我遇到了一个非常奇怪的问题，我什至不知道从哪里开始调试，因为它只有在我将应用程序投入试飞时才会发生。基本上，我正在尝试根据地理位置加载频道。一些自动加载，如果距离山顶不到100英里，则某些会自动加载（让我们将它们称为PUBLIC和PRIVATE通道，它们都在同一列表中）。我在动作创建器中有这两个firebase调用，并将它们推送到数组中，然后再调用dispatch。我在FlatList上有一个问题，它在其中加载PUBLIC通道，并且只有在滚动时才对PRIVATE通道进行操作。我尝试了很多方法，包括该特定github问题（更新列表）中的最常见问题（“ removeClippedSubviews = {false}”），额外的数据，纯组件等，但均无用。
相反，我找到了解决此问题的方法（我知道这不是最好的方法，但是我只想要一种目前可行的解决方案），方法是设置超时时间并在调度操作之前等待频道：
setTimeout(function(){ dispatch(loadPublicChannelsSuccess(data)); }, 10);
不幸的是，现在是疯狂的问题出现了。基本上，它适用于调试，发布/我使用XCode尝试过的所有方法，但是当它进入我的设备时，render方法基本上位于加载指示器，直到我切换选项卡与反应导航。这对我来说是没有意义的，因为这种情况并非总是（可能是80％）发生在时间上，而且仅在迄今为止的试飞中才发生。在设置超时之前，我从未见过这个，所以也不确定是否从哪里开始：
render() {
const {loadPublicChannels, loading, publicChannels, checkedInMountain, selectedMountain} = this.props;
return !loadPublicChannels && publicChannels && !loading
? (
<MessagePanelPublic publicChannels={publicChannels} selectedMountain={selectedMountain}/>
) : (
<LoadingAnimation />
);
}
动作
export const getUserPublicChannels = () => {
return (dispatch, state) => {
dispatch(loadPublicChannels());
// get all mountains within distance specified
let mountainsInRange = state().session.mountainsInRange;
// get the user selected mountain
let selectedMountain = state().session.selectedMountain;
// see if the selected mountain is in range to add on additional channels
let currentMountain;
mountainsInRange
? (currentMountain =
mountainsInRange.filter(mountain => mountain.id === selectedMountain)
.length === 1
? true
: false)
: (currentMountain = false);
// mountain public channels (don't need to be within distance)
let currentMountainPublicChannelsRef = FIREBASE_REF_CHANNEL_INFO.child(
"Public"
)
.child(`${selectedMountain}`)
.child("Public");
// mountain private channels- only can see if within range (geolocation)
let currentMountainPrivateChannelsRef = FIREBASE_REF_CHANNEL_INFO.child(
"Public"
)
.child(`${selectedMountain}`)
.child("Private");
// get public channels
return currentMountainPublicChannelsRef
.orderByChild("key")
.once("value")
.then(snapshot => {
let publicChannelsToDownload = [];
snapshot.forEach(channelSnapshot => {
let channelId = channelSnapshot.key;
let channelInfo = channelSnapshot.val();
// add the channel ID to the download list
publicChannelsToDownload.push({ id: channelId, info: channelInfo });
});
// if mountain exists then get private channels/ if in range
if (currentMountain) {
currentMountainPrivateChannelsRef
.orderByChild("key")
.once("value")
.then(snapshot => {
snapshot.forEach(channelSnapshot => {
let channelId = channelSnapshot.key;
let channelInfo = channelSnapshot.val();
publicChannelsToDownload.push({
id: channelId,
info: channelInfo
});
});
});
}
return publicChannelsToDownload;
})
.then(data => {
setTimeout(function(){ dispatch(loadPublicChannelsSuccess(data)); }, 10);
});
};
};
与公共频道有关的减速器
case types.LOAD_PUBLIC_CHANNELS:
return {
...state,
loadPublicChannels: true
};
case types.LOAD_PUBLIC_CHANNELS_SUCCESS:
console.log("PUBLIC");
console.log(action.publicChannels);
console.log(action);
return {
...state,
publicChannels: action.publicChannels,
loadPublicChannels: false,
messages: {}
};
case types.LOAD_PUBLIC_CHANNELS_ERROR:
return {
...state,
channelsPublicError: action.error,
loadPublicChannels: false
};
调用mapStateToProps和mapDispatchToProps的容器
class MessagePanelPublicContainer extends Component {
constructor(props) {
super(props);
}
// get public and private channels from redux
async componentDidMount() {
this.props.getUserPrivateChannels();
this.props.loadCurrentUser();
// this.props.getUserPublicChannels();
}
componentDidUpdate(prevProps) {
if (this.props.mountainsInRange && prevProps.mountainsInRange !== this.props.mountainsInRange || prevProps.selectedMountain !== this.props.selectedMountain) {
this.props.getUserPublicChannels();
}
}
lessThan12HourAgo = (date) => {
return moment(date).isAfter(moment().subtract(12, 'hours'));
}
render() {
const {loadPublicChannels, loading, publicChannels, checkedInMountain, selectedMountain} = this.props;
return !loadPublicChannels && publicChannels && !loading
? (
<MessagePanelPublic publicChannels={publicChannels} selectedMountain={selectedMountain}/>
) : (
<LoadingAnimation />
);
}
}
const mapStateToProps = state => {
return {
publicChannels: state.chat.publicChannels,
loadPublicChannels: state.chat.loadPublicChannels,
currentUser: state.chat.currentUser,
loading: state.chat.loadCurrentUser,
mountainsInRange: state.session.mountainsInRange,
selectedMountain: state.session.selectedMountain,
};
}
const mapDispatchToProps = {
loadCurrentUser,
getUserPublicChannels,
};
export default connect(
mapStateToProps,
mapDispatchToProps
)(MessagePanelPublicContainer);
组件
import React, { Component } from "react";
import { View, Text, FlatList, ImageComponent } from "react-native";
import { connect } from "react-redux";
import PropTypes from "prop-types";
import { ListItem, Icon, Button } from "react-native-elements";
import { withNavigation } from "react-navigation";
import LinearGradient from "react-native-linear-gradient";
import styles from "./Styles";
import moment from 'moment';
import FastImage from 'react-native-fast-image';
class MessagePanelPublicComponent extends Component {
render() {
// rendering all public channels
const renderPublicChannels = ({ item }) => {
return (
<ListItem
leftAvatar={{
source: { uri: item.info.ChannelPicture },
rounded: false,
overlayContainerStyle: { backgroundColor: "white" },
ImageComponent: FastImage
}}
title={item.info.Name}
titleStyle={styles.title}
chevron={true}
bottomDivider={true}
id={item.Name}
containerStyle={styles.listItemStyle}
/>
);
};
const renderText = () => {
return (
<View style={styles.extraTextContainer}>
<Text style={styles.extraText}>
Get within 100 miles from resort or select a closer resort to see more channels...
</Text>
<Icon
name="map-marker"
type="font-awesome"
size={40}
iconStyle={styles.extraIcon}
/>
</View>
);
};
return (
<View style={styles.container}>
<View style={styles.channelList}>
<FlatList
data={this.props.publicChannels}
renderItem={renderPublicChannels}
// keyExtractor={item => item.Name}
keyExtractor={(item, index) => index.toString()}
extraData={this.props.publicChannels}
removeClippedSubviews={false}
/>
{this.props.publicChannels.length < 3 ? renderText() : null}
</View>
</View>
);
}
}