Properties 属性实现必须在接口错误中声明

属性实现必须在接口错误中声明

我有这个错误，我是新的xcode，所以我不知道该怎么做

我在一个类中有很多代码，然后我把它移到另一个类中，现在我有很多错误。这是没有道理的，因为一切看起来都应该如此

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController
@synthesize MenuScreenButton;
@synthesize HowToPlayButton;


- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


-(IBAction)HowToPlayButtonPressed:(id)sender

{
HowToPlayViewController *HowToPlayView=[[HowToPlayViewController alloc]initWithNibName:nil bundle:nil];
    HowToPlayView.modalTransitionStyle=UIModalTransitionStyleFlipHorizontal;
    [self presentViewController:HowToPlayView animated:YES completion:NULL];
}

-(IBAction)MenuScreenButtonPressed:(id)sender

{
    MenuScreen *MenuScreenView=[[MenuScreen alloc]initWithNibName:nil bundle:nil];
    MenuScreenView.modalTransitionStyle=UIModalTransitionStyleFlipHorizontal;
    [self presentViewController:MenuScreenView animated:YES completion:NULL];
}
@end

下面是.h文件：

#import <UIKit/UIKit.h>
#import "HowToPlayViewController.h"
#import "MenuScreen.h"

@interface ViewController : UIViewController
{
    IBOutlet UIButton *HowToPlayButton;
    IBOutlet UIButton *MenuScreenButton;

}



@property(retain,nonatomic) IBOutlet UIButton *MenuScreenButton;

@property(retain,nonatomic) IBOutlet UIButton *HowToPlayButton;

-(IBAction)HowToPlayButtonPressed:(id)sender;
-(IBAction)MenuScreenButtonPressed:(id)sender;
@end

---

您需要在@synthesis MenuScreenButton后面加一个分号，而不是逗号，还有ViewController中的内容。hI更正了逗号，但错误仍然显示为sadlyOk。首先，属性应该是小写的。其次，您使用的是最新版本的Xcode。其他错误是，对于以前在此类中但已移动的几个控制器，显示“使用未声明的标识符”？您可能缺少导入，或者如果不需要引用，则删除引用。顺便说一句，如果您使用的是最新版本的Xcode，那么您可以用更少的代码声明属性-您不需要@interface{}块中的UIButton声明，-只需要@property，也不需要@synthesis。您将属性声明为retain，因此我假设您没有使用ARC