import React, { Component } from 'react'
import { connect } from 'react-redux'
#connect(
state=>state.user
)
class Profile extends Component {
logout(){
alert('logout')
}
render() {
const props = this.props
return props.user && (
<div>
<button onClick={()=>{this.logout()}}>Logout</button>
</div>
)
}
}
export default Profile
I click on the button, the alert is not triggered, no error no warning now I'm lost. What can be the possible cause?
I tried below code and everything seems fine. May be your this.props is not having any value. Can you share that code as well. I see everything is fine in component.
class Hello extends React.Component {
logout(){
alert('logout')
}
render() {
return (
<div>
<button onClick={()=>{this.logout()}}>Logout</button>
</div>
)
}
}
ReactDOM.render(
,
document
Related
I am trying to display/hide one component which is ItemMain and which is imported to the main App component using button in another component which is NavLogoNew. I tried to do this in many different ways but it looks like the button doesn't know if it's clicked, when I change true/false manually it works. In web I found a lot of stuff about situations when only two components are involved, but nothing like this. My code:
App
import React from 'react';
import './App.css';
import { tsPropertySignature } from '#babel/types';
import { statement } from '#babel/template';
import NavBar from './../Components/Navigation/NavBar/NavBar.js';
import ItemMain from './../Components/Item/ItemMain/ItemMain.js';
import ItemList from './../Components/Item/ItemList/ItemList.js';
import NavButtonTop from './../Components/Navigation/NavButton/NavButtonTop/NavButtonTop.js';
import NavLogoNew from './../Components/Navigation/NavButton/NavButtonNew/NavLogoNew.js';
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
visible: false
};
this.handleClick = this.handleClick.bind(this);
}
handleClick() {
this.setState({
visible: !this.visible
})
}
render() {
return (
<div className="App">
<NavBar />
{this.state.visible ? <ItemMain /> : null}
<ItemList />
<NavButtonTop name='UP'/>
</div>
);
}
}
export default App;
NavLogoNew:
import React from 'react';
import './NavLogoNew.css';
import ItemMain from './../../../Item/ItemMain/ItemMain.js'
class NavLogoNew extends React.Component {
render() {
return (
<button
className='NavLogoNew'
onClick={this.props.click}
>
{this.props.name}
</button>
);
}
}
export default NavLogoNew;
Your handleClick function is lacking something
use !this.state.visible so change from the below
handleClick(){
this.setState({
visible: !this.visible
})
}
to
handleClick = () => {
this.setState({
visible: !this.state.visible
})
}
pass the handleClick function to the NavLogoNew as follows
<NavLogoNew onClick = {this.handleClick} />
inside of the NavLogoNew component you should invoke it as follows
class NavLogoNew extends React.Component {
render() {
return (
<button
className='NavLogoNew'
onClick={() => this.props.onClick()}
>
{this.props.name}
</button>
);
}
}
My component is defined as follows:
import React, { Component } from "react";
import HOCName from "./HOCName";
class Hello extends Component {
render() {
return <h1>{this.props.name}</h1>;
}
}
export default HOCName(Hello);
MY HOC is defined as follows:
import React from "react";
export default WrappedComponent => props => {
const age = 23;
return (
<div>
<WrappedComponent {...props} age={age} />
<button>say Hello</button>
</div>
);
};
My question is how can I retrieve my button in my Component "Hello" ?
Thanks in advance for your help
You can choose one of the solutions
Pass button as a child of the passed component
Pass the button as a prop to the WrappedComponent
Here is an example of the two solutions
https://codesandbox.io/s/96q5ll9k4
The component I am trying to render:
import React, { Component } from 'react';
export default class QueryPrint extends Component {
render() {
console.log('working');
return (
<div>Hello</div>
)
}
}
The component that is trying to call it:
import React, { Component } from 'react';
import { connect } from 'react-redux';
import {
Button,
} from 'reactstrap';
import QueryPrint from './bq_print';
class QueryResults extends Component {
constructor(props) {
super(props);
this.print = this.print.bind(this);
}
print() {
console.log('Clicked');
return (
<QueryPrint />
);
}
render() {
return (
<Button
className='cuts-btn'
color='success'
onClick={this.print}
>
Print
</Button>
)
}
}
function mapStateToProps(state) {
return {
query_data: state.results.query_data
}
}
export default connect (mapStateToProps, null)(QueryResults);
The console.log('clicked') is working, but the component that is supposed to render in that method doesn't--no console.log('working') or <div>.
Returning something from a click callback has no effect. If you want to render something, you do so in the render method. The click callback's job is to call this.setState(), which will then kick off a render.
Perhaps something like this:
class QueryResults extends Component {
constructor(props) {
super(props);
this.print = this.print.bind(this);
this.state = {
queryPrint: false,
}
}
print() {
console.log('Clicked');
this.setState({ queryPrint: true })
}
render() {
const { queryPrint } = this.state;
return (
<React.Fragment>
{queryPrint && <QueryPrint />}
<Button
className='cuts-btn'
color='success'
onClick={this.print}
>
Print
</Button>
</React.Fragment>
)
}
}
React Native works differently. It is more like a web app - you need to navigate to the other component.
Look at this example its very to the point: https://facebook.github.io/react-native/docs/navigation
Alternatively if you want to make only part of the screen change you will need to include it into your own render and control it thru a flag or a state machine.
https://facebook.github.io/react-native/docs/direct-manipulation
For example, a component like this:
import React, { Component } from 'react';
import BodyContent from './BodyContent';
import BottomOne from './BottomOne';
import BottomTwo from './BottomTwo';
class App extends Component {
render() {
return (
<div className="App">
<BodyContent />
<BottomOne />
</div>
);
}
}
export default App;
I want to implement a function on BodyContent that unmount BottomOne and mounts BottomTwo instead, so when I activate the function, the code is reestructured to this:
import React, { Component } from 'react';
import BodyContent from './BodyContent';
import BottomOne from './BottomOne';
import BottomTwo from './BottomTwo';
class App extends Component {
render() {
return (
<div className="App">
<BodyContent />
<BottomTwo />
</div>
);
}
}
export default App;
I'm very new to React, so if there's a better way to do it, I'm open to suggestions, but I really need that end result, a function on BodyContent that unmounts BottomOne and mounts BottomTwo.
You can maintain a state which tells which component to render. Something roughly like this
import React, { Component } from 'react';
import BodyContent from './BodyContent';
import BottomOne from './BottomOne';
import BottomTwo from './BottomTwo';
class App extends Component {
changeBottomComponent = (comp) => {
this.setState({ showBottom: comp})
}
render() {
return (
<div className="App">
<BodyContent changeBottomComponent={this.changeBottomComponent}/>
{this.state.showBottom === 1 ? <BottomOne /> : <BotttomTwo />}
</div>
);
}
}
export default App;
To achieve that maintain a state variable in parent component (some kind of identifier for component) and use that state variable to render different component.
Along with that you also need to pass a function from parent to child and use that function to update the parent state value.
Like this:
class App extends Component {
constructor(){
super();
this.state={
renderOne: true,
}
this.update = this.update.bind(this);
}
update(){
this.setState({renderOne: false})
}
render() {
return (
<div className="App">
<BodyContent update={this.update}/>
{this.state.renderOne? <BottomOne /> : <BottomTwo/> }
</div>
);
}
}
Now inside BodyContent component call this.props.update() to render another component.
You can use state or props to render different components.
Example:
import React, {
Component
}
from 'react';
import BodyContent from './BodyContent';
import BottomOne from './BottomOne';
import BottomTwo from './BottomTwo';
class App extends Component {
constructor(props) {
super(props);
this.state = {
decider: false
};
}
render() {
const bottomContent = this.state.decider === true ? <BottomOne /> : <BottomTwo />;
return (
<div className="App">
<BodyContent />
{ bottomContent }
</div>
);
}
}
export
default App;
You can also directly use the components in the state and render them. Could be more flexible this way.
const BottomOne = () => <div>BottomOne</div>;
const BottomTwo = () => <div>BottomTwo</div>;
class Example extends React.Component {
constructor() {
super();
this.state = { show: BottomOne };
this.toggleComponent = this.toggleComponent.bind(this);
}
toggleComponent() {
// Use whatever logic here to decide.
let show = BottomOne;
if (this.state.show === BottomOne) {
show = BottomTwo;
}
this.setState({ show });
}
render() {
return (
<div>
<button onClick={this.toggleComponent}>Change</button>
<this.state.show />
</div>
);
}
}
ReactDOM.render(<Example />, document.getElementById('root'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="root"></div>
I need advice on how to pass a Reactjs prop from a component to my app when it's loaded. I'm able to pass the value when my props are in app.js but how do I handle the prop when loading from a separate component?
Here's what's working so far in app.js:
import React, { PropTypes, Component } from 'react';
import { Grid, Nav, Navbar, NavItem, Jumbotron } from 'react-bootstrap';
import { Link } from 'react-router';
import { LinkContainer, IndexLinkContainer } from 'react-router-bootstrap';
function HeaderTitle(props) {
return <h1>{props.name}</h1>;
}
const headerTitle = <HeaderTitle name="About Page" />;
class App extends React.Component {
constructor(props) {
super(props);
}
render() { ...
<p>{headerTitle.props.name}</p>
Parent to Child
If you want to pass all the props through:
render() {
return (
<div>
<HeaderTitle {...this.props} />
</div>
);
}
Or if just some:
render() {
return (
<div>
<HeaderTitle name={this.props.name} />
</div>
);
}
Child to Parent
If you mean the other way round, you need to use a callback
// app
render() {
return (
<div>
<HeaderTitle onGetName={(name) => this.setState({childName: name})} />
<p>{this.state.childName}</p>
</div>
);
}
// headertitle
componentDidMount() {
// maybe some async call or something
axios
.get('/api/say-my-name')
.then(response => this.props.onGetName(response.data);
}
So I guess you need some thing like importing components from one file to another. So you have options to import and export components from another file since React components are basically Objects. In index.js if you have something like
const headerTitle = <HeaderTitle name="About Page" />;
export default headerTitle;
and in app.js
import React, { PropTypes, Component } from 'react';
import { Grid, Nav, Navbar, NavItem, Jumbotron } from 'react-bootstrap';
import { Link } from 'react-router';
import { LinkContainer, IndexLinkContainer } from 'react-router-bootstrap';
import HeaderTitle from '/// put the file relative location to app.js"
function HeaderTitle(props) {
return <h1>{props.name}</h1>;
}
class App extends React.Component {
constructor(props) {
super(props);
}
render() { ...
<p>{headerTitle.props.name}</p>
}