问题描述

在两个viewcontroller之间的delegation有问题

第一个viewcontroller是排行榜菜单，里面有一个按钮指示到第二个viewcontroller中第二个是小游戏，如果玩家输了，最高分变动，就更新排行榜。在玩家完成游戏时建了带两个按钮的UIAlertView，一个是主菜单，另一个是重新开始，我的代码如下：我想通过delegation更新排行榜

  @protocol highScoreProtocol <NSObject>        -(void)updateHighScore:(int) score;        @end        @interface ViewController : UIViewController <UIAlertViewDelegate>         @property (nonatomic) int score;        @property (nonatomic weak) id <highScoreProtocol> delegateHighScore;        @implementation ViewController        @synthesize score=_score;        @synthesize delegateHighScore=_delegateHighScore;            -(void)lostGame{            [self.delegateHighScore updateHighScore:self.score];         UIAlertView *losingScreen=[[UIAlertView alloc]initWithTitle:@""Game Over"" message:[NSString stringWithFormat:@""Your Score Is %d"" self.score] delegate:self cancelButtonTitle:@""Main Menu"" otherButtonTitles:@""Restart"" nil];             }        -(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{              if (buttonIndex==0) {            } else if (buttonIndex==1){            }        }    @end            @interface MenuVC : UIViewController <highScoreProtocol>            @property (weak nonatomic) IBOutlet UILabel *labelHighScore;    @end@implementation MenuVC- (void)viewDidLoad{    [super viewDidLoad];    ViewController *vc=[[ViewController alloc]init];    vc.delegateHighScore=self;}-(void)updateHighScore:(int)score{    if (score>[self.labelHighScore.text integerValue]) {         self.labelHighScore.text=[NSString stringWithFormat:@""%d"" score];    }    NSLog(@""does this method even run"");}

不知道哪出错了，希望大家帮忙。

解决方案

这行代码不对

ViewController *vc=[[ViewController alloc]init];vc.delegateHighScore=self;

定义了一个新的不相干的viewcontroller。

如果你的情况是这样：定义一个viewcontroller的identifier，选择viewcontroller，……

然后用这行代码：

ViewController *vc = [self.storyboard instantiateViewControllerWithIdentifier:@""yourIdentifier""];vc.delegateHighScore = self;