我正在使用mobx(和mobx-persist)作为我的反应本机应用程序全局存储(我正在使用expo客户端)。首先,我从服务器获取一些数据,然后将结果保存在存储中并将它们保存在asyncStorage中。它一开始工作正常,但突然当我尝试登录应用程序冻结然后崩溃时包含“原因:空指针取消引用”的摘要。以下是我的代码。
商店代码:
import { observable, computed, action, set } from 'mobx';
import { create, persist } from 'mobx-persist';
import { AsyncStorage } from 'react-native';
class Store {
URL = 'XX.XX.XX.XX'
@persist('object') @observable db = {
authToken: '',
buses: null,
term: null,
}
@computed get buses () {
return this.db.buses
}
@computed get term () {
return this.db.term
}
@computed get authToken () {
return this.db.authToken
}
@action setAuthToken = (token) => {
this.db.authToken = token;
}
@action setBuses = (buses) => {
this.db.buses = buses;
}
@action setTerm = (term) => {
this.db.term = term;
}
}
const hydrate = create({
storage: AsyncStorage,
jsonify: true
})
store = new Store()
storeLoader = async () => {
await hydrate('object', store)
return store
}
hydrate('object', store)
module.exports = { store, storeLoader }
登录屏幕代码:
import { store } from './store'
import { observer } from 'mobx-react';
fetch(`http://${store.URL}/login`, {
method: 'POST',
headers: {
'Content-Type': 'application/json',
},
body: JSON.stringify({
email: this.state.email,
password: this.state.password
})
}).then(res => res.json()).then(res => {
if (res.token) {
store.setAuthToken(res.token)
store.setTerm(res.term)
store.setBuses(res.buses.sort((a, b) => {
let first = a.fields[0].time, second = b.fields[0].time;
let firstArr = first.split(":", 2), secondArr = second.split(":", 2);
if (firstArr[0] !== secondArr[0])
return firstArr[0] - secondArr[0];
else
return firstArr[1] - secondArr[1];
}))
this.props.navigation.navigate("App")
}
if (res.error) {
this.setState({error: res.error})
}
}).catch(err => console.log(err))
AuthToken和术语都被保存,但总线在记录或崩溃时返回null。在调试和搜索几个小时后,我发现有些人面临类似的问题,因为他们试图保存大型嵌套对象,所以我想也许总线阵列实际上很大(但事实并非如此)所以我尝试用一把钥匙保存一个对象公共汽车的价值对但没有成功。
通过使用自定义类的持久列表修复:
在班级商店:
@persist('list', Bus) @observable Buses = []
并在班级巴士:
class Bus {
@persist @observable someField1 = ''
@persist @observable someField2 = false
@persist('list', field) @observable fields = []
}
甚至类Bus使用了另一个类字段:
class field {
@persist @observable someField1 = ''
@persist @observable someField2 = ''
}