This is a fairly complicated inheritance hierarchy, so bear with me (I’ve tried to simplify things rather than state the exact case I am using which is even more complex):-<\/p>\n
Let’s say I create a subclass of However, in turn, I want to make it so that I hope you’re still with me, because I haven’t done anything too complex so far. But let’s say that now, I create another custom subclass of Let’s also assume that I want to make it so that The problem is: how do I do implement this in Inheritance<\/strong><\/p>\n I cannot simply inherit the delegate from Overriding ivar<\/strong><\/p>\n I could try declaring an ivar in Modifying the superclass<\/strong><\/p>\n I could go back to the I haven’t tried this one, simply because it seems to break every sensible coding rule in the book.<\/p>\n In summary, there must be some way of doing this such that a subclass of a class can have it’s own delegate that’s a sub-delegate of the superclass’s delegate and for all of this to fit together nicely, but I just can’t figure it out! Any ideas?<\/p>\n (* As a side issue, I don’t understand why the compiler complains when This is a fairly complicated inheritance hierarchy, so bear with me (I’ve tried to simplify things rather than state the exact case I am using which is even more complex):- Let’s say I create a subclass of UITextField called TextField which is my own custom enhanced general-purpose textfield. Now, in order to provide this enhanced […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-4966","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/4966","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/comments?post=4966"}],"version-history":[{"count":0,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/4966\/revisions"}],"wp:attachment":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/media?parent=4966"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/categories?post=4966"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/tags?post=4966"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}UITextField<\/code> called TextField<\/code> which is my own custom enhanced general-purpose textfield. Now, in order to provide this enhanced functionality, in the init<\/code> method of TextField<\/code>, I set super.delegate = self<\/code> so that all the delegate methods from UITextField<\/code> are sent to TextField<\/code>. TextField<\/code> implements the UITextFieldDelegate<\/code> protocol and receives those delegate methods to do something interesting.<\/p>\nTextField<\/code> has it’s own<\/em> delegate. So I create a new protocol called TextFieldDelegate<\/code> (note the lack of UI<\/code>-prefix!) and give TextField<\/code> an ivar id __weak delegate<\/code> with corresponding property so that other classes can receive delegate methods from TextField<\/code>.<\/p>\nTextField<\/code>, let’s call it PasswordTextField<\/code> (in real life, one probably wouldn’t need to create a subclass just to implement a password functionality, but let’s assume that there is some fairly sophisticated implementation that would require this).<\/p>\nPasswordTextField<\/code> (which like TextField<\/code> has a delegate property) is able to send an enhanced set of delegate methods. For example, maybe it can send a method passwordIsSecure<\/code> which is sent once a password has reached a required level of complexity. Now since this behaviour that wouldn’t be found in the regular TextField<\/code>, I create a new protocol: PasswordTextFieldDelegate<\/code> which defines the new delegate methods for PasswordTextField<\/code> and<\/em> inherits all of the delegate methods sent by TextField<\/code>.<\/p>\nPasswordTextField<\/code>? Things that don’t work:<\/p>\nTextField<\/code>, because TextField<\/code>‘s delegate conforms only to TextFieldDelegate<\/code> and not PasswordTextFieldDelegate<\/code>, so I can’t send methods like [delegate passwordIsSecure]<\/code> because TextFieldDelegate<\/code> has no such method.<\/p>\nPasswordTextField<\/code> called delegate, but the compiler complains that this is a duplicate declaration, because of course there is already an ivar called delegate in the superclass, so this doesn’t work either*.<\/p>\nTextField<\/code> class and redefine the delegate to implement both TextFieldDelegate<\/code> and<\/strong> PasswordTextFieldDelegate<\/code>, but this seems messy and tells TextField<\/code> that it can send PasswordTextFieldDelegate<\/code> methods, which of course, it can’t!<\/p>\nPasswordTextField<\/code> declares a “duplicate” ivar named delegate, but doesn’t complain when TextField<\/code> declares an ivar named delegate which is presumably a duplicate of UITextField<\/code>‘s property called delegate!)<\/p>\n","protected":false},"excerpt":{"rendered":"