傳入的場景在當前場景可以傳遞數據之前分配

Question

我想在兩個場景之間傳遞數據（分數）。但是，我的第二個場景是在第一個場景可以傳遞數據之前分配的。不知道爲什麼。我的代碼：

MainScreen.m

-(void)gameOver 
{ 

    self.view.scene.userData = [[NSMutableDictionary alloc]init]; 
    [self.view.scene.userData setObject:self.score forKey:@"score"]; 

    SVGGameOverScreen *gameOverScreen = [[SVGGameOverScreen alloc]initWithSize:self.size]; 
    gameOverScreen.view.scene.userData = [[NSMutableDictionary alloc]init]; 
    [gameOverScreen.userData setObject:[self.view.scene.userData objectForKey:@"score"] forKey:@"score"]; 

    NSLog(@"Value of score (FIRST SCREEN): %d", self.score.intValue); 
    NSLog(@"Value of object for score key (FIRST SCREEN) %@", [self.userData objectForKey:@"score"]); 

    [self.backgroundMusicPlayer stop]; 

    //Transition to new view 
    SKTransition *transition = [SKTransition pushWithDirection:SKTransitionDirectionUp duration:1.0]; 
    transition.pausesOutgoingScene = YES; 
    [self.view presentScene:gameOverScreen transition:transition]; 
} 

GameOverScreen.m

in init method 
... 
self.score = [[NSNumber alloc]init]; 
     self.score = [self.userData objectForKey:@"score"]; 
     NSLog(@"Value of object for score key (SECOND SCREEN) %@", [self.userData objectForKey:@"score"]); 

輸出如下GAMEOVER時被調用：

2013-12-18 15:47:48.646 [] Value of object for score key (SECOND SCREEN) (null) 
2013-12-18 15:47:48.700 [] Value of score (FIRST SCREEN): 26 
2013-12-18 15:47:48.700 [] Value of object for score key (FIRST SCREEN) 26 

Answer 1

如果你打電話

[SVGGameOverScreen alloc]initWithSize:self.size]; 

並且不要在其中設置userData，當然它不會被設置，直到方法返回。無論是寫抄錄你需要做的用戶數據被設置後，任何邏輯的新方法，它具有這樣的

initWithSize: (CGSize) size userData: (NSMutableDictionary*) userData 

的新方法傳遞到遊戲結束畫面，並將其設置裏面，或（可能更好）使自定義設置爲財產，並把邏輯在那裏。

順便說一句，爲什麼你創建一個NSNumber的分數只設置它等於值userData的「分數」鍵？