javascript - react native : setState did not update immediately

Question

我正在尝试为 Android 应用程序制作 TicTacToe 游戏。我打算做的井字游戏的游戏模式是人机对战。但问题是程序没有更新我的 switchPlayer 函数中的切换过程 (setState)，因为执行 setState 后，前一个播放器和当前播放器是相同的。 switchPlayer 函数的预期输出:前一个玩家:1，当前玩家:-1 但实际输出:前一个玩家:1，当前玩家:1。

我也尝试使用其他 Stackoverflow 问题建议/推荐的回调方法，但仍然无法正常工作。我做对了吗？任何建议将不胜感激。提前谢谢你。

代码如下:

switchPlayer = (newPlayer) => {
   console.log("Previous player: "+this.state.currentPlayer);
   this.setState(

   {currentPlayer: newPlayer},
   function () {console.log("Current player: "+this.state.currentPlayer); }

   );
};

onTilePress = (row, col, ValidMove) => {

   if (ValidMove == 1) {  //If move is valid

       //Dont allow tiles to change
       var value = this.state.gameState[row][col];
       if (value !== 0) { return;}

       //Identify and grab current player
       var PlayerNow = this.state.currentPlayer;   

       console.log(row, col, PlayerNow);
       //Set the correct tile...
       var arr = this.state.gameState.slice();
       arr[row][col] = PlayerNow;
       this.setState({gameState: arr});

       //Switch to other player
       if (PlayerNow == 1) { //if player 1, then change to bot
           this.switchPlayer(-1);
       }            
       else if (PlayerNow == -1) {
           this.switchPlayer(1);
       }

       console.log("New current player " + this.state.currentPlayer);

       //check winner
       var winner = this.getWinner();  //get the winner update
       if (winner == 1) {
          Alert.alert("Player 1 has won!");
          this.initializeGame();
       }
       else if (winner == -1){
          Alert.alert("Bot has won!");
          this.initializeGame();
       }
       else if (this.checkTie() == 9){ //check if the match is a draw
          Alert.alert("It's a draw!");
          this.initializeGame();
       }
       //Alert.alert("It's Player "+takePlayer+"'s turn!");
       this.BotMove();
   }
   else {
       Alert.alert("Player 1, please make a move!");
   }

}

Answer 1

如果您的问题是您希望在调用 switchPlayer() 之后的日志语句已经包含状态更改...那么您必须在调用 switchPlayer< 之后放置所有内容 在已通过 switchPlayer

传播的回调中

switchPlayer = (newPlayer, cb) => {
   console.log("Previous player: "+this.state.currentPlayer);
   this.setState(
       {currentPlayer: newPlayer},
       function () { 
          console.log("Current player: "+this.state.currentPlayer);
          // Callers should put their code 
          if (cb) {
              cb();
          }
       }
   );
};

onTilePress = (row, col, ValidMove) => {
       // Switch to other player
       if (PlayerNow == 1) { //if player 1, then change to bot
           this.switchPlayer(-1, () => {
                // Here, you know the state has been updated
            });
       }            
       else if (PlayerNow == -1) {
             ....
       }
       // This code executes before the state is changed, you get the old state
       // All your code should really be in the callbacks to `switchPlayer`
       // or to any method that calls `setState`
       console.log("New current player " + this.state.currentPlayer);
       ...
}