iOS编译问题：Property's synthesized getter follows Cocoa naming convention for returning 'owned'

原文链接：http://www.tuicool.com/articles/UrUbY3J

该文章提供了角度比较全面的答案！！！

在项目中定义了以new开头的textField，结果报错：

先看我的源码：

#import <UIKit/UIKit.h>

@interface ResetPasswordViewController : UIViewController
@property (weak, nonatomic) IBOutlet UITextField *phoneTextField;
@property (weak, nonatomic) IBOutlet UITextField *oldPasswordTextField;
<span style="color:#FF0000;">@property (weak, nonatomic) IBOutlet UITextField *newPasswordTextField;</span>
@property (weak, nonatomic) IBOutlet UITextField *confirmPasswordTextField;
@property (weak, nonatomic) IBOutlet UINavigationItem *navigationItem;

@end

解决办法： 

最简单的方法是改我们定义属性的名字，不要以new、copy、alloc等关键词开头！！！

点击打开链接

y guess is that the compiler version you’re using follows the memory management rules for declared properties, too — more specifically, for declared properties’ accessors:

You take ownership of an object if you create it using a method whose name begins with “alloc”, “new”, “copy”, or “mutableCopy”.

A property named newTitle , when synthesised, yields a method called -newTitle , hence the warning/error. -newTitle is supposed to be a getter method for thenewTitle property, however naming conventions state that a method whose name begins with new returns an object that’s owned by the caller, which is not the case of getter methods.

You can solve this by:

1. Renaming that property:

   @property (strong, nonatomic) NSString *theNewTitle;

2. Keeping the property name and specifying a getter name that doesn’t begin with one of the special method name prefixes:

   @property (strong, nonatomic, getter=theNewTitle) NSString *newTitle;

3. Keeping both the property name and the getter name, and telling the compiler that, even though the getter name starts with new , it belongs to the none method family as opposed to the new method family:

   #ifndef __has_attribute
   #define __has_attribute(x) 0  // Compatibility with non-clang compilers
   #endif
   
   #if __has_attribute(objc_method_family)
   #define BV_OBJC_METHOD_FAMILY_NONE __attribute__((objc_method_family(none)))
   #else
   #define BV_OBJC_METHOD_FAMILY_NONE
   #endif
   
   @interface ViewController : UIViewController
   @property (strong, nonatomic) NSString *newTitle;
   - (NSString *)newTitle BV_OBJC_METHOD_FAMILY_NONE;
   @end

   Note that even though this solution allows you to keep newTitle as both the property name and the getter name, having a method called -newTitle that doesn’t return an object owned by the caller can be confusing for other people reading your code.

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For the record, Apple have published Transitioning to ARC Release Notes , in which they state:

You cannot give a property a name that begins with new or copy .

They’ve already been notified that their statement is not quite accurate: the culprit is the getter method name, not the property name.v