AsyncStorage

AsyncStorage 是一个简单的、具有异步特性的键值对的存储系统，用于全局，替代localStorage。

#所有方法都有一个回调函数，执行后，都会返回一个Promise对象

案例：判断首次渲染

import { AsyncStorage } from 'react-native';

class GetSetStorge {
    /**
     * 异步保存
     */
    setStorgeAsync(key, value) {
        return new Promise((resolve, reject) => {
            AsyncStorage.setItem(key, value, (error) => {
                if (error) {
                    console.log(`设置${key}失败${error}`);
                    reject(`设置${key}失败${error}`);
                } else {
                    console.log(`设置${key}成功`);
                    resolve(true);
                }
            });
        });
    }
    /**
     * 异步获取
     */
    getStorgeAsync(key) {
        return new Promise((resolve, reject) => {
            AsyncStorage.getItem(key, (error, result) => {
                if (error) {
                    console.log(`读取${key}失败` + error);
                    reject(`读取${key}失败${error}`);
                } else {
                    console.log(`读取${key}成功`);
                    resolve(result);
                }
            });
        });

    }

}
export default new GetSetStorge();

// 使用
···
     this.timer = setTimeout(() => {
            GetSetStorge.getStorgeAsync('isFrist').then((result) => {
                if (result == null || result == '') {
                    //第一次启动
                    this.props.navigation.navigate('GuideView');
                    GetSetStorge.setStorgeAsync('isFrist', 'true');
                } else {
                    //第二次启动s
                    this.props.navigation.navigate('GuideView');
                }
            }).catch((error) => {
                console.log('系统异常' + error);
            });
        }, 1000);
···