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问题描述

我的应用程式因以下原因而崩溃:

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.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:

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 retain


My application crashed with the reason:

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.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:

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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08-14 12:40