我有一个具有componentWillMount的react组件，并使用setState方法更新状态。我正在使用一个对象数组更新状态变量rideTiles，尽管我没有获取用于渲染的ant数据。我通过返回默认值shouldComponentUpdate()尝试了true，但仍未使用更新的值呈现组件。我无法确定出了什么问题？
这是我的代码
import React from 'react';
import {TouchableOpacity, Image, View, Text, StyleSheet, Dimensions, ScrollView} from 'react-native';
import Gradient from '../components/gradient';
import Icon from 'react-native-vector-icons/MaterialCommunityIcons';
import PRides from '../components/PRides'
import {GetRequest, GetUrl} from '../lib/net.js';
import Realm from '../lib/schemas.js';
import sqlite from '../lib/sqlite';
import config from '../../config.js';
import {DistanceAndTime} from '../lib/geoDistCal.js'
const AvroCodec = require('avroschema');
export default class Rides extends React.Component {
static navigationOptions = {
label: 'Rides',
tabBarIcon: () => (
<Image
source={require('../res/img/icn-ftrlnk2.png')}
style={[styles.img]}
/>
),
}
constructor(props){
super(props);
this.onRideData = this.onRideData.bind(this);
EE.addEventListener(EE.EVENT_TYPES.RIDE_DETAILS, this.onRideData);
this.eventCounts = 0;
this.insertedCount = 0;
this.rideTiles = [];
}
componentWillMount(){
var self = this;
GetRequest(GetUrl(config.glHost + "/gl/users/rides/findrides/?off=0&cnt=20&ist=false"), function(res){
if(res.status == 200){
var data = JSON.parse(res._response).data;
console.log("API data", data);
for(i = 0; i < data.length; i++){
Realm.write(() => {
Realm.create('Rides',{
idx: data[i].idx,
nm: data[i].nm,
sdt: data[i].sdt,
edt: data[i].edt,
flt: data[i].flt,
fln: data[i].fln,
tlt: data[i].tlt,
tln: data[i].tln,
uid: data[i].uid,
ist: data[i].ist,
isg: data[i].isg,
ec: data[i].ec,
// kms: data[i].kms,
// avs: data[i].avs,
// tps: data[i].tps
}, true);
self.insertLocationData(data[i]);
});
}
}
});
this.rideTiles = Array.from(Realm.objects('Rides'));
}
onRideData(event){
var self = this;
if(event){
var insertQuery = `insert into events (devId,rideId,ts,lat,lng,alt,spd,brg,hepe,vepe,ang,temp,motion,ignition,mainPower,relayState) values (
${event.devid}
,${event.rideid}
,${event.ts}
,${event.lat}
,${event.lng}
,${event.alt}
,${event.spd}
,${event.brg}
,${event.hepe}
,${event.vepe}
,${event.ang}
,${event.temp}
,${(event.motion ? 1 : 0)}
,${(event.ignition ? 1 : 0)}
,${(event.mainPower ? 1 : 0)}
,${(event.relayState ? 1 : 0)})`;
sqlite.runQuery(insertQuery, function(result){
console.log(result.rows);
if(result.rowsAffected === 1){
self.insertedCount += 1;
console.log("self.insertedCount, ", self.insertedCount, "self.eventCounts, ", self.eventCounts);
if(self.insertedCount === self.eventCounts){
//Completed Ride inserts, now compute tps avs and update in Realm
console.log("computing stats");
var tps, avs, kms, pingData = [];
sqlite.runQuery("select max(spd) as tps from events where rideId="+ event.rideid, function(result){
tps = result.rows.item(0).tps;
sqlite.runQuery(`select lat,lng,ts from events where rideId=${event.rideid} order by ts asc`, function(results){
var len = results.rows.length;
for (let i = 0; i < len; i++) {
pingData.push(results.rows.item(i));
}
console.log("pingData", pingData);
var stats = DistanceAndTime(pingData);
console.log("stats", stats);
kms = stats.D/1000;
avs = (5/18)*(stats.D/stats.T);
debugger
Realm.write(() => {
Realm.create('Rides', {idx:event.rideid, tps: Number(tps), kms: Number(kms), avs: Number(avs)}, true);
});
console.log("Before", self.rideTiles);
self.setState({rideTiles : Array.from(Realm.objects('Rides'))})
});
});
sqlite.runQuery('select distinct(ts) as ts from events', function(results){
var uniqueDate = [];
var len = results.rows.length;
for (let i = 0; i < len; i++) {
console.log(uniqueDate.indexOf(new Date(results.rows.item(i).ts*1000).toDateString()));
if(uniqueDate.indexOf(new Date(results.rows.item(i).ts*1000).toDateString()) === -1){
console.log("uniqueDate in if", uniqueDate);
uniqueDate.push(new Date(results.rows.item(i).ts*1000).toDateString());
}
}
uniqueDate.forEach(function(value){
var ts = ((new Date(value)).getTime()/1000).toFixed(0);
var tps, avs, kms, ang, dt = new Date(value);
sqlite.runQuery(`select lat,lng,ts from events where ts between ${ts} and ${ts+24*60*60} order by ts asc`, function(results){
var len = results.rows.length;
var pingData = [];
for (let i = 0; i < len; i++) {
pingData.push(results.rows.item(i));
}
var stats = DistanceAndTime(pingData);
console.log("stats", stats);
kms = stats.D/1000;
avs = (5/18)*(stats.D/stats.T);
console.log(`kms ${kms} avs : ${avs}`);
sqlite.runQuery(`select max(spd) as spd, max(ang) as ang from events where ts between ${ts} and ${ts+24*60*60}`, function(result){
tps = result.rows.item(0).spd;
ang = result.rows.item(0).ang;
console.log(`tps ${tps} ang : ${ang}`);
Realm.write(() => {
Realm.create('Stats', {top:tps, avg: avs, dis: kms, ang: ang, dt: dt }, true);
});
console.log('Stats', Array.from(Realm.objects('Stats')));
});
});
});
});
}
}
});
}
}
insertLocationData(ride){
var self = this;
sqlite.runQuery("select count(*) as count from events where rideId="+ ride.idx, function(result){
var sqlCount = result.rows.item(0).count;
console.log("sqlCount : ", sqlCount, "ride ec : ", ride.ec);
if(sqlCount !== ride.ec){
console.log("in ec eventCounts : ", self.eventCounts, "ride.ec, ", ride.ec);
self.eventCounts = ride.ec;
EE.emitEvent(EE.EVENT_TYPES.WS_REQ, AvroCodec.Encode({
devid: null,
rideid: ride.idx,
count: null,
offset: null,
tsFr: ride.sdt,
tsTo: Math.ceil(new Date()/1000)
}, AvroCodec.SCHEMA.A_REQ_FILTER)
);
}
});
}
render(){
return(
<View style={{flex:1}}>
<View style={[styles.posAbsolute, styles.gradient]}>
<Gradient.MainGradient height={430}/>
</View>
<View style={{zIndex:1,flex:1}}>
<PRides rides={this.rideTiles} navigation={this.props.navigation} />
</View>
</View>
)
}
}
const styles = {
img: {
height: 24,
width: 24,
},
gradient:{
left:0,
right:0
},
header:{
paddingTop:10,
paddingLeft:20,
paddingRight:20
},
posAbsolute: {
position: 'absolute',
},
}
答案 0 :(得分：0)
在渲染代码中，rideTiles未设置为state。
<View style={{zIndex:1,flex:1}}>
<PRides rides={this.rideTiles} navigation={this.props.navigation} />
</View>
要由setState函数进行更新，this.rideTiles必须为this.state.rideTiles，这应该在构造函数中初始化为：
this.state = {
rideTiles: []
};