ReactNative 学习笔记 物理back键

物理back键处理

需求 ：实现：点击back， 连续点击退出app

关键Code

_onBackPress = (event) => {
let nav = this.refs.navigator;
let routers = nav.getCurrentRoutes();
if (routers.length > 1) {
nav.pop();
return true;
} else {
if (this.lastBackPressed && this.lastBackPressed + 2000 >= Date.now()) {
//两秒内连续点back退出
return false;
}
this.lastBackPressed = Date.now();
ToastAndroid.show(Strings.backAgainToExit, ToastAndroid.SHORT);
return true;
}
}

componentWillMount() {
if (Platform.OS === 'android') {
BackAndroid.addEventListener('hardwareBackPress', this._onBackPress);
}
}

componetWillUnmount() {
if (Platform.OS === 'android') {
BackAndroid.removeEventListener('hardwareBackPress', this._onBackPress);
}
}