nsobject

NSObject +load and +initialize - What do they do?

由 戏子无情 提交于 2019-11-26 16:54:00
I'm interested in understanding the circumstances leading a developer to override +initialize or +load. Documentation makes it clear these methods are called for you by the Objective-C runtime, but that's really all that is clear from the documentation of those methods. :-) My curiosity comes from looking at Apple's example code - MVCNetworking. Their model class has a +(void) applicationStartup method. It does some housekeeping on the filesystem, reads NSDefaults, etc etc... and, after trying to grok NSObject's class methods, it seems like this janitorial work might be okay to put into +load.

How do copy for UILabel?

由 偶尔善良 提交于 2019-11-26 16:35:38
问题 I have IBOutlet UILabel *label; and I want to do this UILabel *label = [titleLabel copy]; label.text = @"Clone"; titleLabel.text = @"Original"; NSLog(@"label : %@, title : %@",label.text,titleLabel.text); and this throw exception * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UILabel copyWithZone:]: unrecognized selector sent to instance 0x6a4a450' * First throw call stack: (0x126f052 0x1823d0a 0x1270ced 0x11d5f00 0x11d5ce2 0x1271bd9 0x2ed6 0x1270e1a

What is __NSArrayI and __NSArrayM? How to convert to NSArray?

由 主宰稳场 提交于 2019-11-26 15:52:59
问题 What is __NSArrayI and __NSArrayM? __NSArrayI(or M) cause "unrecognized selector" error. How to convert to NSArray? I did test to parse json, twitter api. http://api.twitter.com/1/followers/ids.json?cursor=-1&screen_name=twitterapi ==> works fine. parsed object is NSCFDictionary class. (This dictionary contains __NSArrayM class) http://api.twitter.com/1/statuses/user_timeline.json?&screen_name=twitterapi ==> error. parsed object is __NSArrayM class. 回答1: __NSArrayI is a code-word for an

Removing Duplicates From Array of Custom Objects Swift

由 穿精又带淫゛_ 提交于 2019-11-26 11:24:18
问题 I have a custom class defined as follows : class DisplayMessage : NSObject { var id : String? var partner_image : UIImage? var partner_name : String? var last_message : String? var date : NSDate? } Now I have an array myChats = [DisplayMessage]? . The id field is unique for each DisplayMessage object. I need to check my array and remove all duplicates from it, essentially ensure that all objects in the array have a unique id . I have seen some solutions using NSMutableArray and Equatable

NSObject +load and +initialize - What do they do?

由 戏子无情 提交于 2019-11-26 06:04:18
问题 I\'m interested in understanding the circumstances leading a developer to override +initialize or +load. Documentation makes it clear these methods are called for you by the Objective-C runtime, but that\'s really all that is clear from the documentation of those methods. :-) My curiosity comes from looking at Apple\'s example code - MVCNetworking. Their model class has a +(void) applicationStartup method. It does some housekeeping on the filesystem, reads NSDefaults, etc etc... and, after
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