restart object in objective c - Matchismo Assignment 2 - Restart game - ios

Question

I was trying to solve assignment 2 from Stanford iOS7 development (Matchismo card game)
The game works fine. Now I have to add the Restart function. If the user press on the restart button, the game restarts (it deals new cards and it resets the score)
my game model is the #property (nonatomic, strong) CardMatchingGame *game;
this is the code for the CardMatchingGame.m:
#import "CardMatchingGame.h"
#import "PlayingCardDeck.h"
#interface CardMatchingGame()
#property (nonatomic, readwrite) NSInteger score;
#property (nonatomic, strong) NSMutableArray *cards;
#end
#implementation CardMatchingGame
static const int MATCH_BONUS = 4;
static const int MATCH_PENALTY = 2;
static const int COST_TO_CHOOSE = 1;
-(NSMutableArray *)cards{
if(!_cards) _cards = [[NSMutableArray alloc]init];
return _cards;
}
-(instancetype)initWithCardCount:(NSUInteger)count usingDeck:(Deck *)deck{
self = [super init];
if(self){
for(int i=0; i < count; i++){
Card *card = [deck drawRandomCard];
if(card){
[self.cards addObject:card];
} else{
self = nil;
break;
}
}
}
return self;
}
-(void)chooseCardAtIndex:(NSUInteger)index{
Card *card = [self cardAtIndex:index];
if(!card.isMatched){
if(card.isChosen){
card.chosen = NO;
} else{
for(Card *otherCard in self.cards){
if(otherCard.isChosen && !otherCard.isMatched){
int matchScore = [card match:#[otherCard]];
if(matchScore){
self.score += matchScore * MATCH_BONUS;
card.matched = YES;
otherCard.matched = YES;
} else{
self.score -= MATCH_PENALTY;
otherCard.chosen = NO;
}
break;
}
}
self.score -= COST_TO_CHOOSE;
card.chosen = YES;
}
}
}
-(Card *)cardAtIndex:(NSUInteger)index{
return (index < [self.cards count]) ? self.cards[index] : nil;
}
#end
here is my CardGameViewController.m:
#import "CardGameViewController.h"
#import "PlayingCardDeck.h"
#import "CardMatchingGame.h"
#interface CardGameViewController ()
#property (nonatomic, strong) Deck *deck;
#property (nonatomic, strong) CardMatchingGame *game;
#property (strong, nonatomic) IBOutletCollection(UIButton) NSArray *cardsCollection;
#property (weak, nonatomic) IBOutlet UILabel *scoreLabel;
#end
#implementation CardGameViewController
#synthesize game = _game;
-(CardMatchingGame *)game{
if(!_game) _game = [[CardMatchingGame alloc] initWithCardCount:[self.cardsCollection count]
usingDeck:self.deck];
return _game;
}
-(Deck *)deck{
if(!_deck) _deck = [[PlayingCardDeck alloc] init];
return _deck;
}
- (IBAction)touchRestartButton:(id)sender {
self.game = nil;
[self updateUI];
}
- (IBAction)touchCardButton:(UIButton *)sender {
int chosenButtonIndex = [self.cardsCollection indexOfObject:sender];
[self.game chooseCardAtIndex:chosenButtonIndex];
[self updateUI];
}
-(void)updateUI{
for(UIButton *cardButton in self.cardsCollection){
int buttonIndex = [self.cardsCollection indexOfObject:cardButton];
Card *card = [self.game cardAtIndex:buttonIndex];
[cardButton setTitle:[self titleForCard:card] forState:UIControlStateNormal];
[cardButton setBackgroundImage:[self backgroundImageForCard:card] forState:UIControlStateNormal];
cardButton.enabled = !card.isMatched;
}
self.scoreLabel.text = [NSString stringWithFormat:#"Score: %d", self.game.score];
}
-(NSString *)titleForCard:(Card *)card{
return card.isChosen ? card.contents : #"";
}
-(UIImage *)backgroundImageForCard:(Card *)card{
return [UIImage imageNamed: card.isChosen ? #"cardfront" : #"cardback"];
}
#end
In order to restart the game, I think I should simply re-initialize the property CardMatchingGame *game.
This is what I tried to do, by setting self.game = nil; Then it should automatically be re-initialized in the getter of game.
This is, indeed, the solution that I found on the internet. However, in my program it doesn't work. *game is set to nil and never restored, so the game ends when you click restart.
Could you please help me to figure out why self.game = nil doesn't work in my case?

Answer 1

- (IBAction)startover:(UIButton *)sender {
self.game= [[CardMatchingGame alloc] initWithCardCount:[self.cardButtons count] usingDeck:[self createDeck]];
[self updateUI];
}

Answer 2

If your program has the lazy init style recommended, there is no need for a new method such as start over. You are correct to set self.game to nil, now a call the the getter will start a new instance of the game. I did it by making a call to UIUpdate right after the self.game = nil. That has a call to the getter and lazily inits a new instance of the game.