Objective-C Index Array

Question

I'm building a (joke) app based on tinder's card swiping that enables me to keep score of a Magic the Gathering Game.

In the past, I've simply done this by incrementing and decrementing numbers as strings through. This worked fine.

Now I'm using Richard Kim's TinderSimpleSwipeCards , which loads cards from an array with integers. There is a method called to load the next number in the array when the card is swiped. Being new to Objective-C, I've spent an hour trying to repurpose the array to my needs. But I'm stuck.

Since players can gain and lose life in Magic The Gathering, my goal is to be able to first load 20, then swipe right to increase the number, and swipe left in decrease the number (down to 0).

My first idea was to create an array with 40 numbers, then have the method start at index of 20, which would load the card with the integer 20. Then, by calling the method in either direction, I could load cards in the positive or negative direction.

But that didn't work.

Here is Richard's DraggableViewBackground.m file. He calls the method in -(void)loadCards, which is where I've been attempting to manipulate the index number.

I'm fairly certain this can't be done using an array by simply starting at an index in the middle then running a For Loop in either direction (i-1) or (i+1). When I do call the object at a specific index number, the method will just continue to create cards at that index (for example, if I createDraggableViewWithDataAtIndex:4, a new card of 16 - the 5th item in the array will just continue to load the card with 16).

Can someone please confirm this can or cannot be done with a single array? If it can, could someone please lead me in the direction of how to load a card from the correct index?

 //
//  DraggableViewBackground.m
//  testing swiping
//
//  Created by Richard Kim on 8/23/14.
//  Copyright (c) 2014 Richard Kim. All rights reserved.
//

#import "DraggableViewBackground.h"

@implementation DraggableViewBackground{
    NSInteger cardsLoadedIndex; //%%% the index of the card you have loaded into the loadedCards array last
    NSMutableArray *loadedCards; //%%% the array of card loaded (change max_buffer_size to increase or decrease the number of cards this holds)

    UIButton* menuButton;
    UIButton* messageButton;
    UIButton* checkButton;
    UIButton* xButton;
}
//this makes it so only two cards are loaded at a time to
//avoid performance and memory costs
static const int MAX_BUFFER_SIZE = 2; //%%% max number of cards loaded at any given time, must be greater than 1
static const float CARD_HEIGHT = 200; //%%% height of the draggable card
static const float CARD_WIDTH = 290; //%%% width of the draggable card

@synthesize exampleCardLabels; //%%% all the labels I'm using as example data at the moment
@synthesize allCards;//%%% all the cards

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [super layoutSubviews];
        [self setupView];
        exampleCardLabels = [[NSArray alloc]initWithObjects:@"20",@"19",@"18",@"17",@"16",@"15",@"14",@"13",@"12",@"11",@"10",@"9",@"8",@"7",@"6",@"5",@"4",@"3",@"2",@"1",@"DEATH", nil]; //%%% placeholder for card-specific information
        loadedCards = [[NSMutableArray alloc] init];
        allCards = [[NSMutableArray alloc] init];
        cardsLoadedIndex = 0;

        [self loadCards];
    }
    return self;
}

//%%% sets up the extra buttons on the screen
-(void)setupView
{
#warning customize all of this.  These are just place holders to make it look pretty
    self.backgroundColor = [UIColor colorWithRed:.92 green:.93 blue:.95 alpha:1]; //the gray background colors
    menuButton = [[UIButton alloc]initWithFrame:CGRectMake(17, 34, 22, 15)];
    [menuButton setImage:[UIImage imageNamed:@"menuButton"] forState:UIControlStateNormal];
    messageButton = [[UIButton alloc]initWithFrame:CGRectMake(284, 34, 18, 18)];
    [messageButton setImage:[UIImage imageNamed:@"messageButton"] forState:UIControlStateNormal];
    xButton = [[UIButton alloc]initWithFrame:CGRectMake(60, 485, 59, 59)];
    [xButton setImage:[UIImage imageNamed:@"xButton"] forState:UIControlStateNormal];
    [xButton addTarget:self action:@selector(swipeLeft) forControlEvents:UIControlEventTouchUpInside];
    checkButton = [[UIButton alloc]initWithFrame:CGRectMake(200, 485, 59, 59)];
    [checkButton setImage:[UIImage imageNamed:@"checkButton"] forState:UIControlStateNormal];
    [checkButton addTarget:self action:@selector(swipeRight) forControlEvents:UIControlEventTouchUpInside];
    [self addSubview:menuButton];
    [self addSubview:messageButton];
    [self addSubview:xButton];
    [self addSubview:checkButton];
}

#warning include own card customization here!
//%%% creates a card and returns it.  This should be customized to fit your needs.
// use "index" to indicate where the information should be pulled.  If this doesn't apply to you, feel free
// to get rid of it (eg: if you are building cards from data from the internet)
-(DraggableView *)createDraggableViewWithDataAtIndex:(NSInteger)index
{
    DraggableView *draggableView = [[DraggableView alloc]initWithFrame:CGRectMake((self.frame.size.width - CARD_WIDTH)/2, (self.frame.size.height - CARD_HEIGHT)/2, CARD_WIDTH, CARD_HEIGHT)];
    draggableView.information.text = [exampleCardLabels objectAtIndex:index]; //%%% placeholder for card-specific information
    draggableView.delegate = self;
    return draggableView;
}

//%%% loads all the cards and puts the first x in the "loaded cards" array
-(void)loadCards
{
    if([exampleCardLabels count] > 0) {
        NSInteger numLoadedCardsCap =(([exampleCardLabels count] > MAX_BUFFER_SIZE)?MAX_BUFFER_SIZE:[exampleCardLabels count]);
        //%%% if the buffer size is greater than the data size, there will be an array error, so this makes sure that doesn't happen

        //%%% loops through the exampleCardsLabels array to create a card for each label.  This should be customized by removing "exampleCardLabels" with your own array of data
        for (int i = 0; i<[exampleCardLabels count]; i++) {


            DraggableView* newCard = [self createDraggableViewWithDataAtIndex:i];
            [allCards addObject:newCard];

            if (i<numLoadedCardsCap) {
                //%%% adds a small number of cards to be loaded
                [loadedCards addObject:newCard];
            }
        }

        //%%% displays the small number of loaded cards dictated by MAX_BUFFER_SIZE so that not all the cards
        // are showing at once and clogging a ton of data
        for (int i = 0; i<[loadedCards count]; i++) {
            if (i>0) {
                [self insertSubview:[loadedCards objectAtIndex:i] belowSubview:[loadedCards objectAtIndex:i-1]];
            } else {
                [self addSubview:[loadedCards objectAtIndex:i]];
            }
            cardsLoadedIndex++; //%%% we loaded a card into loaded cards, so we have to increment
        }
    }
}

#warning include own action here!
//%%% action called when the card goes to the left.
// This should be customized with your own action
-(void)cardSwipedLeft:(UIView *)card;
{
    //do whatever you want with the card that was swiped
    //    DraggableView *c = (DraggableView *)card;

    [loadedCards removeObjectAtIndex:0]; //%%% card was swiped, so it's no longer a "loaded card"

    if (cardsLoadedIndex < [allCards count]) { //%%% if we haven't reached the end of all cards, put another into the loaded cards
        [loadedCards addObject:[allCards objectAtIndex:cardsLoadedIndex]];
        cardsLoadedIndex++;//%%% loaded a card, so have to increment count
        [self insertSubview:[loadedCards objectAtIndex:(MAX_BUFFER_SIZE-1)] belowSubview:[loadedCards objectAtIndex:(MAX_BUFFER_SIZE-2)]];
    }
}

#warning include own action here!
//%%% action called when the card goes to the right.
// This should be customized with your own action
-(void)cardSwipedRight:(UIView *)card
{
    //do whatever you want with the card that was swiped
    //    DraggableView *c = (DraggableView *)card;

    [loadedCards removeObjectAtIndex:0]; //%%% card was swiped, so it's no longer a "loaded card"

    if (cardsLoadedIndex < [allCards count]) { //%%% if we haven't reached the end of all cards, put another into the loaded cards
        [loadedCards addObject:[allCards objectAtIndex:cardsLoadedIndex]];
        cardsLoadedIndex++;//%%% loaded a card, so have to increment count
        [self insertSubview:[loadedCards objectAtIndex:(MAX_BUFFER_SIZE-1)] belowSubview:[loadedCards objectAtIndex:(MAX_BUFFER_SIZE-2)]];
    }

}

//%%% when you hit the right button, this is called and substitutes the swipe
-(void)swipeRight
{
    DraggableView *dragView = [loadedCards firstObject];
    dragView.overlayView.mode = GGOverlayViewModeRight;
    [UIView animateWithDuration:0.2 animations:^{
        dragView.overlayView.alpha = 1;
    }];
    [dragView rightClickAction];
}

//%%% when you hit the left button, this is called and substitutes the swipe
-(void)swipeLeft
{
    DraggableView *dragView = [loadedCards firstObject];
    dragView.overlayView.mode = GGOverlayViewModeLeft;
    [UIView animateWithDuration:0.2 animations:^{
        dragView.overlayView.alpha = 1;
    }];
    [dragView leftClickAction];
}

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
    // Drawing code
}
*/

@end

Answer 1

If I understood you correctly, an array is not necessary. I would save the current index of the cards in an integer value and a method to increase and decrease it by checking bounds. There is already an ivar NSInteger cardsLoadedIndex;

In my opionion a method like this would work:

- (NSUInteger) getIndexDirectionRight:(BOOL)direction{
    if (direction){
        return (cardsLoadedIndex < MAX_VALUE) ? cardsLoadedIndex + 1 : 0;
    }else{
        return (cardsLoadedIndex > 0) ? cardsLoadedIndex - 1 : MAX_VALUE;
    }
}

And you can call the method in swipeRight or swipeLeft and you initialize the cardsLoadedIndex to 20 in the initWithFrame method (as it is already set to 0).