如何重置子元素的状态？

Question

假设我有三个元素保持状态计数器,点击时递增.

如果单击一个元素,如何将其他计数器重置为0？

https://jsfiddle.net/69z2wepo/56827

const Parent = React.createClass({
    render() {
        const rows = [];
        for (let i = 0; i < 3; i++) {
            rows.push(<Child key={i} />);
        }
        return (
            <ul>
                {rows}
            </ul>
        );
    }
});

const Child = React.createClass({
    getInitialState() {
        return {counter: 0};
    },
    handleClick() {
        this.setState({counter: ++this.state.counter });
    },
    render() {
        return (
            <div onClick={this.handleClick}>
                {this.state.counter}
            </div>
        );
    }
});

ReactDOM.render(
    <Parent />,
    document.getElementById('app')
);

Answer 1

如果您真的无法像其他答案所建议的那样将状态提升到父组件中，那么一种hacky 的方法就是更改key元素的道具。这会导致 React 卸载旧元素key并安装新实例。

class ChildComponent extends React.Component {
  state = {
    count: 0
  };
  render() {
    const { count } = this.state;
    return (
      <div>
        <div>count: {count}</div>
        <button onClick={() => this.setState({ count: count + 1 })}>Increment</button>
      </div>
    );
  }
}

class ParentComponent extends React.Component {
  state = {
    stateBustingKey: 0
  };
  render() {
    const { stateBustingKey } = this.state;
    return (
      <div>
        <ChildComponent key={stateBustingKey} />
        <button
          onClick={() =>
            this.setState({ stateBustingKey: stateBustingKey + 1 })
          }
        >
          Reset
        </button>
      </div>
    );
  }
}

ReactDOM.render(<ParentComponent />, 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" />

Answer 2

这会有点困难，因为您的Child组件正在管理自己的状态。

您可以将它们转换为哑组件并在组件中管理它们的状态Parent。

像这样的东西

const Parent = React.createClass({
    getInitialState() {
        return {counters: [0,0,0]};
    },
    handleClick(index){
       let newCounterState = this.state.counters.map(() => 0);
       newCounterState[index] = this.state.counters[index] + 1 ;
       this.setState({counters : newCounterState})
    },
    render() {
        const rows = this.state.counters.map((value,index) => (
            <Child 
               key={index}
               handleClick={() => this.handleClick(index)}
               counter={value}
            />
        ))
        return (
            <ul>
                {rows}
            </ul>
        );
    }
});

const Child = ({counter,handleClick}) => (
    <div onClick={handleClick}>
      {counter}
  </div>
)

ReactDOM.render(
    <Parent />,
    document.getElementById('app')
);

jsfiddle