index.js

import React, {Component} from 'react';
import {View, Text, StatusBar, StyleSheet, Platform, BackHandler, ToastAndroid} from 'react-native';
import MyHeader from '../../component/Header';
import Navigation from '../../component/Navigation';
class Home extends Component {
  constructor(props) {
    super(props);
    this.state = {name: '地图'};
    this.changeName = this.changeName.bind(this);
    this.onBackAndroid=this.onBackAndroid.bind(this);
  }

  UNSAFE_componentWillMount() {

    if (Platform.OS === 'android') {
      BackHandler.addEventListener('hardwareBackPress', this.onBackAndroid);
    }
  }

  componentWillUnmount() {
    if (Platform.OS === 'android') {
      BackHandler.removeEventListener('hardwareBackPress', this.onBackAndroid);
    }
  }


  onBackAndroid = () => {

    //禁用返回键
    if (this.lastBackPressed && this.lastBackPressed + 2000 >= Date.now()) {
      BackHandler.exitApp(); //直接退出APP
    } else {
      this.lastBackPressed = Date.now();
      ToastAndroid.show('再按一次退出应用', 1000); //提示
      return true;
    }
  };

  changeName(name) {
    this.setState({
      name: name,
    });
  }

  render() {
    return (
      <View style={styles.container}>
        <MyHeader title={this.state.name} />
        <Navigation
          navigation={this.props.navigation}
          changeName={this.changeName}
        />
      </View>
    );
  }
}
const styles = StyleSheet.create({
  container: {
    backgroundColor: '#F2E2CE',
    // opacity: 0.5,
    flex: 1,
  },
  text: {
    fontSize: 50,
    fontWeight: 'bold',
    textAlign: 'center',
  },
});

export default Home;