I have flatlist having images, videos. for images, I defined duration to show and then move to the next item in flatlist, but in case of the video once a video ended then move to next item.
I am using Redux for currentlyPlayingIndex and flatlist datasource.
If I have only images in flatlist it is working fine, but if I have a video, on video end I need to pass event from child to its parent. The parent calls the same method to move to the next index as for image duration end but the increment of currentlyPlayingIndex by one is not happening in case of video end.
parent component code or flatlist handler
import React, { Component } from 'react'
import { TouchableWithoutFeedback, View,StatusBar,Dimensions,FlatList } from 'react-native'
import {FileType,getFileType,getFileExtension} from '../services/FileManagerService'
import VideoPlayer from '../components/PlayerTypes/VideoPlayer'
import ImagePlayer from '../components/PlayerTypes/ImagePlayer'
import PdfPlayer from '../components/PlayerTypes/PdfPlayer'
import { ScaledSheet } from 'react-native-size-matters';
import NothingTpPlay from '../components/PlayerTypes/NothingTpPlay'
//redux
import {bindActionCreators} from 'redux';
import { connect } from 'react-redux';
import * as Actions from '../database/actions/ScheduleActions.js'; //Import your actions
import * as Animatable from 'react-native-animatable';
import constants from '../config/constants'
import KeepAwake from 'react-native-keep-awake';
import AudioPlayer from '../components/PlayerTypes/AudioPlayer'
import { showToastMessage } from '../utils/ToastMessage'
import I18n from "../locales/i18n-js";
import WebsitePlayer from '../components/PlayerTypes/WebsitePlayer'
import FullScreen from "../NativeBridgingHeader/FullScreen";
let deviceWidth = Dimensions.get('window').width
let deviceHeight = Dimensions.get('window').height
class PlaylistPlayerScreen extends Component {
constructor() {
super();
this.state = {
currentVisibleIndex:-1
}
this.playNextFile = this.playNextFile.bind(this)
this.videoEnded = this.videoEnded.bind(this)
this.schedulePlayDurationTimer = this.schedulePlayDurationTimer.bind(this)
this.viewabilityConfig = {
waitForInteraction: false,
itemVisiblePercentThreshold: 99,
}
}
static navigationOptions = {
header: null,
};
onViewableItemsChanged = ({ viewableItems }) => {
// viewableItems will show you what items are in view
// console.log("onViewableItemsChanged called" + JSON.stringify(viewableItems))
if(viewableItems.length >= 1) {
const visibleFileIndex = viewableItems[0].index
// console.log("visible index " + visibleFileIndex)
this.setState({currentVisibleIndex:visibleFileIndex})
const file = this.props.schedulesFiles[visibleFileIndex]
const fileType = getFileType(file)
console.log("file type is " + fileType)
if (fileType == FileType.Video) {
console.log("video file type")
} else {
this.schedulePlayDurationTimer(visibleFileIndex)
}
}
}
getItemLayout = (data, index) => ({
length: deviceWidth,
offset: deviceWidth * index,
index,
})
componentDidMount(){
this.props.getScheduleFiles()
}
shouldComponentUpdate(nextProps, nextState) {
return true
}
componentDidUpdate(){
console.log("componentDidUpdate")
}
schedulePlayDurationTimer(file_index) {
const file = this.props.schedulesFiles[file_index]
const playDuration = file.play_duration_in_milliseconds
this.timer = setTimeout(() => {
clearTimeout(this.timer)
this.playNextFile()
}, playDuration);
}
videoEnded = () => {
console.log("video ended")
this.playNextFile()
}
playNextFile = () => {
if(this.props.currentlyPlayingIndex == (this.props.schedulesFiles.length - 1)) {
//last file played
this.props.getScheduleFiles()
this.props.playNextFile(this.props.schedulesFiles,this.props.currentlyPlayingIndex)
this.listRef.scrollToIndex({animated: false, index: this.props.currentlyPlayingIndex})
} else {
console.log("playNextFile current index " + this.props.currentlyPlayingIndex)
this.props.playNextFile(this.props.schedulesFiles,this.props.currentlyPlayingIndex)
console.log("playNextFile next index " + this.props.currentlyPlayingIndex)
this.listRef.scrollToIndex({animated: true, index: this.props.currentlyPlayingIndex})
}
}
_renderItem = ({item, index}) => {
return (
this.renderPlayer(item,index)
);
}
renderPlayer(file,index) {
switch (getFileType(file)) {
case FileType.Video:
return <VideoPlayer file={file} onEnd={this.videoEnded} currentIndex={index} currentVisibleIndex={this.state.currentVisibleIndex} />
case FileType.Audio:
return <AudioPlayer file={file} onEnd={this.playNextFile} />
case FileType.Image:
return <ImagePlayer file={file} onEnd={this.playNextFile} />
case FileType.Pdf:
return <PdfPlayer file={file} onEnd={this.playNextFile} />
case FileType.WebpageContent:
return <WebsitePlayer file={file} onEnd={this.playNextFile} />
default:
showToastMessage(
I18n.t('ErrorMessage.FormatNotSupported', {
name: getFileExtension(file).toUpperCase()
})
)
this.playNextFile()
}
}
render() {
if(this.props.schedulesFiles.length > 0 ) {
return (
<View style={{flex:1}}>
<StatusBar hidden={true} />
<FlatList
style={{flex:1}}
bounces={false}
removeClippedSubviews={true}
scrollEnabled={false}
showsHorizontalScrollIndicator={false}
ref={el => this.listRef = el}
horizontal={true}
keyExtractor={(item, index) => index.toString()}
data={this.props.schedulesFiles}
renderItem={this._renderItem}
onViewableItemsChanged={this.onViewableItemsChanged}
viewabilityConfig={this.viewabilityConfig}
getItemLayout={this.getItemLayout}
initialNumToRender={2}
maxToRenderPerBatch={2}
windowSize={this.props.schedulesFiles.length}
/>
<KeepAwake />
</View>
)
}else {
return (
<TouchableWithoutFeedback delayLongPress={constants.REVEAL_SIDE_BAR_MENU_PRESS_DURATION} onLongPress={() => this.props.navigation.openDrawer()}>
<View style={styles.container}>
<NothingTpPlay/>
<KeepAwake />
</View>
</TouchableWithoutFeedback>
)
}
}
}
const styles = ScaledSheet.create({
container: {
flex:1,
backgroundColor : 'white',
}
});
//redux binding
// The function takes data from the app current state,
// and insert/links it into the props of our component.
// This function makes Redux know that this component needs to be passed a piece of the state
function mapStateToProps(state, props) {
return {
loading: state.scheduleReducer.loading,
schedulesFiles: state.scheduleReducer.data,
currentlyPlayingIndex: state.scheduleReducer.nextFileIndex,
}
}
// Doing this merges our actions into the component’s props,
// while wrapping them in dispatch() so that they immediately dispatch an Action.
// Just by doing this, we will have access to the actions defined in out actions file (action/home.js)
function mapDispatchToProps(dispatch) {
return bindActionCreators(Actions, dispatch);
}
//Connect everything
export default connect(mapStateToProps, mapDispatchToProps)(PlaylistPlayerScreen);
Render method for video player child component code is:
<VideoPlayer file={file} onEnd={this.videoEnded} currentIndex={index} currentVisibleIndex={this.state.currentVisibleIndex} />
VideoPlayer.js relevant code
export default class VideoPlayer extends React.Component {
constructor() {
super();
this.state = {
}
this.videoEnded = this.videoEnded.bind(this)
}
videoEnded() {
if (this.props.shouldRepeat == true) {
} else {
this.video.paused = true
this.video.seek(0)
}
this.props.onEnd()
}
render() {
return (
<Video
ref={ref => {
this.video = ref;
}}
onError={this.videoEnded}
minLoadRetryCount={1}
useTextureView={true}
controls={false}
style={ContainerStyle.playerTypeStyle}
onEnd={this.videoEnded}
repeat={this.props.shouldRepeat}
playInBackground={false}
playWhenInactive={false}
ignoreSilentSwitch={"ignore"}
resizeMode={this.props.file.resize_mode}
source={{uri:getFileAbsolutePath(this.props.file)}}
paused={this.props.currentIndex != this.props.currentVisibleIndex}
/>
)
}
}
Reducer code
import { combineReducers } from 'redux';
import { SCHEDULE_REFRESHED,PLAY_NEXT_FILE } from "../actions/ScheduleActions.js" //Import the actions types constant we defined in our actions
let dataState = { data: [], loading:true };
const scheduleReducer = (state = dataState, action) => {
switch (action.type) {
case SCHEDULE_REFRESHED:
state = Object.assign({}, state, { data: action.data, nextFileIndex:action.nextFileIndex });
return state;
case PLAY_NEXT_FILE:
state = Object.assign({}, state, { nextFileIndex: action.nextFileIndex});
return state;
default:
return state;
}
}
// Combine all the reducers
const rootReducer = combineReducers({
scheduleReducer
// ,[ANOTHER REDUCER], [ANOTHER REDUCER] ....
})
export default rootReducer;
Action code
//gets called initially on app launch to get files to be played
export function getScheduleFiles(){
return (dispatch) => {
getOfflineNextScheduleFiles().then((files)=>{//get offline files/schedule first
plainFiles = convertToArray(files)
dispatch({type: SCHEDULE_REFRESHED, data:plainFiles,nextFileIndex:0});
}).catch((error)=>{//if offline schedules is not available to play, refresh online
triggerPlaylistsRefresh().then((files)=>{
plainFiles = convertToArray(files)
dispatch({type: SCHEDULE_REFRESHED, data:plainFiles,nextFileIndex:0});
}).catch((error)=>{
console.log("nothing to play")
dispatch({type: PLAY_NEXT_FILE, nextFileIndex:0});
showToastMessage(I18n.t("ErrorMessage.NoSchedulesAvailableForCurrentTimeError"))
})
})
}
}
//get called from PlaylistPlayerScreen after each file played
export function playNextFile(files,filePlayedIndex){
return (dispatch) => {
if(filePlayedIndex < files.length-1) {
dispatch({type: PLAY_NEXT_FILE, nextFileIndex:filePlayedIndex+1});
}else {
console.log("all files played")
dispatch({type: PLAY_NEXT_FILE, nextFileIndex:0});
}
}
}
Related
I would like to add a progress indicator to Tesseract.js logging.
The example in docs works just fine, until setting a state hook into logger:
const worker = createWorker({
logger: (m) => {
setProgress(m) //new
}});
...
const [ocr, setOcr] = useState('Recognizing...');
const [progress, setProgress] = useState(null); //new
...
return (
<div className="App">
<p>
<LogComponent progress={progress}/> //new
</p>
</div>);
This causes the browser to slow down significantly (probably due React's way to re-render on each state update). Is there a way to get around this? Using React.memo perhaps?
You could design it into a hook so your entire component doesn't re-render. Here is a useTesseract hook you can use that I created: https://gist.github.com/KevinDanikowski/25cdcdda2ef4750bcf443f2027cc375a
Copy and Pasted:
import { useState, useEffect } from 'react'
import { createWorker } from 'tesseract.js'
export default function useTesseract({ tesseractLanguage = 'eng', log = false }) {
const [tesseractWorker, setTesseractWorker] = useState(null)
const [loadingModel, setLoadingModel] = useState(true)
const [modelError, setModelError] = useState(false)
const [imgResults, setImgResults] = useState({})
const [processing, setProcessing] = useState(false)
const [progress, setProgress] = useState(0)
const extractTextFromImage = (imageUrl) => {
const recognize = async () => {
const {
data: {
hocr: htmlOutput,
text,
// tsv, box, unlv
},
} = await tesseractWorker.recognize(imageUrl)
setProcessing(false)
setImgResults({ html: htmlOutput, text })
}
if (loadingModel) {
try {
setTimeout(recognize, 400)
} catch (e) {
console.error('Timeout Error:', e.message)
setImgResults({ error: true })
}
} else {
try {
setProcessing(true)
recognize()
} catch (e) {
console.error('Tesseract Error:', e.message)
setProcessing(false)
setImgResults({ error: true })
}
}
}
const logger = (m) => {
setProgress(m.progress)
if (log) {
console.info(m)
}
}
useEffect(() => {
const loadTesseract = async () => {
if (tesseractWorker) {
await tesseractWorker.loadLanguage(tesseractLanguage)
await tesseractWorker.initialize(tesseractLanguage)
console.info(`INFO: loaded ${tesseractLanguage} tesseract model`)
} else {
const tesseractWorker = createWorker({
logger,
// specify paths because sometimes the free CDN goes down
// corePath: '/static/tesseract-core.wasm.2.2.0.js',
// workerPath: '/static/tesseract-worker.v2.1.4.min.js',
})
setTesseractWorker(tesseractWorker)
await tesseractWorker.load()
await tesseractWorker.loadLanguage(tesseractLanguage)
await tesseractWorker.initialize(tesseractLanguage)
console.info(`INFO: loaded ${tesseractLanguage} tesseract model`)
setLoadingModel(false)
setModelError(true)
setLoadingModel(false)
}
}
loadTesseract().catch((e) => {
console.error(`ERROR: Failed to load tesseract model`, e.message)
setModelError(true)
setLoadingModel(false)
})
// TODO: Have to add a ref to reference the latest tesseractWorker in order to terminate
// return () => tesseractWorker.terminate()
}, [tesseractLanguage])
return {
imgResults,
loadingModel,
processing,
modelError,
progress,
extractTextFromImage,
}
}
I managed to implement and render the progress of the tesseract worker by putting my application render inside a class and using the setState method:
class App extends React.Component {
constructor(props){
super(props)
this.state = {
file: null
}
this.handleChange = this.handleChange.bind(this)
}
setProgress(m) {
if (m.progress !== 0 && m.progress !== 0.5 && m.progress !== 1){
var prog = "Progress: " + Math.round(m.progress*100) + "%"
this.setState({progress: prog})
}
}
worker = createWorker({
logger: m => this.setProgress(m),
});
doOCR = async () => {
await this.worker.load();
await this.worker.loadLanguage('eng');
await this.worker.initialize('eng');
const { data: { text } } = await this.worker.recognize(this.state.file);
this.setState({text: extractTotal(text),
progress: ""});
};
handleChange(event) {
this.setState({text: placeholder});
this.setState({
file: URL.createObjectURL(event.target.files[0]),
})
this.doOCR()
}
setText(input){
if (!input) {
return "Please select a receipt"
}
else {
return input
}
}
render() {
console.log("Text: " + this.state.text)
return (
<div className="container">
<p>{this.setText(this.state.text)}</p>
<p>{this.state.progress}</p>
<input type="file" onChange={this.handleChange}/>
<img src={this.state.file} className='logo' alt=""/>
</div>
);
}
}
We are going to implement a columnpicker and currently the only idea I have is to implement a ColumnPickableList that wraps a List. This would also hold a list of checkboxes that will enable the user to hide a column.
But before I go ahead do that I just wondered if I'm reinveting the wheel and if there is a simpler approach to solving this?
No simpler way. You'll have to implement your own List component for that
I'm following up on this since I'm struggling to make this work. Maybe it is because I have chosen to create a wrapper that filters the children to be displayed. So techically this approach doesn't implement its own List.
I have made a naive draft which I was hoping would work, but it fails to re-render the children even though they are changed/filtered in the parent component.
The console.log(..) in ColumnPickableList render()-function does print the correct children/props, but still the children won't update/re-render. Any clues as to why? Is this approach too naive?
So here is the current draft:
ColumnPicker.js
import React, { PropTypes } from 'react';
import Checkbox from 'material-ui/Checkbox';
export default class ColumnPicker extends React.Component {
constructor(props) {
super(props);
this.onCheck = this.onCheck.bind(this);
}
onCheck(column, isChecked) {
return this.props.onCheckboxChanged(column, isChecked);
}
renderCheckbox(column, onCheck) {
const disabled = (column.source === 'id');
return (<Checkbox key={column.source} label={column.source.toUpperCase()} onCheck={(event, checked) => onCheck(column, checked)} defaultChecked disabled={disabled} />);
}
render() {
const columns = this.props.columns || [];
return (
<div className="column-picker">
{columns.map((column) => {
return this.renderCheckbox(column, this.onCheck);
})}
</div>
);
}
}
ColumnPicker.propTypes = {
columns: PropTypes.array,
onCheckboxChanged: PropTypes.func,
};
ColumnPicker.defaultProps = {
columns: [], // [{source: myField, checked: true} ...]
};
ColumnPickableList.js:
import React, { PropTypes } from 'react';
import { connect } from 'react-redux';
import { List, Datagrid } from 'admin-on-rest';
import ColumnPicker from './ColumnPicker';
import { toggleColumnPickerStatusAction, initializeColumnPickerAction } from './actions';
export class ColumnPickableList extends React.Component {
componentWillMount() {
let columnSourceNames = [];
if (this.props.children) {
columnSourceNames = React.Children.map(this.props.children, (child) => {
return ({ source: child.props.source, checked: true });
});
}
const columnsDisplayed = columnSourceNames.filter((column) => column.source);
this.props.initializeColumnPicker(this.props.resource, columnsDisplayed);
}
shouldComponentUpdate(nextProps) {
const diff = nextProps.columnsDisplayed.filter((currentColumn) => {
return !this.props.columnsDisplayed.some((prevColumn) => {
return currentColumn.source === prevColumn.source && currentColumn.checked === prevColumn.checked;
});
});
return diff.length > 0;
}
removeHiddenColumns(children) {
return React.Children.map(children, (child) => {
if (!child.props.source) {
return child;
}
const column = this.props.columnsDisplayed.find((columnDisplayed) => {
return columnDisplayed.source === child.props.source;
});
if (this.props.columnsDisplayed.length === 0 || (column && column.checked)) {
return React.cloneElement(child);
}
return null;
});
}
render() {
const { children, ...rest } = this.props;
const displayedChildren = this.removeHiddenColumns(children);
console.log('Does it render? Rendering children', displayedChildren.map((child) => child.props.source));
return (
<div className="columnpickable-list">
<ColumnPicker columns={this.props.columnsDisplayed} onCheckboxChanged={this.props.handleCheckboxChanged} />
<List {...rest}>
<Datagrid>
{displayedChildren}
</Datagrid>
</List>
</div>
);
}
}
ColumnPickableList.propTypes = {
resource: PropTypes.string,
columnsDisplayed: PropTypes.array,
children: PropTypes.node,
initializeColumnPicker: PropTypes.func,
handleCheckboxChanged: PropTypes.func,
};
ColumnPickableList.defaultProps = {
columnsDisplayed: [],
};
function mapStateToProps(state) {
return {
columnsDisplayed: state.columnsDisplayed || [],
};
}
actions.js:
export const actions = {
INIT_COLUMNPICKER: 'INIT_COLUMNPICKER',
TOGGLE_COLUMNPICKER_STATUS: 'UPDATE_COLUMNPICKER_STATUS',
UPDATE_COLUMNPICKER_STATUSES: 'UPDATE_COLUMNPICKER_STATUSES',
}
export function initializeColumnPickerAction(resource, columns) {
return {
type: actions.INIT_COLUMNPICKER,
columns,
meta: { resource },
};
}
export function toggleColumnPickerStatusAction(column) {
return {
type: actions.TOGGLE_COLUMNPICKER_STATUS,
column,
};
}
reducers.js:
import { actions } from './actions';
function columnPickerReducer(state = [], action) {
switch (action.type) {
case actions.INIT_COLUMNPICKER: {
console.log('Init columnopicker reducer');
return action.columns;
}
case actions.TOGGLE_COLUMNPICKER_STATUS: {
const columns = state.map((column) => {
if (column.source === action.column.source) {
return { ...column, checked: !column.checked };
}
return column;
});
return columns;
}
default:
return state;
}
}
export default columnPickerReducer;
Example snippet of parent component:
...
<ColumnPickableList title="SillyStuff" {...props}>
<TextField source="id" />
<TextField source="NAME" />
<TextField source="SILLY_NAME" />
<TextField source="CHANGED_BY" />
<DateField source="CHANGED_TS" showTime />
<EditButton />
<DeleteButton />
</ColumnPickableList>
...
I have a reactjs component with redux which passes asynchronously props to child component.
In child component I try to catch the data in componentDidMount but somehow does not work either, however the child component is getting rendered.
This is my parent component
import React from 'react';
import {connect} from 'react-redux';
import {bindActionCreators} from 'redux';
import * as slidesActions from '../../actions/slidesActions';
import Slider from '../Partials/Slider'
import _ from 'underscore';
class HomePage extends React.Component {
constructor(props) {
super(props);
}
componentDidMount() {
this.props.actions.getSlides()
}
componentWillMount() {
const {slides} = this.props;
}
render() {
const {slides} = this.props;
return (
<div className="homePage">
<Slider columns={1} slides={slides} />
</div>
);
}
}
function mapStateToProps(state) {
return {
slides: state.slides
};
}
function mapDispatchToProps(dispatch) {
return {
actions: bindActionCreators(slidesActions, dispatch)
};
}
export default connect(mapStateToProps, mapDispatchToProps)(HomePage);
here comes my child component where I try to get passed slides props but is empty
import React from 'react';
import _ from 'underscore';
import Hammer from 'hammerjs';
class Slider extends React.Component {
constructor(props) {
super(props)
this.updatePosition = this.updatePosition.bind(this);
this.next = this.next.bind(this);
this.prev = this.prev.bind(this);
this.state = {
images: [],
slidesLength: null,
currentPosition: 0,
slideTransform: 0,
interval: null
};
}
next() {
const currentPosition = this.updatePosition(this.state.currentPosition - 10);
this.setState({ currentPosition });
}
prev() {
//TODO: work on logic
if( this.state.currentPosition !== 0) {
const currentPosition = this.updatePosition(this.state.currentPosition + 10);
this.setState({currentPosition});
}
}
componentDidMount() {
//here I try set a state variable on slides
let {slides} = this.props
let slidesLength = slides.length
this.setState({slidesLength})
this.hammer = Hammer(this._slider)
this.hammer.on('swipeleft', this.next);
this.hammer.on('swiperight', this.prev);
}
componentWillUnmount() {
this.hammer.off('swipeleft', this.next)
this.hammer.off('swiperight', this.prev)
}
updatePosition(nextPosition) {
const { visibleItems, currentPosition } = this.state;
return nextPosition;
}
render() {
let {slides, columns} = this.props
let {currentPosition} = this.state
let sliderNavigation = null
//TODO: this should go to slides actions
let slider = _.map(slides, function (slide) {
let Background = slide.featured_image_url.full;
if(slide.status === 'publish')
return <div className="slide" id={slide.id} key={slide.id}><div className="Img" style={{ backgroundImage: `url(${Background})` }} data-src={slide.featured_image_url.full}></div></div>
});
if(slides.length > 1 ) {
sliderNavigation = <ul className="slider__navigation">
<li data-slide="prev" className="" onClick={this.prev}>previous</li>
<li data-slide="next" className="" onClick={this.next}>next</li>
</ul>
}
return <div ref={
(el) => this._slider = el
} className="slider-attached"
data-navigation="true"
data-columns={columns}
data-dimensions="auto"
data-slides={slides.length}>
<div className="slides" style={{ transform: `translate(${currentPosition}%, 0px)`, left : 0 }}> {slider} </div>
{sliderNavigation}
</div>
}
}
export default Slider;
and here I have my actions for slider
import * as types from './actionTypes';
import axios from 'axios';
import _ from 'underscore';
//TODO: this should be accessed from DataService
if (process.env.NODE_ENV === 'development') {
var slidesEndPoint = 'http://dev.server/wp-json/wp/v2/slides';
} else {
var slidesEndPoint = 'http://prod.server/wp-json/wp/v2/slides';
}
export function getSlides () {
return dispatch => {
dispatch(setLoadingState()); // Show a loading spinner
axios.get(slidesEndPoint)
.then(function (response) {
dispatch(setSlides(response.data))
dispatch(doneFetchingData(response.data))
})
/*.error((response) => {
dispatch(showError(response.data))
})*/
}
}
function setSlides(data) {
return {
type: types.SLIDES_SUCCESS,
slides: data
}
}
function setLoadingState() {
return {
type: types.SHOW_SPINNER,
loaded: false
}
}
function doneFetchingData(data) {
return {
type: types.HIDE_SPINNER,
loaded: true,
slides: data
}
}
function showError() {
return {
type: types.SHOW_ERROR,
loaded: false,
error: 'error'
}
}
Reason is, componentDidMount will get called only once, just after the initial rendering, since you are fetching the data asynchronously so before you get the data Slider component will get rendered.
So You need to use componentwillreceiveprops lifecycle method.
componentDidMount:
componentDidMount() is invoked immediately after a component is
mounted. Initialization that requires DOM nodes should go here. If you
need to load data from a remote endpoint, this is a good place to
instantiate the network request. Setting state in this method will
trigger a re-rendering.
componentWillReceiveProps:
componentWillReceiveProps() is invoked before a mounted component
receives new props. If you need to update the state in response to
prop changes (for example, to reset it), you may compare this.props
and nextProps and perform state transitions using this.setState() in
this method.
Write it like this:
componentWillReceiveProps(nextProps){
if(nextProps.slides){
let {slides} = nextProps.props
let slidesLength = slides.length;
this.hammer = Hammer(this._slider)
this.hammer.on('swipeleft', this.next);
this.hammer.on('swiperight', this.prev);
this.setState({slidesLength})
}
}
As far as I understand, you are doing an axios call to fetch the data and then set it in the reducer which you are returning later. Also initially reducer data is empty . Now since componentDidMount is called only once, and initially no data may have been there you are not seeing any values. Use a componentWillReceiveProps function
componentWillReceiveProps(nextProps) {
//here I try set a state variable on slides
let {slides} = nextProps
let slidesLength = slides.length
this.setState({slidesLength})
this.hammer = Hammer(this._slider)
this.hammer.on('swipeleft', this.next);
this.hammer.on('swiperight', this.prev);
}
That's the component in question. Before the component is mounted, it successfully dispatches an action {this.props.populateGrid()}. Everything is fine, I can see the state in the logger (basically it's a nested array of random numbers). When I press the button, it should rehydrate the state with new random numbers. Yet, I get the following error: Cannot read property 'populateGrid' of undefined.
import React, { Component, PropTypes } from 'react';
import { View, StyleSheet, Button } from 'react-native';
import Grid from './Grid';
import * as globalStyles from '../styles/global';
export default class Body extends Component {
componentWillMount() {
this.refresh();
}
refresh() {
this.props.populateGrid();
}
render() {
return (
<View style={styles.body}>
<Grid inGrid={this.props.grid} />
<Button
onPress={this.refresh}
title={'Regenerate the Grid'}
/>
</View>
);
}
}
Container:
import { bindActionCreators } from 'redux';
import { connect } from 'react-redux';
import { listNumbers, pickNumber } from '../actions/numberActions';
import { populateRow, populateGrid } from '../actions/gridActions';
import Body from '../components/Body';
const mapStateToProps = state => ({
numbers: state.numbers,
grid: state.grid
});
const mapDispatchToProps = dispatch => (
bindActionCreators({
listNumbers,
pickNumber,
populateRow,
populateGrid
}, dispatch)
);
export default connect(
mapStateToProps,
mapDispatchToProps
)(Body);
Action:
import { POPULATE_ROW, POPULATE_GRID } from './actionTypes';
import { randNumbers, randGrid } from '../utils/generators';
export const populateRow = (n) => {
return {
type: POPULATE_ROW,
payload: randNumbers(n)
};
};
export const populateGrid = () => {
return {
type: POPULATE_GRID,
payload: randGrid()
};
};
reducer:
import { POPULATE_ROW, POPULATE_GRID } from '../actions/actionTypes';
export default (state = [], action = {}) => {
switch (action.type) {
case POPULATE_ROW:
return action.payload || [];
case POPULATE_GRID:
return action.payload || [];
default:
return state;
}
};
Generators of numbers (it's the second function in this case)
export const randNumbers = (n) => {
let numbers = new Array(n);
const shuffled = [];
// fill one array with the numbers 1-10
numbers = numbers.fill(1).map((_, i) => i + 1);
// shuffle by taking a random element from one array
// and pushing it to the other array
while (numbers.length) {
const idx = numbers.length * Math.random() | 0; // floor trick
shuffled.push(numbers[idx]);
numbers.splice(idx, 1);
}
return shuffled;
};
export const randGrid = () => {
const shuffled = randNumbers(6);
const array = shuffled.map(a => {
let r = new Array(6);
r = [a, ...randNumbers(5)];
return r;
});
return array;
};
I think you need to bind this to your refresh method in your onClick handler, so that this is set properly when refresh executes:
<Button
onPress={this.refresh.bind(this)}
title={'Regenerate the Grid'}
/>
Hope that helps!
This is the smart component:
import React from 'react';
import { connect } from 'react-redux';
import { bindActionCreators } from 'redux';
import Filter from '../Filter';
import Sort from '../Sort';
import { getItems, selectItem, reverseItems, findItems } from '../../actions/items';
import './app.css';
const App = ({filterList, sortList, onGetItems, onFindItems, reverseItems, onSelectItem}) => {
onGetItems();
return (
<div>
<Filter items={filterList} findText={onFindItems} reverseItems={reverseItems} selectItem={onSelectItem} />
<Sort items={sortList} selectItem={onSelectItem} />
</div>
)}
function mapStateToProps(state) {
return {
filterList: state.items.filter(item => item.name.includes(state.filter.toLowerCase())),
sortList: state.items,
}
}
function matchDispatchToProps(dispatch) {
return bindActionCreators({
onGetItems: getItems,
onSelectItem: selectItem,
onFindItems: findItems,
reverseItems: reverseItems
}, dispatch)}
export default connect(mapStateToProps, matchDispatchToProps)(App);
and actions:
let items = [];
(function onGetItems() {
let xhr = new XMLHttpRequest();
xhr.open('GET', '/items.json', false);
xhr.send();
if (xhr.status !== 200) {
console.log(xhr.status + ': ' + xhr.statusText);
} else {
items = JSON.parse(xhr.responseText.toLowerCase());
items.sort(function(a, b) {
if (a.name > b.name) return 1;
if (a.name < b.name) return -1;
return 0;
});
}
})();
export const getItems = () => dispatch => {
dispatch({ type: 'ADD_ITEMS', payload: items });
}
export const selectItem = (item) => {
console.log(item);
return {
type: "ITEM_SELECTED",
payload: item
}
};
export const reverseItems = (items) => {
console.log(items)
return {
type: "REVERSE_ITEMS",
payload: items.reverse()
}
};
export const findItems = (items) => {
return {
type: "FIND_ITEMS",
payload: items
}
};
and 2 reducers:
const initialState = '';
export default function filter(state = initialState, action) {
switch (action.type) {
case 'FIND_ITEMS': return action.payload;
default: return state
}
}
const initialState = [];
export default function items(state = initialState, action) {
switch (action.type) {
case 'ADD_ITEMS': return action.payload;
default: return state
}
}
The action reverseItems reverses the array, but the problem is that it doesn't rewrite state because it's formed by another action.
I realize that it's a basic issue, but I can't get how to do that.
Replace your
items.sort() statement with [...items].sort() which creates a new reference to the array and allows the re-rendering of the component. The sort function sorts the array using the same reference and does not cause a re-render.
Try to use Redux Thunk for your async calls.
You can dispatch an action, for example RECEIVED_ITEMS after your http request.