与NSInvocation的主线程执行选择 [英] Performing selectors on main thread with NSInvocation

问题描述

我想在主线程（原因UIKit的对象不是线程安全的）执行动画，但是prepare它在一些单独的线程。我有（baAnimation - 是CABasicAnimation分配和放大器;前inited）：

I want to perform animation on main thread (cause UIKit objects are not thread-safe), but prepare it in some separate thread. I have (baAnimation - is CABasicAnimation allocated & inited before):

SEL animationSelector = @selector(addAnimation:forKey:);
NSString *keyString = @"someViewAnimation";

NSInvocation *inv = [NSInvocation invocationWithMethodSignature:[workView.layer methodSignatureForSelector:animationSelector]];
[inv setTarget:workView.layer];
[inv setSelector:animationSelector];
[inv setArgument:baAnimation atIndex:2];
[inv setArgument:keyString atIndex:3];
[inv performSelectorOnMainThread:@selector(invoke) withObject:nil waitUntilDone:NO];

我得到：

*** + NSCFString长]：无法识别的选择发送到类0x1fb36a0

*** +[NSCFString length]: unrecognized selector sent to class 0x1fb36a0

电话：

>     #0 0x020984e6 in objc_exception_throw
>     #1 0x01f7e8fb in +[NSObject doesNotRecognizeSelector:]
>     #2 0x01f15676 in ___forwarding___
>     #3 0x01ef16c2 in __forwarding_prep_0___
>     #4 0x01bb3c21 in -[CALayer addAnimation:forKey:]
>     #5 0x01ef172d in __invoking___
>     #6 0x01ef1618 in -[NSInvocation invoke]

但 [workView.layer addAnimation：baAnimation forKey：@someViewAnimation]; 工作正常。我在做什么错了？

But [workView.layer addAnimation:baAnimation forKey:@"someViewAnimation"]; works fine. What am I doing wrong?

推荐答案

在除了[INV retainArguments]（由克里斯·苏特尔提到的），你还需要传递的参数作为指针指向底层的内存。援引API：

In addition to [inv retainArguments] (as mentioned by Chris Suter) you also need to pass the arguments as pointers to the underlying memory. Citing the API:

当参数值是一个对象，传递一个指针变量（或存储器），从该物体应该被复制：

"When the argument value is an object, pass a pointer to the variable (or memory) from which the object should be copied:

NSArray *anArray;  
[invocation setArgument:&anArray atIndex:3];  

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