修复警告“在该块中强烈捕获[对象]可能导致保留周期”在启用ARC的代码中

本文介绍了修复警告“在该块中强烈捕获[对象]可能导致保留周期”在启用ARC的代码中的处理方法，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！ 我对文档的理解说，在块中使用关键字 block 后将变量设置为nil应该可以，但它仍然显示警告。 __ block ASIHTTPRequest * request = [[ASIHTTPRequest alloc] initWithURL：... [request setCompletionBlock：^ { NSDictionary * jsonDictionary = [[CJSONDeserializer deserializer] deserialize：request.responseData error：nil]; request = nil; // .... }]; 更新：使用关键字'_ _block'，并使用一个临时变量： ASIHTTPRequest * _request = [[ASIHTTPRequest alloc ] initWithURL：... __weak ASIHTTPRequest * request = _request; [request setCompletionBlock：^ { NSDictionary * jsonDictionary = [[CJSONDeserializer deserializer] deserialize：request.responseData error：nil]; // ... }]; 如果您还要定位iOS 4，请使用 __ unsafe_unretained ，而不是 __ weak 。同样的行为，但指针保持悬挂，而不是当对象被销毁时自动设置为nil。 In ARC enabled code, how to fix a warning about a potential retain cycle, when using a block-based API?The warning:Capturing 'request' strongly in this block is likely to lead to a retain cycleproduced by this snippet of code: ASIHTTPRequest *request = [[ASIHTTPRequest alloc] initWithURL:...[request setCompletionBlock:^{ NSDictionary *jsonDictionary = [[CJSONDeserializer deserializer] deserialize:request.rawResponseData error:nil]; // ... }];Warning is linked to the use of the object request inside the block. 解决方案 Replying to myself:My understanding of the documentation says that using keyword block and setting the variable to nil after using it inside the block should be ok, but it still shows the warning.__block ASIHTTPRequest *request = [[ASIHTTPRequest alloc] initWithURL:...[request setCompletionBlock:^{ NSDictionary *jsonDictionary = [[CJSONDeserializer deserializer] deserialize:request.responseData error:nil]; request = nil;// .... }];Update: got it to work with the keyword '_weak' instead of '_block', and using a temporary variable:ASIHTTPRequest *_request = [[ASIHTTPRequest alloc] initWithURL:...__weak ASIHTTPRequest *request = _request;[request setCompletionBlock:^{ NSDictionary *jsonDictionary = [[CJSONDeserializer deserializer] deserialize:request.responseData error:nil]; // ... }];If you want to also target iOS 4, use __unsafe_unretained instead of __weak. Same behavior, but the pointer stays dangling instead of being automatically set to nil when the object is destroyed. 这篇关于修复警告“在该块中强烈捕获[对象]可能导致保留周期”在启用ARC的代码中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！