重新分配变量不起作用

Question

我有一个令人困惑的问题 - 它似乎应该很容易做，但不知何故它不工作。我有一个叫做Player的对象。 Manager类有四个播放器实例：

@interface Manager 
{ 
    Player *p1, *p2, *mCurrentPlayer, *mCurrentOpponent; 
} 
// @property... 

Manager对象具有initPlayers和swapPlayers方法。

-(void) initPlayers { // this works fine 
    self.p1 = [[Player alloc] init]; 
    self.p2 = [[Player alloc] init]; 
    self.mCurrentPlayer = self.p1; 
    self.mCurrentOpponent = self.p2; 
} 

-(void) swapPlayers { // this swapping of pointer doesn't work 
    self.mCurrentPlayer = self.p2; 
    self.mCurrentOpponent = self.p1; 

    // When I look at the pointer in debugger, self.mCurrentPlayer is still self.p1. :-(

    // I even tried first setting them to nil, 
    // or first releasing them (with an extra retain on assignment) to no avail 
} 

我在想什么？提前致谢！

Answer 1

不知道您的访问器是如何设置的，将难以按原样对代码进行故障排除。话虽这么说，这里是如何您存取和代码应设置：

Manager.h

@interface Manager 
{ 
    Player *p1, *p2, *mCurrentPlayer, *mCurrentOpponent; 
} 
@property (nonatomic, retain) Player *p1; 
@property (nonatomic, retain) Player *p2; 
@property (nonatomic, assign) Player *mCurrentPlayer; 
@property (nonatomic, assign) Player *mCurrentOpponent; 
@end 

Manager.m

-(void) initPlayers { 
    self.p1 = [[[Player alloc] init] autorelease]; 
    self.p2 = [[[Player alloc] init] autorelease]; 
    self.mCurrentPlayer = self.p1; 
    self.mCurrentOpponent = self.p2; 
} 

-(void) swapPlayers { 
    Player * temp = self.mCurrentPlayer; 
    self.mCurrentPlayer = self.mCurrentOpponent; 
    self.mCurrentOpponent = temp; 
} 

Answer 2

事实证明这个问题在代码中无关，我误解了问题的症状！但为了讨论的缘故，为什么需要在多行上使用@property，并使用临时变量交换玩家（按照e.James的答案）？