React native 如何在react native中从领域数据库读取数据?

React native 如何在react native中从领域数据库读取数据?,react-native,realm,React Native,Realm,我遵循react native中的realm db教程,成功地从db中创建、插入和删除数据,但从数据库中读取数据时遇到问题 我总是得到同样的结果,这是没有解决和无用的 我经常检查我的密码,但我找不出我的错误 这是我的密码: database.js import Realm from 'realm'; export const HEART_QUEUE_SCHEMA = 'HeartQueue'; export const HeartQueueSchema = { name : HEA

我遵循react native中的realm db教程,成功地从db中创建、插入和删除数据,但从数据库中读取数据时遇到问题

我总是得到同样的结果,这是没有解决和无用的

我经常检查我的密码,但我找不出我的错误

这是我的密码:

database.js

import Realm from 'realm';


export const HEART_QUEUE_SCHEMA = 'HeartQueue';

export const HeartQueueSchema = {
    name : HEART_QUEUE_SCHEMA,
    primaryKey : 'id',
    properties: {
        id : 'int', // primary key
        requestTime : {type : 'string', indexed: true}
    }
};

const databaseOptions = {
    path: 'mizWord.realm',
    schema : [HeartQueueSchema],
    schemaVersion : 0,
} 

export const insertToHeartQueue =  (item) => new Promise((resolve, reject) => {
    Realm.open(databaseOptions).then(realm => {
        realm.write(()=>{
            realm.create(HEART_QUEUE_SCHEMA, item);
            resolve(item);
        })
    }).catch((error) => reject(error));
});

export const updateHeartQueue =  (item) => new Promise((resolve, reject) => {
    Realm.open(databaseOptions).then(realm => {
        realm.write(()=>{
            let updatingRow = realm.objectForPrimaryKey(HEART_QUEUE_SCHEMA, item.id);
            updatingRow.requestTime = 'hello world';
            resolve();            
        })
    }).catch((error) => reject(error));
});

export const deleteHeartQueue =  (itemID) => new Promise((resolve, reject) => {
    Realm.open(databaseOptions).then(realm => {
        realm.write(()=>{
            let updatingRow = realm.objectForPrimaryKey(HEART_QUEUE_SCHEMA, itemID);
            realm.delete(updatingRow);
            resolve();            
        })
    }).catch((error) => reject(error));
});

export const deleteAllHeartQueue = () => new Promise((resolve, reject) => {
    Realm.open(databaseOptions).then(realm => {
        realm.write(()=>{
            let updatingRows = realm.objects(HEART_QUEUE_SCHEMA);
            realm.delete(updatingRows);
            resolve();            
        })
    }).catch((error) => reject(error));
});

export const getAllHeartQueue = () => new Promise((resolve, reject) => {
    Realm.open(databaseOptions).then(realm => {
        let allHeartsList = realm.objects(HEART_QUEUE_SCHEMA);
        resolve(allHeartsList);        
    }).catch((error) => reject(error));
});

export default new Realm(databaseOptions)


这是我的app.js文件


import realm from './databases';
import {insertToHeartQueue, deleteHeartQueue, deleteAllHeartQueue, getAllHeartQueue} from './databases'

export default class App extends Component {

constructor(){
  super();
  this.state = {
    data : "test",
    time : 0,
    testDB : '',
    xxxz : []
  }
}

_readDB = () => {    
  getAllHeartQueue().then((allHeartsList)=>{   
    console.log('data',allHeartsList);
    this.setState({
      xxxz : allHeartsList
    })   
  }).catch((err)=>{
    alert(err)
  }); 

}

  render() {   
    console.log('state', this.state.xxxz)
    return (
      <View style={styles.container}>  
        <Text style={styles.welcome}>Welcome to React Native!</Text> 
        <Text style={styles.welcome}>{this.state.time}</Text>
        <View>                   
          <Button
            onPress={()=> this._readDB()}
            title="Ask for Data"
            color="#cc77v"
            accessibilityLabel="Learn more about this purple button"
          />          
          <View>            
          </View>
        </View> 
      </View>
    );
  }
}



从“./数据库”导入域;
从“./databases”导入{insertToHeartQueue,deleteHeartQueue,deleteAllHeartQueue,getAllHeartQueue}
导出默认类应用程序扩展组件{
构造函数(){
超级();
此.state={
数据:“测试”,
时间:0,,
testDB:“”,
xxxz:[]
}
}
_readDB=()=>{
getAllHeartQueue()。然后((allHeartsList)=>{
console.log('data',allHeartsList);
这是我的国家({
xxxz:allHeartsList
})   
}).catch((错误)=>{
警报(错误)
}); 
}
render(){
console.log('state',this.state.xxxz)
返回(
欢迎来到这里!
{this.state.time}
这是.\u readDB()}
title=“询问数据”
color=“#cc77v”
accessibilityLabel=“了解有关此紫色按钮的详细信息”
/>          
);
}
}
但我总是这样:
代理{type:“object”,可选:false,Symbol(realm):140510983537104,Symbol(id):175,…}

尝试在写事务之外使用
resolve()

谢谢,你能告诉我如何使用resolve()更新代码吗?你可以在
realm.write()
中的代码块/回调中调用
resolve()
。我的建议是在
realm.write()之后调用
resolve()