javascript - Focusing div elements with React

Question

Is it possible to focus div (or any other elements) using the focus() method?

I've set a tabIndex to a div element:

<div ref="dropdown" tabIndex="1"></div>

And I can see it gets focused when I click on it, however, I'm trying to dynamically focus the element like this:

setActive(state) {
  ReactDOM.findDOMNode(this.refs.dropdown).focus();
}

Or like this:

this.refs.dropdown.focus();

But the component doesn't get focus when the event is triggered. How can I do this? Is there any other (not input) element I can use for this?

EDIT:

Well, It seems this it actually possible to do: https://jsfiddle.net/69z2wepo/54201/

But it is not working for me, this is my full code:

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

    this.state = {
      active: false,
      value: ""
    };
  }

  selectItem(color) {
    this.setState({ value: color, active: false });
  }

  setActive(state) {
    this.setState({ active: state });
    this.refs.dropdown.focus();
  }

  render() {
    const { colors, styles, inputName } = this.props;

    const pickerClasses = classNames('colorpicker-dropdown', { 'active': this.state.active });

    const colorFields = colors.map((color, index) => {
      const colorClasses = classNames('colorpicker-item', [`colorpicker-item-${color}`]);

      return (
        <div onClick={() => { this.selectItem(color) }} key={index} className="colorpicker-item-container">
          <div className={colorClasses}></div>
        </div>
      );
    });

    return (
      <div className="colorpicker">
        <input type="text" className={styles} name={inputName} ref="component" value={this.state.value} onFocus={() => { this.setActive(true) }} />
        <div onBlur={() => this.setActive(false) } onFocus={() => console.log('focus')} tabIndex="1" ref="dropdown" className={pickerClasses}>
          {colorFields}
        </div>
      </div>
    );
  }
}

Answer 1

React redraws the component every time you set the state, meaning that the component loses focus. In this kind of instances it is convenient to use the componentDidUpdate or componentDidMount methods if you want to focus the element based on a prop, or state element.

Keep in mind that as per React Lifecycle documentation, componentDidMount will only happen after rendering the component for the first time on the screen, and in this call componentDidUpdate will not occur, then for each new setState, forceUpdate call or the component receiving new props the componentDidUpdate call will occur.

componentDidMount() {
  this.focusDiv();
},
componentDidUpdate() {
  if(this.state.active)
    this.focusDiv();
},
focusDiv() {
  ReactDOM.findDOMNode(this.refs.theDiv).focus();
}

Here is a JS fiddle you can play around with.