Scroll view project

viewcontroller.m

//
//  ViewController.m
//  ThreeScrollViewProject
//
//  Created by Echelon Creative on 8/25/16.
//  Copyright © 2016 Energy Echelon. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
{
    float screenWidth, scrollViewWidth, scrollViewHeight;
    float vertScrollViewOffset, horizScrollViewOffset;
    
    float topStart, topEnd, midStart, midEnd, botStart, botEnd;
    float imgWidth, imgHeight;
    
    int outfitCount;
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    imgWidth = 1131;
    imgHeight = 3244;
    
    topStart = 1;   // Really not needed and not used for the sake of simplicity.
    topEnd = 1838;
    midStart = 1320;
    midEnd = 2987;
    botStart = 2792;
    botEnd = imgHeight;
    
    screenWidth = self.view.bounds.size.width;
    scrollViewWidth = 3.0 * screenWidth / 5.0;
    scrollViewHeight = scrollViewWidth * imgHeight / imgWidth;
    
    vertScrollViewOffset = 20;  // Choose manually to shift the images away from status bar.
    horizScrollViewOffset = screenWidth / 5.0;
    
    outfitCount = 3;
    
    // Manual initialization of three scrollviews. The calculations are based on 33% additional view
    // provision on left and right of the main image. In other words, the page width is 3/5 of screenWidth
    
    /////////////// Naked view starts here.
    UIImageView *nakedImageView = [[UIImageView alloc] initWithFrame:CGRectMake(horizScrollViewOffset, vertScrollViewOffset, scrollViewWidth, scrollViewHeight)];
    nakedImageView.image = [UIImage imageNamed:@"naked.png"];
    [self.view addSubview:nakedImageView];
    
    
    /////////////// Bottom scrollview starts here ////////////////
    UIScrollView *botScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(horizScrollViewOffset, vertScrollViewOffset + scrollViewHeight * botStart / imgHeight, scrollViewWidth, scrollViewHeight * (imgHeight - botStart + 1) / imgHeight)];
    botScrollView.contentSize = CGSizeMake( (outfitCount + 2) * scrollViewWidth, botScrollView.frame.size.height);
    
    UIImageView *botImageView = [[UIImageView alloc] init];
    
    // Populate the first image
    botImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, scrollViewWidth,botScrollView.frame.size.height)];
    botImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"bot%d.png",outfitCount-1]];
    [botScrollView addSubview:botImageView];
    
    // Populate last image
    botImageView = [[UIImageView alloc] initWithFrame:CGRectMake( (outfitCount + 1) * scrollViewWidth, 0, scrollViewWidth,botScrollView.frame.size.height)];
    botImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"bot%d.png",0]];
    [botScrollView addSubview:botImageView];
    
    // Populate middle images
    for (int i = 0; i < outfitCount; i++) {
        botImageView = [[UIImageView alloc] initWithFrame:CGRectMake( (i + 1) * scrollViewWidth, 0, scrollViewWidth,botScrollView.frame.size.height)];
        botImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"bot%d.png",i]];
        [botScrollView addSubview:botImageView];
    }
    
    [botScrollView setBackgroundColor:[UIColor clearColor]];
    botScrollView.clipsToBounds = FALSE;
    botScrollView.delegate = self;
    [botScrollView setContentOffset:CGPointMake(scrollViewWidth,0)];
    botScrollView.pagingEnabled = TRUE;
    
    [self.view addSubview:botScrollView];
    
    
    /////////////// Middle scrollview starts here ////////////////
    UIScrollView *midScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(horizScrollViewOffset, vertScrollViewOffset + scrollViewHeight * midStart / imgHeight, scrollViewWidth, scrollViewHeight * (midEnd - midStart + 1) / imgHeight)];
    midScrollView.contentSize = CGSizeMake( (outfitCount + 2) * midScrollView.frame.size.width, midScrollView.frame.size.height);
    
    UIImageView *midImageView = [[UIImageView alloc] init];
    
    // Populate the first image
    midImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, scrollViewWidth,midScrollView.frame.size.height)];
    midImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"mid%d.png",outfitCount-1]];
    [midScrollView addSubview:midImageView];
    
    // Populate last image
    midImageView = [[UIImageView alloc] initWithFrame:CGRectMake( (outfitCount + 1) * scrollViewWidth, 0, scrollViewWidth,midScrollView.frame.size.height)];
    midImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"mid%d.png",0]];
    [midScrollView addSubview:midImageView];
    
    // Populate middle images
    for (int i = 0; i < outfitCount; i++) {
        midImageView = [[UIImageView alloc] initWithFrame:CGRectMake( (i + 1) * scrollViewWidth, 0, scrollViewWidth,midScrollView.frame.size.height)];
        midImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"mid%d.png",i]];
        [midScrollView addSubview:midImageView];
    }
    
    [midScrollView setBackgroundColor:[UIColor clearColor]];
    midScrollView.clipsToBounds = FALSE;
    midScrollView.delegate = self;
    [midScrollView setContentOffset:CGPointMake(scrollViewWidth,0)];
    midScrollView.pagingEnabled = TRUE;
    
    [self.view addSubview:midScrollView];
    
    
    /////////////// Top scrollview starts here ////////////////
    UIScrollView *topScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(horizScrollViewOffset, vertScrollViewOffset, scrollViewWidth, scrollViewHeight * topEnd / imgHeight)];
    topScrollView.contentSize = CGSizeMake( (outfitCount + 2) * topScrollView.frame.size.width, topScrollView.frame.size.height);
    
    UIImageView *topImageView = [[UIImageView alloc] init];
    
    // Populate the first image
    topImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, scrollViewWidth,topScrollView.frame.size.height)];
    topImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"top%d.png",outfitCount-1]];
    [topScrollView addSubview:topImageView];
    
    // Populate last image
    topImageView = [[UIImageView alloc] initWithFrame:CGRectMake( (outfitCount + 1) * scrollViewWidth, 0, scrollViewWidth,topScrollView.frame.size.height)];
    topImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"top%d.png",0]];
    [topScrollView addSubview:topImageView];
    
    // Populate middle images
    for (int i = 0; i < outfitCount; i++) {
        topImageView = [[UIImageView alloc] initWithFrame:CGRectMake( (i + 1) * scrollViewWidth, 0, scrollViewWidth,topScrollView.frame.size.height)];
        topImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"top%d.png",i]];
        [topScrollView addSubview:topImageView];
    }
    
    [topScrollView setBackgroundColor:[UIColor clearColor]];
    topScrollView.clipsToBounds = FALSE;
    topScrollView.delegate = self;
    [topScrollView setContentOffset:CGPointMake(scrollViewWidth,0)];
    topScrollView.pagingEnabled = TRUE;
    
    [self.view addSubview:topScrollView];
}

- (void)scrollViewDidEndDecelerating:(UIScrollView *)sender
{
    if (sender.contentOffset.x < scrollViewWidth) {
        [sender setContentOffset:CGPointMake( (outfitCount) * scrollViewWidth, 0) animated:NO];
    }
    else if (sender.contentOffset.x > (outfitCount) * scrollViewWidth) {
        [sender setContentOffset:CGPointMake(scrollViewWidth, 0) animated:NO];
    }
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end