2015年5月6日
创建自己的NSError对象
摘要： Generating Your Own ErrorsIn order to create your own NSError objects you’ll need to define your own error domain, which should be of the form:com.com... 阅读全文
posted @ 2015-05-06 17:24 huang303513 阅读(1377) 评论(0) 推荐(0)
block作为函数参数回调
摘要： Blocks make this much easier, however, because you can define the callback behavior at the time you initiate the task, like this:- (IBAction)fetchRemo... 阅读全文
posted @ 2015-05-06 16:11 huang303513 阅读(451) 评论(0) 推荐(0)
NSNull的用法和原理
摘要： Represent nil with NSNullIt’s not possible to add nil to the collection classes described in this section because nil in Objective-C means “no object.... 阅读全文
posted @ 2015-05-06 13:21 huang303513 阅读(493) 评论(0) 推荐(0)