状态

AppState.currentState

* active 前台运行中
* background 后台运行中
* inactive  运行的过渡状态

2 代码示例

/**
 * Created by licc on 2017/7/9.
 */

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

import NavigationBar from './NavigationBar'


export default class AppStateExample extends Component {

    componentWillMount(){

        //监听状态改变
        AppState.addEventListener('change', this.changeState);

        //监听内存报警
        AppState.addEventListener('memoryWarning', ()=>{console.log('内存报警....')});
    }

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

    changeState(state){
        alert('当前状态:'+state);
    }

    render() {
        return (
            <View style={styles.container}>
                <NavigationBar
                    title={'AlertIOS'}
                    statusBar={{backgroundColor:'blue'}}
                />
                <Text style={styles.item}>监听中...</Text>
            </View>
        );
    }
}

const styles = StyleSheet.create({

    container:{
        flex:1
    },

    item:{
        marginTop:10,
        marginLeft:5,
        marginRight:5,
        height:30,
        borderWidth:1,
        padding:6,
        borderColor:'#ddd',
        textAlign:'center'
    },
});