小编Adi*_*ari的帖子

我正在尝试使用AngularFire2从我的Firebase获取数据.我想查看具体数据,在从Firebase获取此数据后,我只能在特定范围内检查,而不是在对Firebase进行操作后检查.为什么会这样？

以下是我的代码:

 this.af.database.list('/users/1qfcMAQnglX9jsW5GdLpPko1HqE2', { preserveSnapshot: true})
.subscribe(snapshots=>{
    snapshots.forEach(snapshot => {
      if(snapshot.key=="reg_boolean"){
        console.log(snapshot.val());
        this.bo=snapshot.val();
      }
      this.currentUser.push({key:snapshot.key,value:snapshot.val()});
      console.log(this.currentUser);
      //console.log(snapshot.key, snapshot.val());
      if(this.bo==true){console.log("happy"); }; //i can access only in this scope
    });

})
 if(this.bo==true){console.log("happy"); }; //why i can access this value??it's undefined, this happen before the subscribe with angularfire2

我在我的react-native v0.49应用程序上实现了检查互联网.我正在使用反应原生的NetInfo.我在发生任何更改时添加了eventListener,它将调用函数.但是当我在模拟器和真实设备中进行测试时,我只得到第一个更改,但如果我从Wifi断开连接,我看不到任何变化.

internetConnectionPopUp

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

// styles
import { style } from './style';
import { globalStyle } from '../../assets/styles/globalStyle';

// redux
import {connect} from 'react-redux';
import * as actions from '../../actions';

class InternetConnectionPopUp extends Component {
    constructor(props){
        super(props);
        this.state = { 
            connectionInfo : ''

         }
         this.handleFirstConnectivityChange = this.handleFirstConnectivityChange.bind(this);

    }  
    handleFirstConnectivityChange(connectionInfo) {
        this.setState({
            connectionInfo: connectionInfo.type
        })
        console.log('First change, type: ' + connectionInfo.type + ', effectiveType: ' + connectionInfo.effectiveType); …

我已经对我在笔记本电脑上工作的本地项目做出了反应。当我将项目转移到我的PC并运行yarn安装时（我使用yarn安装了一些模块，使用npm安装了一些模块）

发生意外错误：“ https://registry.yarnpkg.com/jest/-/jest-23.0.0-alpha.0.tgz：请求失败“找不到404”。

我的PC和Latop上的纱线版本相同

1.5.1

NPM版本我的电脑和笔记本电脑相同

5.4.1

节点版本

v 7.9.0

另外，在我的项目上运行yarn安装时，我会收到警告

warning You are using Node "7.9.0" which is not supported and may encounter bugs or unexpected behavior. Yarn supports the following semver range: "^4.8.0 || ^5.7.0 || ^6.2.2 || >=8.0.0"

我构建了一个 Firebase 云函数，用于查找 'IsNotificationEnabled' 值等于 true 的用户。我的功能的一部分

export const sendPushNotification = functions.https
.onRequest(async (req, res) => {
    try {
        const { message } = req.body;
        var usersRef = firebase.ref('/Users');
        var usersPushNotificationTokensRef = firebase.ref('/PushNotificationTokens')

        var listUsersSendNotifications = [],
            usersWithTokenSendNotifications = [],
            promises = [];
        if (message) {
            await usersRef.orderByChild('IsNotificationEnabled').equalTo(true).once('value', (snapshot) => {
                snapshot.forEach((childSnapshot) => {
                    console.log(childSnapshot.key)
                    listUsersSendNotifications.push(childSnapshot.key)

                    return false;
                })
            })
            ..........................

正如您在这里看到的，我正在寻找 IsNotificationEnabled = true 的用户。当我运行它时，我进入日志

[2018-05-22T09:12:57.352Z] @firebase/database: FIREBASE 警告：使用未指定的索引。您的数据将在客户端下载和过滤。考虑将 /Users 处的 ".indexOn": "IsNotificationEnabled" 添加到您的安全规则以获得更好的性能。

我在 firebase 控制台中插入的规则

    {
  "rules": …

我打开了一个新的react-native项目(最新版本V0.49),在安装了插件react-nfc-manager之后,我正在尝试使用XCode 9在ios上运行(我测试的模拟器:IPHONE 6,7,7s IOS 11它失败了,错误:

当我在Android上运行它工作正常.

我正在寻找一种方法来制作项目后的动画平面列表项目.当一个项目完成动画时,下一个项目(来自平面列表)将出现在屏幕上

class AnimatedFlatList extends React.PureComponent {
    state = {selected: (new Map(): Map<string, boolean>)};
    let data = {[
        {"first_name":"ltorrejon0@si.edu"},
        {"first_name":"ichadbourne1@icq.com"},
        {"first_name":"ascorthorne2@mediafire.com"},
        {"first_name":"jlathwood3@xing.com"},
        {"first_name":"molkowicz4@ftc.gov"},
        {"first_name":"motridge5@tiny.cc"},
        {"first_name":"rcess6@hostgator.com"},
        {"first_name":"mmaundrell7@php.net"},
        {"first_name":"ufairburne8@instagram.com"},
        {"first_name":"pangel9@biglobe.ne.jp"}]
    };

    _keyExtractor = (item, index) => item.id;

    _onPressItem = (id: string) => {
        // updater functions are preferred for transactional updates
        this.setState((state) => {
            // copy the map rather than modifying state.
            const selected = new Map(state.selected);
            selected.set(id, !selected.get(id)); // toggle
            return {selected};
        });
    };

    _renderItem = (item) => (
        <View style={Styles.viewItem}}>
            <Text …

我将cli更新为离子3版本,当我运行时

离子cordova运行android

构建apk文件并在android模拟器中运行我收到此错误

    C:\Users\XXXX\Desktop\beep>ionic cordova run android
Running app-scripts build: --address 0.0.0.0 --port 8100 --p 8100 --livereload-port 35729 --r 35729 --iscordovaserve --externalIpRequired --nobrowser

[20:52:20]  build dev started ...
[20:52:20]  clean started ...
[20:52:20]  clean finished in 11 ms
[20:52:20]  copy started ...
[20:52:20]  transpile started ...
[20:52:22]  transpile finished in 2.53 s
[20:52:22]  preprocess started ...
[20:52:22]  deeplinks started ...
[20:52:23]  deeplinks finished in 52 ms
[20:52:23]  preprocess finished in 54 ms
[20:52:23]  webpack started ...
[20:52:23]  copy finished in …

我打开了一个 Angular 4 项目，购买了 html 和 js 模板，我想让它一起工作，以便在我编写的样式下进入 angular-cli.json

  "styles": [\n        "../node_modules/bootstrap/dist/css/bootstrap.css",\n        "../node_modules/perfect-scrollbar/css/perfect-scrollbar.css",\n        "./assets/sass/material-dashboard.scss",\n        "./assets/css/demo.css",\n        "./assets/fonts/fonts.css",\n        "./assets/stylesheets/ionicons.min",\n        "./assets/stylesheets/fonts/fonts.css",\n        "./assets/stylesheets/bootstrap.css",\n        "./assets/stylesheets/isotope.css",\n        "./assets/stylesheets/venobox.css",\n        "./assets/stylesheets/slimmenu.css",\n        "./assets/stylesheets/main.css",\n        "./assets/stylesheets/main-bg.css",\n        "./assets/stylesheets/main-responsive.css"\n    ],\n

javascript

 "scripts": [\n        "../node_modules/jquery/dist/jquery.js",\n        "../node_modules/bootstrap/dist/js/bootstrap.js",\n        "../node_modules/bootstrap-material-design/dist/js/ripples.min.js",\n        "../node_modules/bootstrap-material-design/dist/js/material.min.js",\n        "../node_modules/arrive/src/arrive.js",\n        "../node_modules/moment/moment.js",\n        "../node_modules/perfect-scrollbar/dist/perfect-scrollbar.min.js",\n        "../node_modules/bootstrap-notify/bootstrap-notify.js",\n        "../node_modules/chartist/dist/chartist.js",\n        "./assets/javascripts/libs/common.js",\n        "./assets/javascripts/libs/bootstrap.min.js",\n        "./assets/javascripts/custom/main.js"\n    ],\n

我的角度 cli

{\n"$schema": "./node_modules/@angular/cli/lib/config/schema.json",\n"project": {\n    "name": "material-dashboard-angular"\n},\n"apps": [{\n    "root": "src",\n    "outDir": "dist",\n    "assets": [\n        "assets",\n        "favicon.ico"\n    ],\n    "index": "index.html",\n    "main": "main.ts",\n    "polyfills": "polyfills.ts",\n    "test": "test.ts",\n    "tsconfig": "tsconfig.app.json",\n    "testTsconfig": "tsconfig.spec.json",\n    "prefix": "app",\n    "styles": [\n …

我正在使用firebase/firestore,我正在寻找一种方法来返回快照的承诺.

onlineUsers(){
     // i want to return onSnapshot
    return this.status_database_ref.where('state','==','online').onSnapshot();
}

在我做的其他文件中

  componentDidMount(){
    // this.unsubscribe = this.ref.where('state','==','online').onSnapshot(this.onCollectionUpdate) 
    firebaseService.onlineUsers().then(e=>{
        console.log(e)
    })
}

我得到了错误

错误:Query.onSnapshot失败:使用无效参数调用.

TypeError:_firebaseService2.default.unsubscribe不是函数

如果我这样做

onlineUsers(){
   return  this.status_database_ref.where('state','==','online').onSnapshot((querySnapshot)=>{
        return querySnapshot
    }) 
}

我明白了

TypeError: _firebaseService2.default.onlineUsers(...).then is not a function

另外,当我这样做的时候

   this.unsubscribe = firebaseService.onlineUsers().then((querySnapshot)=>{
        console.log(querySnapshot.size)
        this.setState({count:querySnapshot.size})
    })

//其他文件

 onlineUsers(callback) {
    return this.status_database_ref.where('state', '==', 'online').get()
}

它没有听到更改为firebase,意味着如果我更改firebase它不更新或更改大小..

---- firestore函数---我试图使firestore函数在每次UserStatus节点更新时触发,但这需要几秒钟而且对我来说很慢.

module.exports.onUserStatusChanged = functions.database
.ref('/UserStatus/{uid}').onUpdate((change, context) => {
    // Get the data written to Realtime Database
    const eventStatus = change.after.val();

    // Then use other …

我正在尝试使用链接到业务页面从 React Native 应用程序打开 Facebook Messenger。我成功地为用户做到了这一点

Linking.openURL(`fb-messenger://user/1000XXXXXXXXX`)

但对于商业页面，例如此页面

我尝试过这种方式

   Linking.openURL(`fb-messenger://user//sport24live`)

或者

   Linking.openURL(`fb-messenger://sport24live`)

它不起作用，无法打开任何东西。