尝试根据游戏是否结束来更改文本 react.js

Question

我做了一个井字游戏（react 自己的文档），现在我正在尝试更改一些功能，在这种情况下，我更改的第一件事是用户可以在游戏完成后观察之前的动作超过。我已经想出了我正在寻找的结果，但是我必须再单击一次才能使获胜者值发生变化，因此，要使底部按钮出现（让您浏览游戏历史的按钮移动通过移动）。你知道是什么原因造成的吗？我该如何解决？

这是我的代码： （我尝试了几种解决方案，但都没有奏效，我不知道是什么原因导致了这个问题，这就是我放整个代码的原因）

function Square(props) {
  return (
    <button className="square" onClick={props.onClick}>
      {props.value}
    </button>
  );
}

function calculateWinner(squares) {
  const lines = [
    [0, 1, 2],
    [3, 4, 5],
    [6, 7, 8],
    [0, 3, 6],
    [1, 4, 7],
    [2, 5, 8],
    [0, 4, 8],
    [2, 4, 6],
  ];
  for (let i = 0; i < lines.length; i++) {
    const [a, b, c] = lines[i];
    if (squares[a] && squares[a] === squares[b] && squares[a] === squares[c]) {
      return squares[a];
    }
  }
  return null;

class Board extends React.Component {
  renderSquare(i) {
    return <Square value={this.props.squares[i]} 
    onClick={()=>{this.props.onClick(i)}}/>;
  }
  
  render() {
    return (
      <div>
        <div className="board-row">
          {this.renderSquare(0)}
          {this.renderSquare(1)}
          {this.renderSquare(2)}
        </div>
        <div className="board-row">
          {this.renderSquare(3)}
          {this.renderSquare(4)}
          {this.renderSquare(5)}
        </div>
        <div className="board-row">
          {this.renderSquare(6)}
            {this.renderSquare(7)}
            {this.renderSquare(8)}
          </div>
        </div>
    );
  }
}
  
class Game extends React.Component {
  constructor(props) {
    super(props)
    this.state = {
      history: [{
        squares: Array(9).fill(null)
      }],
      stepNumber: 0,
      xIsNext: true,
      winner: null
    }
  };

  handleClick(i) {
    const history = this.state.history.slice(0, this.state.stepNumber + 1);
    const current = history[history.length - 1];
    const squares = current.squares.slice();
    if (calculateWinner(squares) || squares[i]) {
      return;
    }
    squares[i] = this.state.xIsNext ? 'X' : 'O';
    this.setState({
      history: history.concat([{
        squares: squares,
      }]),
      stepNumber: history.length,
      xIsNext: !this.state.xIsNext,
    });
  }

  jumpTo(step) {
    this.setState({
      stepNumber: step,
      xIsNext: (step % 2) === 0,
    });
  }
  
  checkForWinner(squares,winr) {
    if (winr === null)
      this.setState({
        winner: calculateWinner(squares)
      })
  }
  
  render() {
    const history = this.state.history;
    const current = history[this.state.stepNumber];
    const winner = this.state.winner

    const moves = history.map((_, move) => {
      const desc = move ?
        'Go to move #' + move :
        'Go to game start';
      return (
        <li key={move}>
          <button onClick={() => this.jumpTo(move)}>{desc}</button>
        </li>
      );
    });

    return (
      <div className="game">
        <div className="game-board">
          <Board
            squares={current.squares}
            onClick={i => {
              if (!winner) {
                this.handleClick(i)
              }
              this.checkForWinner(current.squares, winner)
            }}
            
          />
        </div>
        <div className="game-info">
          <div>{(winner) ? 'Winner: ' + winner : 'Next player: ' + (this.state.xIsNext ? 'X' : 'O')}</div>
          <ol>{(winner) ? moves : null}</ol>
        </div>
      </div>
    );
  }
}
 
ReactDOM.render(
  <Game />,
  document.getElementById('root')
);

Answer 1

当您检查获胜者而应该是获胜者时，方块仍未更新（this.handleClick 确实更改了状态，但更改本身是异步的）。

我建议将获胜者支票移到点击处理程序中

handleClick(i) {
  const history = this.state.history.slice(0, this.state.stepNumber + 1);
  const current = history[history.length - 1];
  const squares = current.squares.slice();
  if (squares[i]) {
    return;
  }
  squares[i] = this.state.xIsNext ? "X" : "O";
  this.setState({
    history: history.concat([
      {
        squares: squares
      }
    ]),
    stepNumber: history.length,
    xIsNext: !this.state.xIsNext,
    winner: calculateWinner(squares) // <-- this
  });
}

https://codesandbox.io/s/epic-sutherland-gj6d5?file=/src/App.js:1996-2028