objective-c - 不兼容的Objective-C类型警告

我有一个通过iPhone应用程序使用的用户类，这是我的用户类（NSobject的子类）中的init和initWithUser函数，当我使用initWithUser函数时，收到代码后描述的警告。请指教。

// serialize.h
#import <Foundation/Foundation.h>

@protocol Serialize

// serialize the object to an xml string
-(NSString*)ToXML;

@end


// user.h
#import <Foundation/Foundation.h>
#import "Serialize.h"
#import "Contact.h"


@interface User : NSObject <Serialize> {

NSString *email;
NSString *firstName;
NSString *lastName;
NSString *userId;
NSString *userName;
NSString *password;

NSMutableArray *contactList;

}

@property (nonatomic,copy) NSString *email;
@property (nonatomic,copy) NSString *firstName;
@property (nonatomic,copy) NSString *lastName;
@property (nonatomic,copy) NSString *userId;
@property (nonatomic,copy) NSString *userName;
@property (nonatomic,copy) NSString *password;
@property (nonatomic, retain) NSMutableArray *contactList;

//-(id)init;
-(id)initWithUser:(User *)copyUser;

@end



// user.m
#import "user.h"


@implementation User

@synthesize email;
@synthesize firstName;
@synthesize lastName;
@synthesize userId;
@synthesize userName;
@synthesize password;
@synthesize contactList;

-(id)init
{
    // call init in parent and assign to self
    if( (self = [super init]) )
    {
        // do something specific
        contactList = [[NSMutableArray alloc] init];

    }
    return self;
}

-(id)initWithUser:(User *)copyUser
{
    if( (self = [self init]) ) {

        email               = copyUser.email;
        firstName           = copyUser.firstName;
        lastName            = copyUser.lastName;
        userId              = copyUser.userId;
        userName            = copyUser.userName;
        password            = copyUser.password;

        // release contactList initialized in the init
        [contactList release];
        contactList         = [copyUser.contactList mutableCopy];
    }

    return self;
}

- (void)dealloc
{
    // TODO:
    [contactList removeAllObjects];
    [contactList release];
    [super dealloc];
}

// implementation of serialize protocol
-(NSString*)ToXML
{
    return @"";
}

我这样在主控制器上使用它

- (void) registerNewUser {

    RegistrationViewController *regController = [[RegistrationViewController alloc] init] ;

    regController.newUser = [[User alloc] initWithUser:self.user];

    [self.navigationController pushViewController:regController animated:YES];
    [regController release];

}

线

regController.newUser = [[User alloc] initWithUser:self.user];

给我以下错误，并且让我发疯了几天。


不兼容的Objective-c类型'struct User *'，当传递来自不同Objective-c类型的'initWithUser：'参数1时，预期为'struct NSString *'


任何帮助和指导表示赞赏

最佳答案

问题是您的选择器不明确。因为alloc返回id，所以对initWithUser:的调用变得模棱两可。 NSUserDefaults还有一个initWithUser:函数，该函数采用字符串。编译器认为您正在尝试使用该代码。将行更改为

regController.newUser = [(User*)[User alloc] initWithUser:self.user];

一切都会按预期进行。