//TextValidator.h
#import <Foundation/Foundation.h>
 
@interface TextValidator : NSObject
- (BOOL) isValidPassword:(NSString *)checkPassword;
- (BOOL) isValidEmail:(NSString *)checkString;
- (BOOL) isEmpty:(NSString *)checkString;
@end 
 
 
//  TextValidator.m
#import "TextValidator.h"
 
@implementation TextValidator
 
- (BOOL) isEmpty:(NSString *)checkString
{
    return YES;
}
 
- (BOOL) isValidPassword:(NSString *)checkPassword
{
return YES;
}
 
- (BOOL) isValidEmail:(NSString *)checkString
{
return YES;
}
 
@end

这是我尝试在ViewController.m中初始化TextValidator类的方法：

//ViewController.h
#import <Foundation/Foundation.h>
 
@interface SignUpViewController : UIViewController <UITextFieldDelegate>
@end
 
//ViewController.m
#import "SignUpViewController.h"
#import "TextValidator.h"
 
@interface SignUpViewController ()
 
@property TextValidator *myValidator;
 
@end
 
@implementation SignUpViewController
 
- (void)viewDidLoad
{
    [[self.myValidator alloc] init]; //iOS error: No visible @interface for 'TextValidator' declares the selector 'alloc'*
    [super viewDidLoad];
}
@end

当我尝试编译代码时,我收到以下错误：

No visible @interface for 'TextValidator' declares the selector 'alloc'.

TextValidator类继承自NSObject,据我所知,init和alloc函数已在基类中定义.那么为什么程序会出现这样的错误呢？

请注意,我已经检查了this主题,但它对我不起作用.