Quickly Build an Input-Driven Game - Beginning iOS6 Games Development - page 81

@property (nonatomic, retain) NSMutableArray* coins;
@property (nonatomic) int remaingTurns;
@property (nonatomic) int score;
@property (nonatomic) int colCount;
@property (nonatomic) int rowCount;
-(id)initRandomWithRows:(int)rows Cols:(int)cols;
-(NSNumber*)coinForCoord:(Coord)coord;
-(int)indexForCoord:(Coord)coord;
-(void)swap:(Coord)coordA With:(Coord)coordB;
-(NSMutableArray*)findMatchingRows;
CoinsGame . At the very top of the class, we define
COIN_TRIANGLE , COIN_SQUARE , and COIN_CIRCLE . These values represent the three
Coord that is used to store a
Coord was used earlier in Listing 4-12 to identify a specific coin.
Coord . The first, called CoordMake , is used to create
Coord with the corresponding row and column values. The second, called CoordEqual , is used to
Coords are referring to the same coin.
The interface declaration for the class CoinsGame , shown in Listing 4-13, conforms to the protocol
NSCoding , so we know we can archive and unarchive instances of this class. We also see that an
NSMutableArray called coins is defined. The coins object is used to store the NSNumber values that
represent the coins at each coordinate. In addition, ints are used to keep track of the number of
remaining turns, the score, and the number of rows and columns used in this game.
There are various tasks defined for the class CoinsGame , and hopefully some of these make sense
already. We know we will need a way to swap two coins, so the use of the swap:With: task should
make sense. There are also two tasks, findMatchingRows and findMatchingCols , which are used
to determine whether any matches exist. The tasks randomizeRows and randomizeCols are used
to set new coin values after a match has been found. Notice that findMatchingRows returns an
NSMutableArray and that randomizeRows takes an NSMutableArray . The idea here is that after a match
is found and the animations are all done, we can use the same NSMutableArray that represented the
match to indicate which coins should be randomized.
Listing 4-13 also has two tasks that take a Coord as an argument. The first one, coinForCoord: ,
takes a Coord and returns NSNumber , indicating the coin type for that coordinate. The second task,
indexForCoord , is used to translate a Coord into int suitable as an index into an array. This task is
used to find the coin NSNumber in coinForCoord , and it is also used by CoinsController to find the
correct UIImageView for a coin.
Let's take a look at the implementation of some of the tasks, because they will be called by
CoinsController at different points. We'll start with initRandomWithRow:Col: , shown in Listing 4-14.