no declaration of property 'newGameButton' found in the interface

I tried to find an answer on the internet (this site too), but i cant find the correct answer.

Im trying to give a button an animation, so I used the QuartzCore Framework. But every time I want to play-test it, it gives me this annoying massage: no declaration of property 'newGameButton' found in the interface. I dont know what I did wrong or what I have to do now.

Here is my .h and .m file:

.h file:

#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>

@interface MainMenuViewController : UIViewController {

    IBOutlet UIButton* newGameButton;
   开发者_开发技巧 IBOutlet UIButton* statsButton;
    IBOutlet UIButton* settingsButton;

    CAKeyframeAnimation* popAnimation;

}
-(IBAction) newGame:(id)sender;
-(IBAction) showStats:(id)sender;
-(IBAction) showSettings:(id)sender;
@end

.m file:

#import "MainMenuViewController.h"
#import "TrafficAppDelegate.h"
#import "TrafficViewController.h"

@implementation MainMenuViewController


-(IBAction) newGame:(id)sender{
    TrafficViewController* traffic = [[TrafficViewController alloc] initWithNibName:@"TrafficViewController" bundle:nil];
    [self.navigationController pushViewController:traffic animated:NO];
}

-(IBAction) showStats:(id)sender{
}
-(IBAction) showSettings:(id)sender{
}

@synthesize newGameButton, statsButton, settingsButton; (This is the error causer!)

-(void)viewDidLoad{

    [super viewDidLoad];

    popAnimation = [CAKeyframeAnimation animationWithKeyPath:@"transform.scale"];

    popAnimation.keyTimes = [NSArray arrayWithObjects:[NSNumber numberWithFloat:0.0], [NSNumber numberWithFloat:0.7], [NSNumber numberWithFloat:1.0], nil];
    popAnimation.values = [NSArray arrayWithObjects: [NSNumber numberWithFloat:0.01], [NSNumber numberWithFloat:1.1], [NSNumber numberWithFloat:1.0], nil];


    [popAnimation retain];

}

-(void)popView:(UIView*)view{
    [view setHidden:NO];
    [[view layer] addAnimation:popAnimation forKey:@"transform.scale"];
}

-(void)viewWillAppear:(BOOL)animated{
    [popAnimation setDuration:0.3];
    [newGameButton setHidden:YES];
    [statsButton setHidden:YES];
    [settingsButton setHidden:YES];
    [self performSelector:@selector(popView:) withObject:newGameButton afterDelay:0.25];
    [self performSelector:@selector(popView:) withObject:statsButton afterDelay:0.3];
    [self performSelector:@selector(popView:) withObject:settingsButton afterDelay:0.35];
}

@end

I am totally clueless, so please help!

The error is self-descriptive - you need to declare properties you synthesize in class interface, e.g.:

@interface MainMenuViewController : UIViewController {
   ...
}
...
@property (nonatomic, retain) IBOutlet UIButton* settingsButton;

@end

I'd suggest (Re-)reading about properties in Objective-c reference docs

You're trying to access a property that simply does not exist.

Look at your @interface, do you see any @property declarations?

This will work:

@interface MainMenuViewController : UIViewController {

    IBOutlet UIButton* newGameButton;
    IBOutlet UIButton* statsButton;
    IBOutlet UIButton* settingsButton;

    CAKeyframeAnimation* popAnimation;

}

@property (nonatomic, retain) IBOutlet UIButton *newGameButton, *statsButton, *settingsButton;