I'm using react native class component and I'm using react-navigation to route in the app. the guide is mostly for the functional component and I'm trying to implement it with class components. but when i trying to get it from reactnavigation it always throws me error that navigation is not a function or undefined. Im sorry if this is an already asked question as I'm really new to this react native.
class component
import React from 'react';
import { useNavigation } from '#react-navigation/native';
import { Button, Divider, Layout, TopNavigation ,Card,Text} from '#ui-kitten/components';
class HomeScreen extends React.Component {
navigateDetails(navigation) {
debugger
navigation('Details');
};
constructor(props) {
super(props);
console.log(this.props);
this.state = { hover: false };
}
render() {
const navigation = this.props;
return(
<Button onPress={this.navigateDetails}>OPEN DETAILS</Button>
);
}
}
export default function (props) {
const navigation = useNavigation();
return <HomeScreen {...props} navigation={navigation} />;
}
First, you have to make sure navigation prop is exist in your class component (As looking in your code its already exist) and the second thing is this.props.navigation is an object, not a function which holds different function like navigate, push etc so you have to execute these functions, here are some changes I did in your code and I hope this will work for you.
class HomeScreen extends React.Component {
constructor(props) {
super(props);
console.log(this.props);
this.state = { hover: false };
}
navigateDetails() {
this.props.navigation.navigate('Details');
};
render() {
const navigation = this.props;
return(
<Button onPress={()=>this.navigateDetails()}>OPEN DETAILS</Button>
);
}
}
export default function (props) {
const navigation = useNavigation();
return <HomeScreen {...props} navigation={navigation} />;
}
Seems I have to pass that navigation to the function as a variable in order to work. so I have changed the function as bellow to pass the navigation to the
function and also changed this.navigateDetails(navigation) to
()=>this.navigateDetails(navigation)
also, I destructed the navigation like const {navigation} = this.props;
full code line
onPress={()=>this.navigateDetails(navigation)}
Related
I wish to add a check to every page in my app. The check is that if a file exists then pull the user to a page.
I think that a HOC is one way to do this (are there others?)
and I have come up with this
import React from "react";
import { NavigationScreenProp } from "react-navigation";
import RNFS from "react-native-fs";
interface MyComponentProps {
navigation: NavigationScreenProp<any, any>;
}
interface MyComponentState {}
const importFileCheck = WrappedComponent => {
class HOC extends React.Component<MyComponentProps, MyComponentState> {
constructor(props) {
super(props);
this.props.navigation.addListener("didFocus", () => {
RNFS.exists(
".\path\I\care\about.xml"
).then(exists => {
if (exists) {
this.props.navigation.navigate("Export");
}
});
});
}
render() {
return <WrappedComponent {...this.props} />;
}
}
return HOC;
};
export default importFileCheck;
When I run the page I get an error
TypeError: undefined is not an object (evaluating this.props.navigation.addListener)
So I guess that the navigation 'thing' is not being passed through properly
For completion I use the HOC like so
importFileCheck(App)
and App has the navigation stuff already in it, and works without the HOC.
Imports are
"react": "16.6.1",
"react-native": "0.57.7",
"react-navigation": "3.2.0"
Further details for the keen :D
First I make a stack navigator that is all the pages in my app
const appNav = createStackNavigator(
{
Calculator: {
screen: Calculator,
navigationOptions: { title: "Calculator" }
},
// more pages
);
export default createAppContainer(appNav);
In App.tsx
this gets 'wrapped' in other components
const WrappedStack = () => {
return <RootStack screenProps={{ t: i18n.getFixedT() }} />;
};
const ReloadAppOnLanguageChange = translate("translation", {
bindI18n: "languageChanged",
bindStore: false
})(WrappedStack);
class App extends React.Component {
public render() {
return (
<I18nextProvider i18n={i18n}>
<StyleProvider style={getTheme(material)}>
<Provider
ManureStore={ManureStore}
SettingsStore={SettingsStore}
FieldStore={FieldStore}
CalculatorStore={CalculatorStore}
FarmStore={FarmStore}
>
<ReloadAppOnLanguageChange />
</Provider>
</StyleProvider>
</I18nextProvider>
);
}
}
and finally we wrap with my new HOC
export default importFileCheck(App)
It's not easy to see what the error is when you have not provided any examples of how the component is used within react-navigation. Since the issue is related to the navigation prop not being passed it would be helpful to see a more complete example of how the HOC is used within the application, with all the react-navigation details.
That said, maybe you could try using the withNavigation HOC to ensure that the navigation prop is present. It is documented here:
https://reactnavigation.org/docs/en/connecting-navigation-prop.html
Well this defeated me (and the navigation event I wanted to use does not fire when an app returns from the background anyway)
this is my solution
import React, { Component } from "react";
import { NavigationScreenProp } from "react-navigation";
import RNFS from "react-native-fs";
import { AppState } from "react-native";
interface Props {
navigation: NavigationScreenProp<any, any>;
}
interface State {}
export default class ImportFileCheck extends Component<Props, State> {
private _handleAppStateChange = nextAppState => {
if (nextAppState === "active") {
RNFS.exists(
RNFS.DocumentDirectoryPath + "/Inbox/Import.json"
).then(exists => {
if (exists) {
this.props.navigation.navigate("Export");
}
});
}
};
constructor(props) {
super(props);
AppState.addEventListener("change", this._handleAppStateChange);
}
public componentWillUnmount() {
AppState.removeEventListener("change", this._handleAppStateChange);
}
public render() {
return null;
}
}
Then within each page files return statement I slap in a <ImportFileCheck navigation={navigation} />
What a hack!
We can use useNavigation hooks of react-navigation with version 5.x.x or later.
import { useNavigation } from '#react-navigation/native';
then initialize the navigation using useNavigation like
const navigation = useNavigation();
and then use navigation for different navigation actions like.
navigation.navigate('ToScreen');
naviagtion.goBack();
Hope this will help someone.
My App:
I am implementing a React Native application where a FlatList is used to display each item fullscreen. Each may contain/display several things, like Text, Images, GIFs. Also, some sound/song may be played. Think of this like a "enhanced" gallery/carousel.
My actual implementation is something like:
export default class App extends React.PureComponent {
this.state = {
currentIndex: null //currentIndex gets updated when displayed FlatList item changes
};
// Black magic here to update currentIndex
render() {
const data = [{image: "...", text: "...", sound: "..."}, {...},...]
return (
<FlatList
data = {data}
renderItem={({ item, index }) => {
const isDisplayed = this.state.currentIndex === index;
return <Thing {...item} isDisplayed={isDisplayed} />;
}}
...
/>
}
}
The Thing component is something similar to:
export default class Thing extends React.PureComponent {
render() {
if (this.props.isDisplayed){
<SoundComponent sound={this.props.sound}/>
<View>
<Text> this.props.text</Text>
<Image> this.props.image</Image>
</View>
}
}
My question:
Should I keep one SoundComponent per Thing, or should I use one global SoundComponent managed by and inside App? On one side I think that App should be unaware of how data is used, on the other side one centralized SoundComponent seems easier to orchestrate one sound at the time.
Notice that only one sound can be played at the same time.
There isn't any kind of "global" component in React. Every component has to be imported or passed as a prop. You have a few options if you want to avoid adding an import to each file though:
1) Create a Higher Order Component that renders the PageContent and the wrapped component.
import PageContent from './PageContent';
const withPageContent = WrappedComponent => {
return class extends React.Component {
render () {
return (
<PageContent>
<WrappedComponent />
</PageContent>
)
}
}
};
export default withPageContent;
// Usage
import withPageContent from './withPageContent';
class MyComponent extends React.Component {
render () {
return (
<div>
I'm wrapped in PageContent!
</div>
)
}
}
export default withPageContent(MyComponent);
2) Pass PageContent as a prop to a component:
import PageContent from './PageContent';
export default class App extends React.Component {
render() {
return (
<React.Fragment>
<Child1 content={PageContent} />
<Child2 content={PageContent} />
</React.Fragment>
)
}
}
// Usage
export default class Child1 extends React.Component {
render () {
const PageContent = this.props.content;
return (
<PageContent>
I'm wrapped in PageContent!
</PageContent>
)
}
}
export default class Child2 extends React.Component {
render () {
const PageContent = this.props.content;
return (
<PageContent>
I'm wrapped in PageContent!
</PageContent>
)
}
}
I'm fairly new to programming in general and even newer to JS and React(Native) but I have worked on this for an entire day now and I still haven't figured it out so I have resorted to Stack Overflow in hopes that someone can help me.
Basically what I want to accomplish is to set other Components as children of the App component because I want them to be able to access information that I will set in the state of App. However, at the same time, I am also using react-navigation to create bottom navigation bars and thus I have no idea on how I can pass props of App to these other Components such as the ExplorePage component which is representative of the other children components.
App
import React from 'react';
import ExplorePage from './app/tabs/ExplorePage';
import {createBottomTabNavigator} from 'react-navigation';
...other imports
class App extends React.Component {
state = {
parentState: 'testing testing',
}
}
const MainScreenNavigator = createBottomTabNavigator(
{
Home: {screen: ExplorePage},
Search: {screen: SearchPage},
Favorites: {screen: FavoritesPage},
}
);
export default MainScreenNavigator;
ExplorePage, which is just like SearchPage and FavoritesPage
...imports
export default class ExplorePage extends React.Component {
constructor(props) {
super(props);
this.state = {
}
}
componentDidMount() {
console.log(this.props.parentState ? this.props.parentState : "Parent state does not exist what do :(");
}
render(){
return(
<Text>Testing</Text>
)
}
And obviously every time the console prints that parentState does not exist. I thought that being in the same place would give the other components like ExplorePage props of App. Thanks for helping me!
for those who are looking for a React Navigation 5 solution, you can use initialParams like this:
<Stack.Navigator>
<Stack.Screen
name="screenName"
component={screenComponent}
initialParams={{key: value}}
/>
</Stack.Navigator>
You could pass a props using function. Try this
import React from 'react';
import ExplorePage from './app/tabs/ExplorePage';
import {createBottomTabNavigator} from 'react-navigation';
...other imports
class App extends React.Component {
state = {
parentState: 'testing testing',
}
render() {
// old
// const MainScreenNavigator = mainScreenNavigator(this.state.parentState);
const MainScreenNavigator = mainScreenNavigator(this.state);
return (
<MainScreenNavigator />
)
}
}
const mainScreenNavigator = value => createBottomTabNavigator(
{
// Home: { screen : props => <ExplorePage {...props} parentState={value} /> },
Home: { screen : props => <ExplorePage {...props} {...value} /> },
Search: {screen: SearchPage},
Favorites: {screen: FavoritesPage},
}
);
export default App;
Edit
First thing, I changed your MainScreenNavigator to be a function, as it is accepting state values dynamically.
Second thing, Instead of directly assigning { screen : Component }, I used function. This is the feature provided by reactnavigation. You can find about this in the documentation. ReactNavigation
If you want to pass multiple attributes then you can use es6 spread operator, as shown in the edit. {...value}, this will pass all the property of value to that component.
You should use Navigator Props "screenProps" as mentionned in API:
screenProps - Pass down extra options to child screens
On child screen, just take props via this.props.screenProps
I am trying to use my url as a parameter by passing the Match object into my react component class. However it is not working! What am I doing wrong here?
When I create my component as a JavaScript function it all works fine, but when I try to create my component as a JavaScript class it doesn't work.
Perhaps I am doing something wrong? How do I pass the Match object in to my class component and then use that to set my component's state?
My code:
import React, { Component } from 'react';
import axios from 'axios';
import PropTypes from 'prop-types';
class InstructorProfile extends Component {
constructor(props, {match}) {
super(props, {match});
this.state = {
instructors: [],
instructorID : match.params.instructorID
};
}
componentDidMount(){
axios.get(`/instructors`)
.then(response => {
this.setState({
instructors: response.data
});
})
.catch(error => {
console.log('Error fetching and parsing data', error);
});
}
render(){
return (
<div className="instructor-grid">
<div className="instructor-wrapper">
hi
</div>
</div>
);
}
}
export default InstructorProfile;
React-Router's Route component passes the match object to the component it wraps by default, via props. Try replacing your constructor method with the following:
constructor(props) {
super(props);
this.state = {
instructors: [],
instructorID : props.match.params.instructorID
};
}
Hope this helps.
Your constructor only receives the props object, you have to put match in it...
constructor(props) {
super(props);
let match = props.match;//← here
this.state = {
instructors: [],
instructorID : match.params.instructorID
};
}
you then have to pass that match object via props int a parent component :
// in parent component...
render(){
let match = ...;//however you get your match object upper in the hierarchy
return <InstructorProfile match={match} /*and any other thing you need to pass it*/ />;
}
for me this was not wrapping the component:
export default (withRouter(InstructorProfile))
you need to import withRouter:
import { withRouter } from 'react-router';
and then you can access match params via props:
someFunc = () => {
const { match, someOtherFunc } = this.props;
const { params } = match;
someOtherFunc(params.paramName1, params.paramName2);
};
Using match inside a component class
As stated in the react router documentation. Use this.props.match in a component class. Use ({match}) in a regular function.
Use Case:
import React, {Component} from 'react';
import {Link, Route} from 'react-router-dom';
import DogsComponent from "./DogsComponent";
export default class Pets extends Component{
render(){
return (
<div>
<Link to={this.props.match.url+"/dogs"}>Dogs</Link>
<Route path={this.props.match.path+"/dogs"} component={DogsComponent} />
</div>
)
}
}
or using render
<Route path={this.props.match.path+"/dogs"} render={()=>{
<p>You just clicked dog</p>
}} />
It just worked for me after days of research. Hope this helps.
In a functional component match gets passed in as part of props like so:
export default function MyFunc(props) {
//some code for your component here...
}
In a class component it's already passed in; you just need to refer to it like this:
`export default class YourClass extends Component {
render() {
const {match} = this.props;
console.log(match);
///other component code
}
}`
I have a scenario where I want to create an HOC that detects mouse events (e.g. mouseenter, mouseleave) when they occur on the HOC's WrappedComponent, then pass the WrappedComponent a special prop (e.g. componentIsHovered). I got this working by using a ref callback to get the wrapped component instance, then adding event listeners to the wrapped instance in my HOC.
import React, { Component } from 'react'
import ReactDOM from 'react-dom'
export default (WrappedComponent) => {
return class DetectHover extends Component {
constructor(props) {
super(props)
this.handleMouseEnter = this.handleMouseEnter.bind(this)
this.handleMouseLeave = this.handleMouseLeave.bind(this)
this.bindListeners = this.bindListeners.bind(this)
this.state = {componentIsHovered: false}
this.wrappedComponent = null
}
componentWillUnmount() {
if (this.wrappedComponent) {
this.wrappedComponent.removeEventListener('mouseenter', this.handleMouseEnter)
this.wrappedComponent.removeEventListener('mouseleave', this.handleMouseLeave)
}
}
handleMouseEnter() {
this.setState({componentIsHovered: true})
}
handleMouseLeave() {
this.setState({componentIsHovered: false})
}
bindListeners(wrappedComponentInstance) {
console.log('wrappedComponentInstance', wrappedComponentInstance)
if (!wrappedComponentInstance) {
return
}
this.wrappedComponent = ReactDOM.findDOMNode(wrappedComponentInstance)
this.wrappedComponent.addEventListener('mouseenter', this.handleMouseEnter)
this.wrappedComponent.addEventListener('mouseleave', this.handleMouseLeave)
}
render() {
const props = Object.assign({}, this.props, {ref: this.bindListeners})
return (
<WrappedComponent
componentIsHovered={this.state.componentIsHovered}
{...props}
/>
)
}
}
}
The problem is that this only seems to work when WrappedComponent is a class component — with functional components the ref is always null. I would just as soon place the WrappedComponent inside <div></div> tags in my HOC and carry out the event detection on that div wrapper, but the problem is that even plain div tags will style the WrappedComponent as a block element, which doesn’t work in my use case where the HOC should work on inline elements, too. Any suggestions are appreciated!
You can pass the css selector and the specific styles you need to the Higher Order Component like this:
import React, {Component} from 'react';
const Hoverable = (WrappedComponent, wrapperClass = '', hoveredStyle=
{}, unhoveredStyle={}) => {
class HoverableComponent extends Component {
constructor(props) {
super(props);
this.state = {
hovered: false,
}
}
onMouseEnter = () => {
this.setState({hovered: true});
};
onMouseLeave = () => {
this.setState({hovered: false});
};
render() {
return(
<div
className={wrapperClass}
onMouseEnter= { this.onMouseEnter }
onMouseLeave= { this.onMouseLeave }
>
<WrappedComponent
{...this.props}
hovered={this.state.hovered}
/>
</div>
);
}
}
return HoverableComponent;
};
export default Hoverable;
And use Fragment instead of div to wrap your component:
class SomeComponent extends React.Component {
render() {
return(
<Fragment>
<h1>My content</h1>
</Fragment>
)
}
And then wrap it like this
const HoverableSomeComponent = Hoverable(SomeComponent, 'css-selector');