尝试保存到 NSUserDefaults 时崩溃

Question

当我尝试将当前级别计数保存到 applicationWillTerminate 函数中的 NSUserDefaults 时，它崩溃了。为什么 ？

----------------------- AppDelegate.m -----------------------

        - (void)applicationWillTerminate:(UIApplication *)application {
            CCDirector *director = [CCDirector sharedDirector];

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

            NSNumber *lCount = [NSNumber numberWithInt:hWClass -> level];

            hWClass -> lvlCount =[NSUserDefaults standardUserDefaults];
            [hWClass -> lvlCount setObject:lCount  forKey:@"levelCount"];



            [[director openGLView] removeFromSuperview];

            [viewController release];

            [window release];

            [director end]; 
        }

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

        ...{
        @public
        int level;
        NSUserDefaults *lvlCount;
        int health;
        ...
        }
        @property (nonatomic,retain) NSUserDefaults *lvlCount;

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

  NSNumber *currentLevel = [[NSUserDefaults standardUserDefaults] objectForKey:@"levelCount"];
        if (currentLevel != nil){
        int cLevel = [currentLevel integerValue];

        [self generateLevelFromPlist:cLevel];
        }else{
            [self generateLevelFromPlist:1];
        }

Answer 1

您可以使用 -> 直接访问实例变量，然后为其分配一个自动释放的值。您需要使用点语法访问该属性才能正确保留它。

   hWClass.lvlCount =[NSUserDefaults standardUserDefaults];
   [hWClass.lvlCount setObject:lCount  forKey:@"levelCount"];

另外，通过删除 @public 或将其更改为 @private 将以下变量声明更改为私有，这样您就不会再遇到该问题了。

    ...{
    @private
    int level;
    NSUserDefaults *lvlCount;
    int health;
    ...
    }