creating an object and setting a retaining property

Question

How should I set a retained property when creating an object using alloc and init? (Without using autorelease)

With this line in the header (and the corresponding @synthesize line in the implementation):

@property(retain)UIWebView *webView;

These are the three options I have (I think):

---

UIWebView *tempWebView = [[UIWebView alloc] init];
[tempWebView setDelegate:self];
tempWebView.hidden = YES;
self.webView = tempWebView;
[tempWebView release];

(This one seems the best concerning memory management but it's more lines of code and involves a stupid variable name, so a decrease in readability)

---

self.webView = [[UIWebView alloc] init];
[self.webView release];
[self.webView setDelegate:self];
self.webView.hidden = YES;

(This one it's more obvious whats happening but the memory management doesn't seem that great, also Xcode's Analyser doesn't like it)

---

webView = [[UIWebView alloc] init];
[self.webView setDelegate:self];
self.webView.hidden = YES;

(This one is the shortest, it's more obvious than the first example whats happening. But it bypasses the setter, so should a custom implementation of the setter be implemented later it won't work in this case)

---

So which example should be used, or is there a better way?

Answer 1

The best option, IMO, is the one you don't like, i.e. using autorelease:

 self.webView = [[[UIWebView alloc] init] autorelease];

If you do not want to and want a one-liner initialization, the only option is your third one:

 webView = [[UIWebView alloc] init];

since all the others requires an explicit line to do an extra release.

I don't see it as bad, especially when it belongs to the init method and you don't reassign it elsewhere without using the property, and I myself use it when it seems reasonable to me.

What works really well with retained properties are convenience constructors like:

self.image = [UIImage imageWithContentsOfFile:xxxxxxx];

So, possibly if you really find that none of the options you listed is fine with you, you might add a category to UIWebView and a convenience constructor doing the autorelease job for you:

self.webView = [UIWebView webViewWith......];