在iOS开发中经常使用到NSTimer，我们都知道NSTimer会对target retain一次，导致相互强引用target无法释放。我们可以消息转发代理NSProxy来解决NSTimer内存泄漏问题。
具体代码如下：
#import <Foundation/Foundation.h>
@interface TTWeakProxy : NSProxy
+ (instancetype)weakProxyWithTarget:(id)target;
@end
#import "TTWeakProxy.h"
@interface TTWeakProxy ()
@property (nonatomic, weak) id target;
@end
@implementation TTWeakProxy
+ (instancetype)weakProxyWithTarget:(id)target
{
TTWeakProxy *weakProxy = [TTWeakProxy alloc];
weakProxy.target = target;
return weakProxy;
}
- (id)forwardingTargetForSelector:(SEL)selector {
return _target;
}
- (void)forwardInvocation:(NSInvocation *)invocation
{
void *nullPointer = NULL;
[invocation setReturnValue:&nullPointer];
}
- (NSMethodSignature *)methodSignatureForSelector:(SEL)sel
{
return [NSObject instanceMethodSignatureForSelector:@selector(init)];
}
@end
PS: 要记得在dealloc调用NSTimer的invalidate方法，把定时器从run loop中移除。
