本文介绍了NSTimer类别+阻止实现替换选择器的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 29岁程序员，3月因学历无情被辞！ 我对块和objective-c很新，我正在尝试用两者编写我的第一个类别。我的想法是在NSTimer上创建一个类别，它将接收一个块作为参数，这个块将用于选择器调用。现在我有这个。I am quite new to blocks and objective-c, and i am trying to write my first category using both. My idea is to create a category on NSTimer that will receive a block as a parameter and this block will be used in the selector call. Right now I have this.// NSTimer+Additions.h#import <Foundation/Foundation.h>typedef void (^VoidBlock)();@interface NSTimer (NSTimer_Additions)+ (NSTimer *)scheduleTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions;@end#import "NSTimer+Additions.h"static VoidBlock _voidBlock;@interface NSTimer (AdditionsPrivate) // Private stuff- (void)theBlock;@end@implementation NSTimer (NSTimer_Additions)+ (NSTimer *)scheduleTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions { [_voidBlock release]; _voidBlock = [actions copy]; NSTimer* timer = [[NSTimer alloc] initWithFireDate:[NSDate date] interval:theSeconds target:self selector:@selector(theBlock) userInfo:nil repeats:repeats]; [timer fire]; return [timer autorelease];}- (void)theBlock { _voidBlock();}@end代码的要点： https://gist.github.com/1065235一切都编译好但我有以下错误：Everything compiles fine but i have the following error: 2011-07-05 14：35：47.068 TesteTimer [37716：903] * 由于未捕获的异常'NSInvalidArgumentException'终止应用程序，原因：'+ [NSTimer theBlock]：无法识别的选择器发送到类0x7fff70bb0a18'2011-07-05 14:35:47.068 TesteTimer[37716:903] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[NSTimer theBlock]: unrecognized selector sent to class 0x7fff70bb0a18'如何使此类别有效？推荐答案除了错误的目标之外，你的主要缺陷是使用静态变量。除了单个计时器之外，您将无法支持。Your major flaw besides the wrong target is your use of a static variable. You won't be able to support beyond a single timer.@interface NSTimer (AdditionsPrivate) // Private stuff- (void)theBlock:(VoidBlock)voidBlock;@end@implementation NSTimer (NSTimer_Additions)+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions { NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:[self instanceMethodSignatureForSelector:@selector(theBlock:)]]; NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:theSeconds invocation:invocation repeats:repeats]; [invocation setTarget:timer]; [invocation setSelector:@selector(theBlock:)]; Block_copy(actions); [invocation setArgument:&actions atIndex:2]; Block_release(actions); return timer;}- (void)theBlock:(VoidBlock)voidBlock { voidBlock();}@end使用关联参考的问题泄漏是因为没有好处释放该区块。The problem with using associative references was the leak as there was no good point to release the block.您可以使用 关联引用 将块附加到的特定实例的NSTimer 。@implementation NSTimer (NSTimer_Additions)+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions { NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:[self instanceMethodSignatureForSelector:@selector(theBlock)]]; NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:theSeconds invocation:invocation repeats:repeats]; [invocation setTarget:timer]; [invocation setSelector:@selector(theBlock)]; objc_setAssociatedObject(timer, @"Block", actions, OBJC_ASSOCIATION_COPY); return timer;}- (void)theBlock { VoidBlock _voidBlock = (VoidBlock)objc_getAssociatedObject(self, @"Block"); _voidBlock();}@end 这篇关于NSTimer类别+阻止实现替换选择器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！