以“new”开头的属性名称在iOS中导致BAD_ACCESS错误 [英] Property name starting with 'new' prefix leads to BAD_ACCESS error in iOS

问题描述

我的属性被声明在我的NSManagedObject类名称为newPrice，它导致僵尸对象。经过几个小时的调试，我发现有一个问题，方法是释放这个对象，但不保留它。将此属性重命名为priceNew后，一切都很顺利。我不明白为什么会造成问题。

财产声明：

  @property（nonatomic，retain）NSNumber * newPrice; 
  

此调用导致问题：

  [self setPieceStateWithPrice：self.action.newPrice]; 
  

传递重命名的参数，如self.action.priceNew一切顺利...

$

在Objective-C命名约定中，方法的以 new 开头的名称将返回一个保留对象。使用ARC，该命名约定成为一个要求。这意味着一个正常的，ARC编译的方法不应该以 new 开头，因为编译器会假定它的保留计数为1.

引用文档：

您创建的任何对象

您使用名称以alloc开头的方法创建一个对象，
new，copy或mutableCopy（例如alloc，newObject或
mutableCopy）。

My property was declared in my NSManagedObject class with name "newPrice", which leads to "zombie object". After some hours of debugging I figured out that there is problem with method which is releasing this object but not retaining it. After renaming this property to "priceNew" everything goes well. I don't understand why this is causing problem.

Declaration of property:

@property (nonatomic, retain) NSNumber * newPrice;

This call causing problem:

[self setPieceStateWithPrice:self.action.newPrice];

After passing renamed argument like self.action.priceNew everything goes well...

解决方案

Don't do that.

In Objective-C naming conventions, methods whose names begin with new are expected to return a retained object. With ARC, that naming convention becomes a requirement. That means that a normal, ARC-compiled method should never start with the name new because the compiler will assume that it already has a retain count of 1.

To quote the docs:

You own any object you create

You create an object using a method whose name begins with "alloc", "new", "copy", or "mutableCopy" (for example, alloc, newObject, or mutableCopy).

这篇关于以“new”开头的属性名称在iOS中导致BAD_ACCESS错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！