- [MyClassName copyWithZone：]无法识别的选择器发送到实例 [英] -[MyClassName copyWithZone:] unrecognized selector sent to instance

问题描述

我的应用程式因以下原因而崩溃：

- [MyClassName copyWithZone：]无法识别的选择器发送到实例

我有两个类。让我们说Class1和Class2。

Class1看起来像：

Class1.h

  @interface Class1：NSObject {
 NSString * imagemd5CheckSum; 
 UIImage * image; 
 NSData * fileChunkData; 
} 
 
 @property（nonatomic，copy）NSString * imagemd5CheckSum; 
 @property（nonatomic，copy）UIImage * image; 
 @property（nonatomic，copy）NSData * fileChunkData; 
 
 @end 
  

Class1.m

  @implementation Class1 
 
 @synthesize image; 
 @synthesize fileChunkData; 
 @synthesize imagemd5CheckSum; 
 
  - （id）init {
 [self setImage：nil]; 
 [self setFileChunkData：nil]; 
 [self setImagemd5CheckSum：@]; 
 
 return self; 
} 
 
  - （void）dealloc {
 [imagemd5CheckSum release]; 
 [image release]; 
 [fileChunkData release]; 
 
 fileChunkData = nil; 
 imagemd5CheckSum = nil; 
 image = nil; 
 
 [super dealloc]; 
} 
 @end 
  

**

Class2看起来像

**

Class2.h

---

  #importClass2。 h
 @interface Class2：NSObject {
 Class1 * obj1; 
 Class1 * obj2; 
 Class1 * obj3; 
} 
 
 @property（nonatomic，copy）Class1 * obj1; 
 @property（nonatomic，copy）Class1 * obj2; 
 @property（nonatomic，copy）Class1 * obj3; 
 
 @end 
  

Class2.m

---

  @implementation Class2 
 
 @synthesize obj1，obj2，obj3; 
 
  - （id）init {
 [self setObj1：nil]; 
 [self setObj2：nil]; 
 [self setObj3：nil]; 
 
 return self; 
} 
 
  - （void）dealloc {
 [obj1 release]; 
 [obj2 release]; 
 [obj3 release]; 
 
 obj1 = nil; 
 obj2 = nil; 
 obj3 = nil 
 
 [super dealloc]; 
} 
 @end 
  

崩溃情况

  Class2 * class2 = [[Class2 alloc] init]; 
 
 Class1 * class1 = [[Class1 alloc] init]; 
 
 [class1 setImagemd5CheckSum：@this is md5]; 
 [class1 setImage：myimage]; 
 [class1 setFileChunkData：myData]; 
 
 [class2 setObj1：class1]; // this line is crashed .. 
  

...

当我调用 [class2 setObj1：class1]; 时，应用程序崩溃的原因：

- [Class1 copyWithZone：]发送到实例的无法识别的选择器

如何解决这个问题？ -setObj1：方法声明为

copy ，因此在 Class1 对象上调用 -copy -copy 只是调用 -copyWithZone：nil 。所以你需要实现 NSCopying 协议（这意味着实现 -copyWithZone：），或者更改你的属性从 copy 到 retain 。

My application crashed with the reason:

-[MyClassName copyWithZone:] unrecognized selector sent to instance

I have two classes. Let's say Class1 and Class2.

Class1 looks like:

Class1.h

@interface Class1 : NSObject {
    NSString *imagemd5CheckSum;
    UIImage *image;
    NSData *fileChunkData;
}

@property (nonatomic, copy)NSString *imagemd5CheckSum;
@property (nonatomic, copy)UIImage *image;
@property (nonatomic, copy)NSData *fileChunkData;

@end

Class1.m

@implementation Class1

@synthesize image;
@synthesize fileChunkData;
@synthesize imagemd5CheckSum;

-(id) init{
    [self setImage:nil];
    [self setFileChunkData:nil];
    [self setImagemd5CheckSum:@""];

    return self;
}

-(void)dealloc{
    [imagemd5CheckSum release];
    [image release];
    [fileChunkData release];

    fileChunkData = nil;
    imagemd5CheckSum = nil;
    image = nil;

    [super dealloc];
}
@end

**

Class2 looks like

**

Class2.h

---

#import "Class2.h"
@interface Class2 : NSObject {
    Class1 *obj1;
    Class1 *obj2;
    Class1 *obj3;
}

@property (nonatomic, copy)Class1 *obj1;
@property (nonatomic, copy)Class1 *obj2;
@property (nonatomic, copy)Class1 *obj3;

@end

Class2.m

---

@implementation Class2

@synthesize obj1,obj2,obj3;

-(id) init{
    [self setObj1:nil];
    [self setObj2:nil];
    [self setObj3:nil];

    return self;
}

-(void)dealloc{
    [obj1 release];
    [obj2 release];
    [obj3 release];

    obj1 = nil;
    obj2 = nil;
    obj3 = nil;

    [super dealloc];
}
@end

Crashed Situation

Class2 *class2 = [[Class2 alloc] init];

Class1 *class1 = [[Class1 alloc] init];

[class1 setImagemd5CheckSum:@"this is md5"];
[class1 setImage:myimage];
[class1 setFileChunkData:myData];

[class2 setObj1:class1]; // This line is crashed..

...

When I called [class2 setObj1:class1];, the application crashed with reason:

-[Class1 copyWithZone:] unrecognized selector sent to instance

How can I fix this problem?

解决方案

Your -setObj1: method is declared as copy, so it calls -copy on your Class1 object. -copy just calls -copyWithZone:nil. So you either need to implement the NSCopying protocol (which means implementing -copyWithZone:), or change your property from copy to retain.

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