//HeaderBar.jsx 子组件

import React, { Component } from 'react';

class Header extends Component {
  constructor() {
    super();
    this.handleClick = (e) => {
      console.log(this)
    }
  }

  renderLeftComponent() {

    let leftDOM = {};
    if (this.props.renderLeftComponent) {
      return this.props.renderLeftComponent();
    }

    if (this.props.showBack) {
      let backFunc = this.props.onBack || this.goBack;
      leftDOM = (<a onClick={backFunc.bind(this)}><i className="icon left-icon icon-left-arrow"></i></a>);
    }
    return leftDOM;
  }
  

  renderRightComponent() {
    if (this.props.renderRightComponent) {
      return this.props.renderRightComponent();
    }
  }

  goBack() {
    alert("返回上一页")
  }

  render() {
    return (
      <header className="header-bar">
        {this.renderLeftComponent()}
        <span>{this.props.title || '滴滴'}</span>
        {this.renderRightComponent()}
      </header>
    );
  }
}

export default Header;

//父亲组件部分代码App.jsx
import HeaderBar from "./components/Header";

let leftIcon = function () {
 return (
  <a><i className="icon left-icon icon-left-haha"></i>左边按钮</a>
 )
}
class App extends Component {

 render() {
  return (
   <div className="App">
    <HeaderBar title="滴滴打车" renderLeftComponent={leftIcon} />
   </div>
  );
 }
}

// Component 父级
class parentComponent extends React.Component {
  
  // add the following property
  static childContextTypes = {
    color: React.PropTypes.string
  }
  
  // 添加下面方法
  getChildContext() {
    return {
      color: "#f00"
    }
  }
  
  render() {
    <div>
      <Child1 />
    </div>
  }
}


// Component Child1
class Child1 extends React.Component {
  // 添加下面属性
  static contextTypes = {
    color: React.PropTypes.string
  }
  
  render() {
    <div>{this.context.color}</div>
  }
}