automatic-ref-counting | 易学教程

iOS 7.0 and ARC: UITableView never deallocated after rows animation

阅读更多关于 iOS 7.0 and ARC: UITableView never deallocated after rows animation

问题 I have a very simple test app with ARC. One of the view controllers contains UITableView. After making row animations ( insertRowsAtIndexPaths or deleteRowsAtIndexPaths ) UITableView (and all cells) never deallocated. If I use reloadData , it works fine. No problems on iOS 6, only iOS 7.0. Any ideas how to fix this memory leak? -(void)expand { expanded = !expanded; NSArray* paths = [NSArray arrayWithObjects:[NSIndexPath indexPathForRow:0 inSection:0], [NSIndexPath indexPathForRow:1 inSection

Automatic Reference Counting Issue: Passing address of non-local object to __autoreleasing parameter for write-back

阅读更多关于 Automatic Reference Counting Issue: Passing address of non-local object to __autoreleasing parameter for write-back

问题 I'm trying to pass pointer to pointer to a method, but apparently ARC has some issues with how I'm doing it. Here the two methods: + (NSString *)personPropertyNameForIndex:(kSHLPersonDetailsTableRowIndex)index { static NSArray *propertyNames = nil; (nil == propertyNames) ? [self SHL_initPersonPropertyNamesWithArray:&propertyNames] : NULL; } + (void)SHL_initPersonPropertyNamesWithArray:(NSArray **)theArray { *theArray = [[NSArray alloc] initWithObjects:@"name", @"email", @"birthdate", @"phone"

Under ARC, are Blocks automatically copied when assigned to an ivar directly?

阅读更多关于 Under ARC, are Blocks automatically copied when assigned to an ivar directly?

问题 Assume the following code under ARC, typedef void (^MyResponseHandler) (NSError *error); @interface MyClass : NSObject { MyResponseHandler _ivarResponseHandler; } - (void)myMethod:(MyResponseHandler)responseHandler { _ivarResponseHandler = responseHandler; ... } Question: Is the block automatically copied to the heap when assigned to the ivar? My previous question implied that it is copied when assigned through a @property . But, today I used the above code and received an EXC_BAD_ACCESS that

Objective C - Custom setter with ARC?

阅读更多关于 Objective C - Custom setter with ARC?

问题 Here is how I used to write a custom retained setter before: - (void)setMyObject:(MyObject *)anObject { [_myObject release], _myObject = nil; _myObject = [anObject retain]; // Other stuff } How can I achieve this with ARC when the property is set to strong. How can I make sure that the variable has strong pointer? 回答1: The strong takes care of itself on the ivar level, so you can merely do - (void)setMyObject:(MyObject *)anObject { _myObject = anObject; // other stuff } and that's it. Note:

How to disable ARC for a single file in Xcode 5?

阅读更多关于 How to disable ARC for a single file in Xcode 5?

问题 I recently downloaded Xcode 5, and it's now my primary IDE. However, I now need to disable Automatic Reference Counting for a single file in my project. In Xcode 4, I went to the Build Phases tab under my target, and I could double click the on the right side of a row in the Compile Sources section, add -fno-objc-arc to the list of compiler flags, and be off. In 5, however, the column seems to be unclickable: So, how do I do this? 回答1: Well, I just tried and found that you must had dragged

Link Errors with Parse.framework iOS

阅读更多关于 Link Errors with Parse.framework iOS

问题 I tried importing the parse framework in my project. I made sure it is liked with my project and I couldn't find anything about whether it is 'arc sensitive' or not. My project is arc based. This is the error I'm getting: Undefined symbols for architecture i386: "_SCNetworkReachabilityCreateWithName", referenced from: -[PFCommandCache init] in Parse(PFCommandCache.o) +[PFInternalUtils(Reachability) isParseReachable] in Parse(PFInternalUtils.o) "_SCNetworkReachabilityGetFlags", referenced from

Retain Cycle in ARC

阅读更多关于 Retain Cycle in ARC

I have never worked on non ARC based project. I just came across a zombie on my ARC based project. I found it was because of retain cycle.I am just wondering what is a retain cycle.Can Could you give me an example for retain cycle? A retain cycle is a situation when object A retains object B , and object B retains object A at the same time * . Here is an example: @class Child; @interface Parent : NSObject { Child *child; // Instance variables are implicitly __strong } @end @interface Child : NSObject { Parent *parent; } @end You can fix a retain cycle in ARC by using __weak variables or weak

Is it possible to debug “Terminated due to memory error”?

阅读更多关于 Is it possible to debug “Terminated due to memory error”?

In a certain (consistent) point when my app is running, I consistently get the xcode error message Terminated due to memory error. I cannot find the code causing the error, but I can tell what code is near the error (using breakpoints). The error is caused directly after returning a certain cell in my implemenation of the - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath UITableViewDataSource delegate method. I can confirm that it is returning a valid UITableViewCell , but I think that explaining and posting that entire method would be a

Set delegates to nil under ARC?

阅读更多关于 Set delegates to nil under ARC?

问题 I'm writing iOS apps using ARC and targeting iOS 5+. Suppose I write a custom view object that has a delegate property. In declaring the delegate property, I make it a weak reference to avoid a retain cycle, so that when the actual delegate object (the controller) is destroyed, my custom view will also be destroyed, as follows: @interface MyCustomView : UIView @property (nonatomic, weak) id<MyCustomViewDelegate> delegate; @end All is good. Ok, so now I'm writing the controller object, and it

Should I still copy/Block_copy the blocks under ARC?

阅读更多关于 Should I still copy/Block_copy the blocks under ARC?

问题 I've just stumbled over the following SO topic: Why should we copy blocks rather than retain? which has the following sentence: However, as of iOS 6 they are treated as regular objects so you don't need to worry. I was really confused by this assertion that is why I am asking: does this assertion really imply that Objective-C developers do not need to @property (copy) blockProperties or [^(...){...) {} copy] to copy blocks and their contents from stack to heap anymore? I hope the description