Calling a method from a different view controller - ios

Question

I've been exploring virtual card deck randomisation and drawing of cards as a little side hobby recently, and have been focussing on a great tutorial found at Ontswedder. However, I've run into a minor issue which I'm hoping you can help me with!
Below, I've included some key aspects of the code for your viewing.
In my viewController, I'm wanting to call both the shuffle and draw methods, found in Deck.m. This is possible if I do the following:
Deck *d = [[Deck alloc] init];
[d shuffle];
[d deal];
However, I need to be able to split these. For example, clicking one button initialises the deck, and shuffles it, whilst another new button draws a new card (until the deck is empty).
I am having issues with this, and I could do the following:
Deck *d = [[Deck alloc] init];
[d shuffle];
Deck *d = [[Deck alloc] init];
[d deal];
But this is useless to me, as if I call the init then a NEW, UNSHUFFLED deck is created and the card is dealt from this new deck.
I've tried declaring Deck *DeckObject in viewController.h, then simply calling [DeckObject draw];, however this provides a null value.
Ultimately, I would like to call these two methods separately. Without needing to init a new deck every time if possible!! :-)
I greatly appreciate both everyone's help on this post but also site-wide!
I hope this makes sense, too. Please let me know if you would like more information.
Also, I apologise if any of my terminology is incorrect - still a bit of a newbie!
Included code for context:
Card.h
typedef enum {
Hearts,
Diamonds,
Spades,
Clubs
} Suit;
#define Ace 1
#define Jack 11
#define Queen 12
#define King 13
#interface Card : NSObject {
NSInteger value;
Suit suit;
}
#property (nonatomic) NSInteger value;
#property (nonatomic) Suit suit;
- (id) initWithValue:(NSInteger) aValue suit:(Suit) aSuit;
#end
Card.m
#interface Card(Private)
- (NSString *) valueAsString;
- (NSString *) suitAsString;
#end
#implementation Card
#synthesize value,suit;
- (id) initWithValue:(NSInteger) aValue suit:(Suit) aSuit {
if(self = [super init]) {
self.value = aValue;
self.suit = aSuit;
}
return self;
}
- (NSString *) valueAsString {
switch (self.value) {
case Ace:
return #"Ace";
break;
case Jack:
return #"Jack";
break;
case Queen:
return #"Queen";
break;
case King:
return #"King";
break;
default:
return [NSString stringWithFormat:#"%d",self.value];
break;
}
}
- (NSString *) suitAsString {
switch (self.suit) {
case Hearts:
return #"Hearts";
break;
case Diamonds:
return #"Diamonds";
break;
case Spades:
return #"Spades";
break;
case Clubs:
return #"Clubs";
break;
default:
return nil;
break;
}
}
- (NSString *) description {
return [NSString stringWithFormat:#"%# %#",
[self valueAsString],
[self suitAsString]];
}
#end
Deck.h
#interface Deck : NSObject {
#private
NSMutableArray *cards;
}
- (void) shuffle;
- (Card *) draw;
- (NSInteger) cardsRemaining;
#end
Deck.m
#implementation Deck
- (id) init {
if(self = [super init]) {
cards = [[NSMutableArray alloc] init];
for(int suit = 0; suit <= 3; suit++) {
for(int value = 1; value <= 13; value++) {
Card *card = [[Card alloc] initWithValue:value suit:suit];
[cards addObject:card];
[card release];
}
}
}
return self;
}
int randomSort(id obj1, id obj2, void *context ) {
// returns random number -1 0 1
return (arc4random()%3 - 1);
}
- (void) shuffle {
for(int x = 0; x < 500; x++) {
[cards sortUsingFunction:randomSort context:nil];
}
}
- (Card *) draw {
if([self cardsRemaining] > 0) {
Card *card = [[cards lastObject] retain];
[cards removeLastObject];
return [card autorelease];
}
NSException* myException = [NSException
exceptionWithName:#"OutOfCardsException"
reason:#"Tried to draw a card from a deck with 0 cards." userInfo:nil]; #throw
myException;
}
- (NSInteger) cardsRemaining {
return [cards count];
}
- (NSString *) description {
NSString *desc = [NSString stringWithFormat:#"Deck with %d cards\n",[self
cardsRemaining]];
for(int x = 0; x < [self cardsRemaining]; x++) {
desc = [desc stringByAppendingFormat:#"%#\n",[[cards objectAtIndex:x] description]];
}
return desc;
}
- (void) dealloc {
[cards release];
[super dealloc];
}
#end

Answer 1

When you declare the property deckObject, that just creates the pointer, you still have to alloc init a Deck object to create an instance.
self.deckObject = [[Deck alloc] init];
Then, you can use [self.deckObject shuffle] and [self.deckObject deal]in different button methods.

Answer 2

you have to declaring Deck *DeckObject in viewController.h as below
#interface firstViewController : UIViewController {
Deck *DeckObject;
}
Now in viewController.m file's viewDidLoad method initialize it like below
Deck *DeckObject = [[Deck alloc] init];
after that you can call methods in uibutton's action method
- (IBAction)BtnShuffle:(id)sender
{
if (DeckObject) {
[DeckObject shuffle];
}
}
and
- (IBAction)BtnDraw:(id)sender
{
if (DeckObject) {
[DeckObject draw];
}
}