如何缓存数据并在反应中获取? [英] How to cache data and fetch in reactnative?
本文介绍了如何缓存数据并在反应中获取?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我是 Reactnative 和 Javascript 的新手,我正在尝试从 APi 缓存数据并获取它.但它不起作用.我无法呈现数据.我收到错误.没有互联网时,如何从缓存中缓存和检索数据?我已经实现了如下缓存代码:
I am new to Reactnative and Javascript and I am trying to cache the data from APi and get it. But it is not working. I could not render the data. I am getting the error. How can I cache and retrieve data from cache when there is no internent? I have implemented the code for caching as follows:
export default class ViewpagerP extends Component {
constructor(props) {
super(props);
this.state = { isLoading: true, data: [] }
}
async componentDidMount() {
const photoStorage = await AsyncStorage.getItem('GalleryPhotos')
console.log(photoStorage);
if(!photoStorage) {
try {
console.log("Null inside")
const photoResp = await axios.get('https://rallycoding.herokuapp.com/api/music_albums')
console.log(photoResp)
const photoData = await JSON.stringify(photoResp.data);
this.setState({data:photoResp,isLoading:false})
await AsyncStorage.setItem('GalleryPhotos', photoData);
} catch(e) {
console.warn("fetch Error: ", error)
}
then(response => this.setState({ data: response.data,isLoading:false }))
}else{
this.getPhotos;
}
}
getPhotos = async()=> {
try {
data = JSON.parse(await AsyncStorage.getItem('GalleryPhotos'));
this.setState({data:data,isLoading:false})
console.log(data);
}
catch (error) {
console.error(error);
}
}
render() {
if (this.state.isLoading) {
return (
<View style={{ flex: 1, padding: 20 }}>
<ActivityIndicator />
</View>
)
}
console.log(this.state.data);
return (
<View style={styles.container}>
<ImageSlider style={styles.viewPagerStyle}
loopBothSides
autoPlayWithInterval={6000}
images={this.state.data}
customSlide={({ index, item, style, width }) => (
<View key={index} style={[style, styles.customSlideStyle]}>
<View style={styles.contentContainer}>
<Image source={{ uri: item.image }} style={styles.customImage} />
<View style={styles.textContainerStyle}>
<Text style={styles.textStyle}>{item.title}</Text>
</View>
</View>
</View>
)
}
/>
</View>
);
}
}
推荐答案
您需要对代码进行一些更正
this.getPhotos;
到
this.getPhotos();
您也可以使用
import { NetInfo} from 'react-native';
检查下面的文章它会帮助你在此处输入链接描述
Check the below artical it will help you enter link description here
这里来修正
export default class ViewpagerP extends Component {
constructor(props) {
super(props);
this.state = { isLoading: true, data: [] }
}
async componentDidMount() {
const photoStorage = await AsyncStorage.getItem('GalleryPhotos')
console.log(photoStorage);
if(!photoStorage) {
try {
console.log("Null inside")
const photoResp = await axios.get('https://rallycoding.herokuapp.com/api/music_albums')
console.log(photoResp)
const photoData = await JSON.stringify(photoResp.data);
this.setState({data:photoResp,isLoading:false})
await AsyncStorage.setItem('GalleryPhotos', photoData);
} catch(e) {
console.warn("fetch Error: ", error)
}
}else{
this.getPhotos();
}
}
getPhotos = async()=> {
try {
data = JSON.parse(await AsyncStorage.getItem('GalleryPhotos'));
this.setState({data:data,isLoading:false})
console.log(data);
}
catch (error) {
console.error(error);
}
}
render() {
if (this.state.isLoading) {
return (
<View style={{ flex: 1, padding: 20 }}>
<ActivityIndicator />
</View>
)
}
console.log(this.state.data);
return (
<View style={styles.container}>
<ImageSlider style={styles.viewPagerStyle}
loopBothSides
autoPlayWithInterval={6000}
images={this.state.data}
customSlide={({ index, item, style, width }) => (
<View key={index} style={[style, styles.customSlideStyle]}>
<View style={styles.contentContainer}>
<Image source={{ uri: item.image }} style={styles.customImage} />
<View style={styles.textContainerStyle}>
<Text style={styles.textStyle}>{item.title}</Text>
</View>
</View>
</View>
)
}
/>
</View>
);
}
}
这篇关于如何缓存数据并在反应中获取?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文