返回枚举 ivar 会导致 EXC_BAD_ACCESS

Question

我正在编写一个游戏，其中 MainGameplay 类通过将 ivar 设置为枚举值来跟踪轮到谁：

typedef enum {
  GAME_NOT_STARTED,
  PLAYER_1_TO_MOVE,
  PLAYER_2_TO_MOVE
} WhoseTurnIsIt;

然后 GameBoard 类检查移动尝试是否有效，并调用 turnEnded:(WhoseTurnIsIt)turn 或 MainGameplay.m 中的 reportTurnFailure:(WhoseTurnIsIt)turn。

当我尝试在 MainGameplay 的接收方法中访问此返回值时，我会立即收到 EXC_BAD_ACCESS。看来我应该保留一些东西，但你不能保留枚举。在调试器中，值就在那里，所以我不明白哪些内容被错误访问。

这是在 GameBoard 中执行调用的代码：

-(void)buttonPressed:(id)sender {
  CCArray *kids = [[[CCDirector sharedDirector] runningScene] children];
  if (!mainScene) { // mainScene is an ivar on each the GameBoard's buttons.
    for (CCScene *s in kids) {
      // this looks crazy because the "main" scene is actually a controlling layer that has as a child the main gameplay layer:
      if ([s isKindOfClass:[ControlLayer class]]) {
        self->mainScene = (MainGameplay *)((ControlLayer *) s).gameLayer;
      }
    }
  }

  if (MOVE_NO_ERROR == [self checkMove:mainScene.turn]) {
    [self setMove:mainScene.turn];
    [mainScene turnEnded:mainScene.turn]; // This line and the next are the ones causing the EXC_BAD_ACCESS
  } else [mainScene reportTurnFailure:mainScene.turn]; // This line too.
}

编辑 mainScene 中的函数被调用如下：

-(void) reportTurnFailure:(WhoseTurnIsIt)_turn {
  NSLog(@"MainScene still valid"); // This line works fine
  NSLog(@"Bzzzzzt. Player %@, try again", _turn); // This line crashes BUT _turn shows up with a proper value in the debugger.
}

Answer 1

_turn 不是对象，但 %@ 格式说明符表示参数是对象。请改用%i。

-(void) reportTurnFailure:(WhoseTurnIsIt)_turn {
  NSLog(@"MainScene still valid"); // This line works fine
  NSLog(@"Bzzzzzt. Player %i, try again", _turn); // This line crashes BUT _turn shows up with a proper value in the debugger.
}