方法返回具有+1保留计数的Objective-C对象

Question

自从升级到Lion并因此升级到XCode 4.1

运行分析器时,我收到了数十个"潜在的内存泄漏".

我通常会使用如下属性列表:

@synthesize indexPath = _indexPath;

- (id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)nibBundle {
    self = [super initWithNibName:nibName bundle:nibBundle];
    self.indexPath = [[NSIndexPath alloc] init];
    [_indexPath release];
    return self;
}

并在dealloc()方法中:

- (void)dealloc {
    [_indexPath release];
    [super dealloc];
}

现在,分析会告诉我self.indexPath上可怕的蓝色消息,告诉我有泄漏.什么时候显然没有.

你如何分配和格式化代码,以便XCode不相信它的泄漏？(同时保留属性别名self.var vs _var)

谢谢...

Answer 1

其他答案已经深入解释了这个问题,无论如何,这些是一些可用于避免此错误的常见模式:

NSIndexPath *ip = [[NSIndexPath alloc] init];
self.indexPath = ip;
/* ... */
[ip release];

indexPath = [[NSIndexPath alloc] init];

self.indexPath = [[[NSIndexPath alloc] init] autorelease];

self.indexPath = [NSIndexPath indexPathWithIndex:...];

Answer 2

在init中你真的应该使用ivars直接设置:

- (id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)nibBundle {
    self = [super initWithNibName:nibName bundle:nibBundle];
    _indexPath = [[NSIndexPath alloc] init];
    return self;
}

也许这可以解决这个问题？它将遵循惯例.