objective-c-category

Here is my problem: I use Core Data to store rich text input from iOS and/or OS X apps and would like images pasted into the NSTextView or UITextView to: a) retain their original resolution, and b) on display to be scaled to fit the textView correctly, which means scaling based on the size of the view on the device. Currently I am using - (void)textStorage:(NSTextStorage *)textStorage didProcessEditing:(NSTextStorageEditActions)editedMask range:(NSRange)editedRange changeInLength:(NSInteger)delta to look for attachments and to then generate an image with a scale factor and assigning it to the

Can anybody tell me when to use categories and when to use subclassing in Objective-C? Also please tell me the advantages and disadvantages of them. An objective-c category is useful if you want to alter the behavior of ALL instances of the class, with minimal code. Subclassing is more useful if you want to alter the behavior of only certain instances, and retain the original method for others. Categories can be dangerous, especially if you cannot view the source of the original method, so you should generally use subclasses on third-party and private frameworks rather than a category.

Can anyone explain the differences between Protocols and Categories in Objective-C? When do you use one over the other? mipadi A protocol is the same thing as an interface in Java: it's essentially a contract that says, "Any class that implements this protocol will also implement these methods." A category, on the other hand, just binds methods to a class. For example, in Cocoa , I can create a category for NSObject that will allow me to add methods to the NSObject class (and, of course, all subclasses), even though I don't really have access to NSObject . To summarize: a protocol specifies

The NSManagedObject subclass property are created in its category file, which is very wired since category can only have method. The details are as below: (1).I have created an entity called BibleAudio in .xcdatamodeld file with several attributes as below. (2). the xcode generated objective c files are "BibleAudio + CoreDataProperties.h", "BibleAudio + CoreDataProperties.m" and "BibleAudio.h", "BibleAudio.m" as following: (3). within "BibleAudio + CoreDataProperties.h", BibleAudio's attributes are declared as property here (see following); while in "BibleAudio.h", it is empty. As far as I

I would like to add some rounded corners to all of the UIImageViews in my project. I have already got the code working, but am having to apply it to every image; should I subclass UIImageView to add this? If so, can someone give me some pointers as to how to do this? Here is the code - (void)viewDidLoad { [super viewDidLoad]; NSString *mainpath = [[NSBundle mainBundle] bundlePath]; welcomeImageView.image = [UIImage imageWithContentsOfFile:[mainpath stringByAppendingString:@"/test.png"]]; welcomeImageView.layer.cornerRadius = 9.0; welcomeImageView.layer.masksToBounds = YES; welcomeImageView

Class extensions @interface Class () are a lot more powerful and can inject variables into the class. Categories @interface Class (Category) can't. What other differences are there, and when should one use a category over a class extension? The main difference is that with an extension, the compiler will expect you to implement the methods within your main @implementation , whereas with a category you have a separate @implementation block. So you should pretty much only use an extension at the top of your main .m file (the only place you should care about ivars, incidentally) -- it's meant to