在ARC中使用“context”变量的beginAnimations？(beginAnimations with “context”variable in ARC?)

在ARC中使用“context”变量的beginAnimations？(beginAnimations with “context”variable in ARC?)

这个问题与现有问题部分类似，但我仍然会遇到内存管理错误。

以下非ARC代码有效：

[UIView beginAnimations:... context:[[NSNumber numberWithInt:i] retain]];

和didStopSelector中的某个地方：

NSNumber * n = (NSNumber *)context; ... [n release];

我试图删除保留/释放并添加副本（并结合这些方式）但没有效果。

另外我看到另一个类似的问题：

在ARC中的多个UIImageViews上的UIView动画

它们将imageName变量作为context传递，但它们不描述它是保留还是自动释放。

问题：

1）如何正确地将我的代码转换为ARC？

2）如果你传递保留/自动释放的上下文（cousre，如果自动释放将在一般情况下工作），代码是否有任何区别？

The question partially similar to existing ones but I still get error with memory management.

The following non-ARC code work:

[UIView beginAnimations:... context:[[NSNumber numberWithInt:i] retain]];

and somewhere in didStopSelector:

NSNumber * n = (NSNumber *)context; ... [n release];

I tried to remove retain/release and to add copy (and combined these ways) but with no effect.

Additionally I saw another similar question:

UIView Animation on multiple UIImageViews in ARC

They pass imageName variable as context but they don't describe if it is retained or autoreleased.

Questions:

1)How to convert my code to ARC correctly?

2)Is there any difference in code if you pass retained/autoreleased context (of cousre, if autoreleased will work in general)?

最满意答案

尝试使用__bridge_retained来保留对象并将其__bridge_retained转换为void*

void *context = (__bridge_retained void *)( @1000 );

然后在animationDidStop您必须使用__bridge_transfer转移所有权。 此时ARC应该自然地释放当前自动释放池中的对象。

- (void)animationDidStop:(void *)context { NSNumber *n = (__bridge_transfer id)context; }

或者，您可以直接切换到基于块的API和引用视图。

Try __bridge_retained to retain object and cast it to void*

void *context = (__bridge_retained void *)( @1000 );

and then in animationDidStop you have to transfer ownership with __bridge_transfer. At this point ARC should naturally release the object in current autorelease pool.

- (void)animationDidStop:(void *)context { NSNumber *n = (__bridge_transfer id)context; }

Alternatively you can switch to block based API and reference views directly.