automatic-ref-counting

I would like to add a property to UITableView in a Class Extension: @interface UITableViewController () @property NSString *entityString; @end Then I import the extension and then I use entityString property in a subclass of UITableViewController: @implementation CustomerTableViewController - (void)viewDidLoad { self.entityString = @"Customer"; ... [super viewDidLoad]; } ... Apple documentation says: the compiler will automatically synthesize the relevant accessor methods (...) inside the primary class implementation. But when I try to execute it I get this error: -[CustomerTableViewController

If I declare a property like this: @property(nonatomic,weak) Foo *someProperty; and I then declare a custom setter like so: - (void)setSomeProperty:(Foo *)someProp { _someProperty = someProp; //...more custom stuff } is there anything wrong with this? That is, the compiler should automatically synthesize the _someProperty ivar with the __weak modifier, so just doing the assignment in the setter above should suffice, correct? Yes, that's all there is to it. Of course you can specify a custom iVar if you'd like something other than _someProperty like: @synthesize someProperty = someProperty_; 来源

I downloaded the Xcode 4.2 developer preview version and I created a cocoa application. But I found a very weird syntax in the delegate class: @property (strong) IBOutlet NSWindow *window; What does this mean? And the compiler can't even compile it. Thanks in advance! It indicates that this property is a strong relationship—an ownership. It's ARC 's version of the retain keyword in the same context. And the compiler can't even compile it. It's valid ARC code, so if your tools support ARC, they certainly should be able to compile it. Make sure that you're using Xcode 4.2 or later, and that you

I'm using the ARCified version of KeychainItemWrapper available at github , and I can't get it to store both email and password. KeychainItemWrapper *keychainItem = [[KeychainItemWrapper alloc] initWithIdentifier:@"myApp" accessGroup:@"MY_APP.com.yourcompany.GenericKeychainSuite"]; [keychainItem setObject:[self.email dataUsingEncoding:NSUTF8StringEncoding] forKey:(__bridge id)kSecAttrAccount]; [keychainItem setObject:self.password forKey:(__bridge id)kSecValueData]; I works perfectly as long as I store an email... that don't have an at sign (@) it. Otherwise, I get the error *** Assertion

When I do something simialr to the following I get an error saying for (UIView* att in bottomAttachments) { if (i <= [cells count]) { att = [[UIView alloc] extraStuff] } } Fast Enumeration variables cannot be modified in ARC: declare __strong What does __strong do and why must I add it? If a variable is declared in the condition of an Objective-C fast enumeration loop, and the variable has no explicit ownership qualifier, then it is qualified with const __strong and objects encountered during the enumeration are not actually retained. Rationale This is an optimization made possible because