/**
 * Created by Administrator on 2016/9/12.
 */
import React, {Component} from 'react';
import {
  StyleSheet,
  View,
  Text,
  AsyncStorage
} from 'react-native';

var keyName = 'name';
var keyValue = '張三';
class AsyncStorageG extends Component {

  constructor(props) {
    super(props);
    this.state = {
      result: '初始值'
    };
  }

  render() {
    return (

      <View style={{flex: 1}}>
        <Text
          style={styles.text}
          onPress={this.save.bind(this)}>存</Text>
        <Text
          style={styles.text}
          onPress={()=>this.load()}>取</Text>
        <Text
          style={styles.text}
          onPress={()=> this.remove()}>刪除</Text>

        <Text
          style={styles.text}
        >存儲(chǔ)的內(nèi)容是------------------{this.state.result}</Text>
      </View>

    )
  }

  /**
   * 存數(shù)據(jù)
   */
  save() {
    //this 是指當(dāng)前對(duì)象
    this2 = this;
    AsyncStorage.setItem(keyName, keyValue, function (error) {
      if (error) {
        alert('存儲(chǔ)失敗');
      } else {
        this2.setState(
          {
            result: '數(shù)據(jù)已經(jīng)保存，取出來看看吧?。?！'
          }
        )
      }
    })
  }

  /**
   * 取數(shù)據(jù)
   */
  load() {
    //this 是指當(dāng)前對(duì)象
    this2 = this;
    AsyncStorage.getItem(keyName, function (error, result) {
      if (!error) {
        this2.setState(
          {
            result: result === null ? '數(shù)據(jù)已經(jīng)刪除，現(xiàn)在取的是空值' : result
          }
        )
      }
    })
  }

  /**
   * 兩個(gè)參數(shù)：
   * 一個(gè)是要?jiǎng)h除指定key內(nèi)容
   * 第二個(gè)是一個(gè)回調(diào)函數(shù)
   */
  remove() {
    //this 是指當(dāng)前對(duì)象
    this2 = this;
    AsyncStorage.removeItem(keyName, function (error) {

      if (!error) {
        this2.setState(
          {
            result: '數(shù)據(jù)已經(jīng)刪除'
          }
        )
      }

    })
  }

}

const styles = StyleSheet.create({
  text: {
    fontSize: 20
  }
});

//es6寫法
export default AsyncStorageG;