score:271

Accepted answer

Any changes to the rendering should be change via the state or props (react doc).

So here I register the event of the input, and then change the state, which will then trigger the render to show on the footer.

var SearchResult = React.createClass({
  getInitialState: function () {
    return {
      site: '',
      address: '',
    };
  },
  onSiteChanged: function (e) {
    this.setState({
      site: e.currentTarget.value,
    });
  },

  onAddressChanged: function (e) {
    this.setState({
      address: e.currentTarget.value,
    });
  },

  render: function () {
    var resultRows = this.props.data.map(function (result) {
      return (
        <tbody>
          <tr>
            <td>
              <input
                type="radio"
                name="site_name"
                value={result.SITE_NAME}
                checked={this.state.site === result.SITE_NAME}
                onChange={this.onSiteChanged}
              />
              {result.SITE_NAME}
            </td>
            <td>
              <input
                type="radio"
                name="address"
                value={result.ADDRESS}
                checked={this.state.address === result.ADDRESS}
                onChange={this.onAddressChanged}
              />
              {result.ADDRESS}
            </td>
          </tr>
        </tbody>
      );
    }, this);
    return (
      <table className="table">
        <thead>
          <tr>
            <th>Name</th>
            <th>Address</th>
          </tr>
        </thead>
        {resultRows}
        <tfoot>
          <tr>
            <td>chosen site name {this.state.site} </td>
            <td>chosen address {this.state.address} </td>
          </tr>
        </tfoot>
      </table>
    );
  },
});

jsbin

score:-1

import React from 'react';
import './style.css';

export default function App() {
  const [currentRadioValue, setCurrentValue] = React.useState('on');
  const handleRadioChange = value => {
    setCurrentValue(value);
  };
  return (
    <div>
      <>
        <div>
          <input
            name="radio-item-1"
            value="on"
            type="radio"
            onChange={e => setCurrentValue(e.target.value)}
            defaultChecked={currentRadioValue === 'on'}
          />
          <label htmlFor="radio-item-1">Radio Item 1</label>
          {currentRadioValue === 'on' && <div>one</div>}
        </div>
        <div>
          <input
            name="radio-item-1"
            value="off"
            type="radio"
            onChange={e => setCurrentValue(e.target.value)}
            defaultChecked={currentRadioValue === 'off'}
          />
          <label htmlFor="radio-item-2">Radio Item 2</label>
          {currentRadioValue === 'off' && <div>two</div>}
        </div>
      </>
    </div>
  );
}

working example: https://stackblitz.com/edit/react-ovnv2b

score:1

Bootstrap guys, we do it like this:


export default function RadioButton({ onChange, option }) {
    const handleChange = event => {
        onChange(event.target.value)
    }

    return (
        <>
            <div className="custom-control custom-radio">
                <input
                    type="radio"
                    id={ option.option }
                    name="customRadio"
                    className="custom-control-input"
                    onChange={ handleChange }
                    value = { option.id }
                    />
                    <label
                        className="custom-control-label"
                        htmlFor={ option.option }
                        >
                        { option.option }
                    </label>
            </div>
        </>
    )
}

score:2

Clicking a radio button should trigger an event that either:

  1. calls setState, if you only want the selection knowledge to be local, or
  2. calls a callback that has been passed in from above self.props.selectionChanged(...)

In the first case, the change is state will trigger a re-render and you can do
<td>chosen site name {this.state.chosenSiteName} </td>

in the second case, the source of the callback will update things to ensure that down the line, your SearchResult instance will have chosenSiteName and chosenAddress set in it's props.

score:2

I also got confused in radio, checkbox implementation. What we need is, listen change event of the radio, and then set the state. I have made small example of gender selection.

/*
 * A simple React component
 */
class App extends React.Component {
  constructor(params) {
     super(params) 
     // initial gender state set from props
     this.state = {
       gender: this.props.gender
     }
     this.setGender = this.setGender.bind(this)
  }
  
  setGender(e) {
    this.setState({
      gender: e.target.value
    })
  }
  
  render() {
    const {gender} = this.state
    return  <div>
        Gender:
        <div>
          <input type="radio" checked={gender == "male"} 
onClick={this.setGender} value="male" /> Male
          <input type="radio" checked={gender == "female"} 
onClick={this.setGender} value="female"  /> Female
        </div>
        { "Select Gender: " } {gender}
      </div>;
  }
}

/*
 * Render the above component into the div#app
 */
ReactDOM.render(<App gender="male" />, document.getElementById('app'));
<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="app"></div>

score:2

To build upon ChinKang said for his answer, I have a more dry'er approach and in es6 for those interested:

class RadioExample extends React.Component {
  constructor(props) {
    super(props);

    this.state = {
      selectedRadio: 'public'
    };
  }

  handleRadioChange = (event) => {
    this.setState({
      selectedRadio: event.currentTarget.value
    })
  };

  render() {
    return (
      <div className="radio-row">
        <div className="input-row">
          <input
            type="radio"
            name="public"
            value="public"
            checked={this.state.selectedRadio === 'public'}
            onChange={this.handleRadioChange}
          />
          <label htmlFor="public">Public</label>
        </div>
        <div className="input-row">
          <input
            type="radio"
            name="private"
            value="private"
            checked={this.state.selectedRadio === 'private'}
            onChange={this.handleRadioChange}
          />
          <label htmlFor="private">Private</label>
        </div>
      </div>
    )
  }
}

except this one would have a default checked value.

score:2

@Tomasz Mularczyk mentions react hooks in his answer, but I thought I'd put in a solution I recently used that uses just the useState hook.

function Radio() {
  const [currentRadioValue, setCurrentRadioValue] = useState()

  const handleRadioChange = (e) => {
    setCurrentValue(e.target.value);
  };

  return ( 
    <>
      <div>
        <input
          id="radio-item-1"
          name="radio-item-1"
          type="radio"
          value="radio-1"
          onChange={handleRadioChange}
          checked={currentRadioValue === 'radio-1'}
        />
        <label htmlFor="radio-item-1">Radio Item 1</label>
      </div>
      <div>
        <input
          id="radio-item-2"
          name="radio-item-2"
          type="radio"
          value="radio-2"
          onChange={handleRadioChange}
          checked={currentRadioValue === 'radio-2'}
        />
        <label htmlFor="radio-item-2">
          Radio Item 1
        </label>
      </div>
    </>
  );
}

score:5

Here's what I have used. Hope this helps.
Defining variable first.

const [variableName, setVariableName] = useState("");

Then, we will need the actual radio buttons.

<input
   type="radio"
   name="variableName"
   value="variableToCheck"
   onChange={(e) =>
   setVariableName("variableToCheck")
   }
   checked={variableName === "variableToCheck"}
/>

score:8

import React, { Component } from "react";

class RadionButtons extends Component {
  constructor(props) {
    super(props);

    this.state = {
      // gender : "" , // use this one if you don't wanna any default value for gender
      gender: "male" // we are using this state to store the value of the radio button and also use to display the active radio button
    };

    this.handleRadioChange = this.handleRadioChange.bind(this);  // we require access to the state of component so we have to bind our function 
  }

  // this function is called whenever you change the radion button 
  handleRadioChange(event) {
      // set the new value of checked radion button to state using setState function which is async funtion
    this.setState({
      gender: event.target.value
    });
  }


  render() {
    return (
      <div>
        <div check>
          <input
            type="radio"
            value="male" // this is te value which will be picked up after radio button change
            checked={this.state.gender === "male"} // when this is true it show the male radio button in checked 
            onChange={this.handleRadioChange} // whenever it changes from checked to uncheck or via-versa it goes to the handleRadioChange function
          />
          <span
           style={{ marginLeft: "5px" }} // inline style in reactjs 
          >Male</span>
        </div>
        <div check>
          <input
            type="radio"
            value="female"
            checked={this.state.gender === "female"}
            onChange={this.handleRadioChange}
          />
          <span style={{ marginLeft: "5px" }}>Female</span>
        </div>
      </div>
    );
  }
}
export default RadionButtons;

score:10

Just an idea here: when it comes to radio inputs in React, I usually render all of them in a different way that was mentionned in the previous answers.

If this could help anyone who needs to render plenty of radio buttons:

import React from "react"
import ReactDOM from "react-dom"

// This Component should obviously be a class if you want it to work ;)

const RadioInputs = (props) => {
  /*
    [[Label, associated value], ...]
  */
  
  const inputs = [["Male", "M"], ["Female", "F"], ["Other", "O"]]
  
  return (
    <div>
      {
        inputs.map(([text, value], i) => (
	  <div key={ i }>
	    <input type="radio"
              checked={ this.state.gender === value } 
	      onChange={ /* You'll need an event function here */ } 
	      value={ value } /> 
    	    { text }
          </div>
        ))
      }
    </div>
  )
}

ReactDOM.render(
  <RadioInputs />,
  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>

score:24

Make the radio component as dumb component and pass props to from parent.

import React from "react";

const Radiocomponent = ({ value, setGender }) => ( 
  <div onChange={setGender.bind(this)}>
    <input type="radio" value="MALE" name="gender" defaultChecked={value ==="MALE"} /> Male
    <input type="radio" value="FEMALE" name="gender" defaultChecked={value ==="FEMALE"}/> Female
  </div>
);

export default Radiocomponent;

It's easy to test as it is a dumb component (a pure function).

score:40

Based on what React Docs say:

Handling Multiple Inputs. When you need to handle multiple controlled input elements, you can add a name attribute to each element and let the handler function choose what to do based on the value of event.target.name.

For example:

class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {};
  }

  handleChange = e => {
    const { name, value } = e.target;

    this.setState({
      [name]: value
    });
  };

  render() {
    return (
      <div className="radio-buttons">
        Windows
        <input
          id="windows"
          value="windows"
          name="platform"
          type="radio"
          onChange={this.handleChange}
        />
        Mac
        <input
          id="mac"
          value="mac"
          name="platform"
          type="radio"
          onChange={this.handleChange}
        />
        Linux
        <input
          id="linux"
          value="linux"
          name="platform"
          type="radio"
          onChange={this.handleChange}
        />
      </div>
    );
  }
}

Link to example: https://codesandbox.io/s/6l6v9p0qkr

At first, none of the radio buttons is selected so this.state is an empty object, but whenever the radio button is selected this.state gets a new property with the name of the input and its value. It eases then to check whether user selected any radio-button like:

const isSelected = this.state.platform ? true : false;

EDIT:

With version 16.7-alpha of React there is a proposal for something called hooks which will let you do this kind of stuff easier:

In the example below there are two groups of radio-buttons in a functional component. Still, they have controlled inputs:

function App() {
  const [platformValue, plaftormInputProps] = useRadioButtons("platform");
  const [genderValue, genderInputProps] = useRadioButtons("gender");
  return (
    <div>
      <form>
        <fieldset>
          Windows
          <input
            value="windows"
            checked={platformValue === "windows"}
            {...plaftormInputProps}
          />
          Mac
          <input
            value="mac"
            checked={platformValue === "mac"}
            {...plaftormInputProps}
          />
          Linux
          <input
            value="linux"
            checked={platformValue === "linux"}
            {...plaftormInputProps}
          />
        </fieldset>
        <fieldset>
          Male
          <input
            value="male"
            checked={genderValue === "male"}
            {...genderInputProps}
          />
          Female
          <input
            value="female"
            checked={genderValue === "female"}
            {...genderInputProps}
          />
        </fieldset>
      </form>
    </div>
  );
}

function useRadioButtons(name) {
  const [value, setState] = useState(null);

  const handleChange = e => {
    setState(e.target.value);
  };

  const inputProps = {
    name,
    type: "radio",
    onChange: handleChange
  };

  return [value, inputProps];
}

Working example: https://codesandbox.io/s/6l6v9p0qkr

score:153

Here is the simplest way of implementing radio buttons in react js.

class App extends React.Component {
  
  setGender(event) {
    console.log(event.target.value);
  }
  
  render() {
    return ( 
      <div onChange={this.setGender.bind(this)}>
        <input type="radio" value="MALE" name="gender"/> Male
        <input type="radio" value="FEMALE" name="gender"/> Female
      </div>
     )
  }
}

ReactDOM.render(<App/>, document.getElementById('app'));
<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="app"></div>

Edited

You can use arrow function instead of binding. Replace the above code as

<div onChange={event => this.setGender(event)}>

For a default value use defaultChecked, like this

<input type="radio" value="MALE" defaultChecked name="gender"/> Male

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