React组件refs的使用详解

var App = React.createClass({
  getInitialState: function() {
   return {userInput: ''};
  },
  handleChange: function(e) {
   this.setState({userInput: e.target.value});
  },
  clearAndFocusInput: function() {
   this.setState({userInput: ''}); // 设置值为空字符串
        //这里想要实现获得焦点   
  },
  render: function() {
   return (
    <div>
     <input
      value={this.state.userInput}
      onChange={this.handleChange}
     />
          <input type="button"
           value="Reset And Focus"
           onClick={this.clearAndFocusInput}
        />
    </div>
   );
  }
 });

<input ref="myInput" />

this.refs.myInput

render: function() {
  return <TextInput ref={(c) => this._input = c} } />;
},
componentDidMount: function() {
  this._input.focus();
},

render: function() {
  return (
   <TextInput
    ref={function(input) {
     if (input != null) {
      input.focus();
     }
    }} />
  );
},

if(input != null){
     input.focus();
}

var App = React.createClass({
  getInitialState: function() {
    return {userInput: ''};
  },
  handleChange: function(e) {
    this.setState({userInput: e.target.value});
  },
  clearAndFocusInput: function() {
    this.setState({userInput: ''}); // Clear the input
    // We wish to focus the <input /> now!
    if (this.refs.myTextInput !== null) {
      this.refs.myTextInput.focus();
    }
  },
  render: function() {
    return (
      <div>
        <input
          value={this.state.userInput}
          onChange={this.handleChange}
          ref=”myTextInput”   
                     />
        <input
          type="button"
          value="Reset And Focus"
          onClick={this.clearAndFocusInput}
          />
      </div>
    );
  }
});
ReactDOM.render(
  <App />,
  document.getElementById('content')
);