下面的代码是我从Github复制来学习的代码。
export default class App extends Component {
constructor(props){
super(props)
const ds = new ListView.DataSource({rowHasChanged: (r1, r2) => r1 !== r2})
this.state = {
isLoaded: false,
isOpenMenu: false,
dataSource: ds.cloneWithRows([]),
rotateY: new Animated.Value(0),
translateX: new Animated.Value(width),
menuAnimation: new Animated.Value(0),
text: '',
uid: '',
avatarUrl: '',
userName: '',
name: '',
url: ''
}
}
和componentWillMount如下所示，并且运行良好：
async componentWillMount() {
try {
let user = await firebase.auth().currentUser
this.getImageUrl(user.uid, (imageUrl) => {
this.setState({
avatarUrl: imageUrl
})
})
Helpers.getName(user.uid, (name) => {
this.setState({
userName: name
})
})
this.getUserRecipes(user.uid, (recipes) => {
if(recipes){
this.setState({
name: recipes.name,
url: recipes.url,
recipes: recipes.recipes,
dataSource: this.state.dataSource.cloneWithRows(recipes.recipes)
})
}
})
this.setState({
uid: user.uid
})
} catch(error){
console.log(error)
}
}
getUserRecipes(userId, callback){
let userNamePath = "/user/"+userId
firebase.database().ref(userNamePath).on('value', (snapshot) => {
let data = snapshot.val()
if(snapshot){
if(data.recipes){
let obj = {
name: data.details.name,
url: data.details.url,
recipes: data.recipes
}
callback(obj)
}
}
})
数据库的json文件如下：
{
"user" : {
"0SoP6VeIL3OYuIJuoO6ormnZSK53" : {
"details" : {
"bio" : "Male",
"name" : "MyName",
"place" : "Korea",
"url" : "https://firebasestorage.googleapis.com/v0/b/dribblechallengpractice.appspot.com/o/images%2F0SoP6VeIL3OYuIJuoO6ormnZSK53.jpg?alt=media&token=e8e2151f-2940-4a12-a353-a0b11611ac86"
},
"recipes" : {
"1539926978701" : {
"description" : "No description is dec",
"food" : "Foodname",
"image" : "https://firebasestorage.googleapis.com/v0/b/dribblechallengpractice.appspot.com/o/0SoP6VeIL3OYuIJuoO6ormnZSK53%2Fimages%2F1539926955047.jpg?alt=media&token=d55f6f0c-ce25-46af-b745-8997f0a89fa1",
"title" : "Waterfall"
},
"1539927054088" : {
"description" : "Dadasdsad dsa das",
"food" : "Fastfood",
"image" : "https://firebasestorage.googleapis.com/v0/b/dribblechallengpractice.appspot.com/o/0SoP6VeIL3OYuIJuoO6ormnZSK53%2Fimages%2F1539927021648.jpg?alt=media&token=112fa42c-7df6-45bd-895c-4d48821030ed",
"title" : "Second Title"
}
}
}
}
}
现在是问题。 当我使用自己的json数据库时，如下所示： （简化版）
{
"Detail" : {
"FirstCategory" : {
"itemname" : "item1",
"mainimage" : "https://firebasestorage.googleapis.com/v0/b/dribblechallengpractice.appspot.com/o/images%2F0SoP6VeIL3OYuIJuoO6ormnZSK53.jpg?alt=media&token=e8e2151f-2940-4a12-a353-a0b11611ac86",
"subbrands" : {
"brandA" : {
"subbrandsname" : "subname",
"description" : "No description is desc",
"image" : "https://firebasestorage.googleapis.com/v0/b/dribblechallengpractice.appspot.com/o/0SoP6VeIL3OYuIJuoO6ormnZSK53%2Fimages%2F1539926955047.jpg?alt=media&token=d55f6f0c-ce25-46af-b745-8997f0a89fa1",
"title" : "Waterfall",
"items" : {
"item1" : {
"price" : "500000",
"made" : "August, 13, 1985",
"itemimage" :"https://firebasestorage.googleapis.com/v0/b/dribblechallengpractice.appspot.com/o/0SoP6VeIL3OYuIJuoO6ormnZSK53%2Fimages%2F1539926955047.jpg?alt=media&token=d55f6f0c-ce25-46af-b745-8997f0a89fa1",
"userimage" : {
"0SoP6VeIL3OYuIJuoO6ormnZSK53" : {
"useritemimage" : "https://firebasestorage.googleapis.com/v0/b/dribblechallengpractice.appspot.com/o/0SoP6VeIL3OYuIJuoO6ormnZSK53%2Fimages%2F1539926955047.jpg?alt=media&token=d55f6f0c-ce25-46af-b745-8997f0a89fa1",
"useritemimagetext" : "hello"
}
}
},
"item2" :
}
},
"brandB" :
}
},
"SecondCategory" :{
"itemname" : "item2",
"mainimage" : "https://firebasestorage.googleapis.com/v0/b/dribblechallengpractice.appspot.com/o/images%2F0SoP6VeIL3OYuIJuoO6ormnZSK53.jpg?alt=media&token=e8e2151f-2940-4a12-a353-a0b11611ac86",
"subbrands" :
}
},
}
}
原始组件的WillMount代码及其修改版本，如下所示：
async componentWillMount() {
try {
let user = await firebase.auth().currentUser
this.getImageUrl(user.uid, (imageUrl) => {
this.setState({
avatarUrl: imageUrl
})
})
Helpers.getName(user.uid, (name) => {
this.setState({
userName: name
})
})
this.getUserData((item) => {
if(item){
this.setState({
name: item.name,
subname: item.subname,
image: item.image,
dataSource: this.state.dataSource.cloneWithRows(item)
})
}
})
this.setState({
uid: user.uid
})
} catch(error){
console.log(error)
}
}
getUserData(callback){
let userNamePath = "/FirstCategory/"
firebase.database().ref(userNamePath).on('value', (snapshot) => {
let data = snapshot.val()
if(snapshot){
if(data.item){
let obj = {
name: data.itemname,
subname: data.subbrands.brandA.subbrandsname,
image: data.subbrands.brandA.items.item1.itemimage
}
callback(obj)
}
}
})
}
该应用程序为空。 如何获得数据库中小写字母的对象而没有错误？