Objective C 实例变量尽管被保留但仍被释放

发布于 2024-11-24 16:03:01 字数 833 浏览 5 评论 0原文

我有一个棉花糖类，它（除其他外）有一个 CCSprite 对象作为实例变量。

这是 init 方法：

-(id) init
{
    if((self = [super init]))
    {   
        model = [[CCSprite spriteWithFile:@"marshmallow.png"] retain];
        maxSpeed = 5; //160px per second (maxspeed * PTM_Ratio = px/second max)
        gravity = 9.81; // in meters/sec^2
        health = 3;
    }

    return self;
}

该变量在另一个文件中声明为全局变量，并使用以下行：

Marshmallow *mainChar;

稍后在文件中，使用此行设置（初始化/分配）：

mainChar = [[mainChar alloc] init];

在编写上一行时，xcode 给了我一个警告 Marshmallow 可能不会响应分配。（我不认为这是相关的。只是提到任何看起来错误的东西）

我的问题是以下代码行返回 nil：

[mainChar getModel];

为什么它返回 nil 而不是实例变量？

这是 getModel 函数：

-(CCSprite *)getModel
{
    return model;
}

原文

I have a marshmallow class which has (among other things) a CCSprite object as an instance variable.

here is the init method:

-(id) init
{
    if((self = [super init]))
    {   
        model = [[CCSprite spriteWithFile:@"marshmallow.png"] retain];
        maxSpeed = 5; //160px per second (maxspeed * PTM_Ratio = px/second max)
        gravity = 9.81; // in meters/sec^2
        health = 3;
    }

    return self;
}

the variable is declared in another file as a global variable with the line:

Marshmallow *mainChar;

Later in the file, it is set (initiated/alloc'd) with this line:

mainChar = [[mainChar alloc] init];

while writing the previous line, xcode gave me a warning that Marshmallow might not respond to alloc. (I don't think that's related. just mentioning anything that seems wrong)

my problem is that the following line of code returns nil:

[mainChar getModel];

why does it return nil instead of the instance variable?

here is the getModel function:

-(CCSprite *)getModel
{
    return model;
}

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

堇色安年 2024-12-01 16:03:01

mainChar = [[mainChar alloc] init];

不应该吗

mainChar = [[Marshmallow alloc] init];

？

该消息表示该类的对象可能不会响应它，而不是类本身。

mainChar = [[mainChar alloc] init];

Shouldn't be

mainChar = [[Marshmallow alloc] init];

The message says an object from that class might not respond to it, not the class itself.

回复收藏 0 原文

时间海 2024-12-01 16:03:01

您的问题在于 mainChar 变量的初始化。您要查找的行是这样的：

mainChar = [[mainChar alloc] init];

您收到的警告告诉您 Marshmallow 类型的实例将不会响应 -alloc 消息。这就是你的问题：你想调用 +alloc 类方法，如下所示：

mainChar = [[Marshmallow alloc] init];

Your problem is in the initialization of your mainChar variable. The line you're looking for is this:

mainChar = [[mainChar alloc] init];

The warning you got is telling you that instances of type Marshmallow will not respond to the -alloc message. That is your problem: you want to call the +alloc class method instead, like so: