Objective c 从其他类检索变量不起作用

如果我这样做，是否可以从另一个类获取变量：

----------------------------HelloWorldLayer.h-------------------------------

@interface HelloWorldLayer : CCLayer
{  

...
BOOL win;
...
}

@property (nonatomic,readwrite) BOOL win;

@synthesize win;

-(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
  if (...){

  //do something with with variable win ----> IN <---- if statement
  win = YES;
  }
//win is changed only in if statement
}

-(void)nextLevel:(id)sender{
    NSLog(@"next level");

    HelloWorldLayer *obj = [[HelloWorldLayer alloc]init];
    if (obj.win==YES){
        NSLog(@"win = YES");
    }else {
        NSLog(@"win = NO");
    }
    win = NO;
    [[CCDirector sharedDirector] popScene];

}

@interface HelloWorldLayer : CCLayer

@property (nonatomic) BOOL win;

@synthesize win=_win;

-(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
  if (...){
      self.win = YES;
  }

}

----------------------------HelloWorldLayer.m-------------------------------

@interface HelloWorldLayer : CCLayer
{  

...
BOOL win;
...
}

@property (nonatomic,readwrite) BOOL win;

@synthesize win;

-(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
  if (...){

  //do something with with variable win ----> IN <---- if statement
  win = YES;
  }
//win is changed only in if statement
}

-(void)nextLevel:(id)sender{
    NSLog(@"next level");

    HelloWorldLayer *obj = [[HelloWorldLayer alloc]init];
    if (obj.win==YES){
        NSLog(@"win = YES");
    }else {
        NSLog(@"win = NO");
    }
    win = NO;
    [[CCDirector sharedDirector] popScene];

}

@interface HelloWorldLayer : CCLayer

@property (nonatomic) BOOL win;

@synthesize win=_win;

-(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
  if (...){
      self.win = YES;
  }

}

我是否可以首先在此处获取并设置变量

win

，以便另一个类现在已将win变量分配给

NO

，或者if语句中的win赋值是否未全局处理

---

如果我在

init

方法中指定变量

NO

，并在函数中更改它，它将只接受在

init

方法中指定的值。。。为什么会这样？

你想考虑使用一个协议。这样，无论HelloWorldLayer是否获胜，都会通知LevelDone。特别是如果HelloWorldLayer是一个长进程并且异步运行的话。下面是一个粗略的例子：

HelloWorldLayer.h

@protocol HelloWorldLayerDelegate
- (void)helloWorldLayer:(HelloWorldLayer *)layer didWin:(BOOL)win;
@end

@interface HelloWorldLayer : CCLayer
{  

...
BOOL win;
...
}

@property (nonatomic,readwrite) BOOL win;
@property (nonatomic, assign) id <HelloWorldLayerDelegate>delegate;

@end

@interface LevelDone <HelloWorldLayerDelegate>
    HelloWorldLayer *_hello;
@end

---

这是一个混淆使用@synthesis生成的访问器和直接引用实例变量的例子。尝试如下方式声明您的属性：

----------------------------HelloWorldLayer.h-------------------------------

@interface HelloWorldLayer : CCLayer
{  

...
BOOL win;
...
}

@property (nonatomic,readwrite) BOOL win;

@synthesize win;

-(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
  if (...){

  //do something with with variable win ----> IN <---- if statement
  win = YES;
  }
//win is changed only in if statement
}

-(void)nextLevel:(id)sender{
    NSLog(@"next level");

    HelloWorldLayer *obj = [[HelloWorldLayer alloc]init];
    if (obj.win==YES){
        NSLog(@"win = YES");
    }else {
        NSLog(@"win = NO");
    }
    win = NO;
    [[CCDirector sharedDirector] popScene];

}

@interface HelloWorldLayer : CCLayer

@property (nonatomic) BOOL win;

@synthesize win=_win;

-(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
  if (...){
      self.win = YES;
  }

}

----------------------------HelloWorldLayer.m-------------------------------

@interface HelloWorldLayer : CCLayer
{  

...
BOOL win;
...
}

@property (nonatomic,readwrite) BOOL win;

@synthesize win;

-(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
  if (...){

  //do something with with variable win ----> IN <---- if statement
  win = YES;
  }
//win is changed only in if statement
}

-(void)nextLevel:(id)sender{
    NSLog(@"next level");

    HelloWorldLayer *obj = [[HelloWorldLayer alloc]init];
    if (obj.win==YES){
        NSLog(@"win = YES");
    }else {
        NSLog(@"win = NO");
    }
    win = NO;
    [[CCDirector sharedDirector] popScene];

}

@interface HelloWorldLayer : CCLayer

@property (nonatomic) BOOL win;

@synthesize win=_win;

-(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
  if (...){
      self.win = YES;
  }

}

我认为BOOL值总是默认为False，因此您实际上不需要在init（）中设置它，除非您希望它默认为True

无论如何，现在实例变量在类HelloWorldLayer中设置为_win。无论何时您想要设置它，请始终将其称为self.win。在处理属性时，这是一个安全的习惯，以确保不会遇到内存泄漏，因为在处理指针时，生成的访问器将为您释放和保留。如果直接设置实例变量，则必须记住首先释放它

希望这有帮助

如果我在init方法中指定变量NO并在 函数，它将只接受在 初始化方法。。。这到底是为什么

因为您没有使用相同的对象，所以您正在创建一个新对象：

HelloWorldLayer *obj = [[HelloWorldLayer alloc]init];
    if (obj.win==YES){
        NSLog(@"win = YES");
    }else {
        NSLog(@"win = NO");
    }

每次运行这行代码时：

HelloWorldLayer *obj = [[HelloWorldLayer alloc]init];

…创建HelloWorldLayer的新实例。它将运行init方法中的代码，因为您正在向它发送

init

消息。这就是为什么上面的代码将记录在init方法中设置的任何值

---

您想要的是访问HelloWorldLayer的现有实例，而不是创建该类的新实例。我相信@Jeremy已经为您提供了一个令人满意的解决方案。另一种方法是将HelloWorldLayer类转换为单例。

好的，非常感谢。。。一个问题：如果我把

@protocol HelloWorldLayerDelegate-（void）helloWorldLayer:（helloWorldLayer*）层放到didWin:（BOOL）win在
@界面之前
它将无法识别类型
（HelloWorldLayer*）
谢谢。我以前就想到过，但我（错误地）被告知我实际上可以访问它们。