[Code Note] Click the plus sign to add a bookshelf, click the minus sign to reduce the bookshelf, And the minus sign to the bookshelf

[Code Note] Click the plus sign to add a bookshelf, click the minus sign to reduce the bookshelf, And the minus sign to the bookshelf

I ,.

2. Engineering Drawing.

3. Code.

ReaderViewController. h

#import <UIKit/UIKit.h>

@interface ReaderViewController : UIViewController
<UIScrollViewDelegate>
{
    UIScrollView *scrollView;
}
@property(nonatomic,strong) UIScrollView *scrollView;;
-(void)add;
-(void)dele;
-(void)reloadView;

@end

 

ReaderViewController. m

#import "ReaderViewController.h"

#define ImageHeight 120
static int num = 0;

@interface ReaderViewController ()

@end


@implementation ReaderViewController

-(id) initWithNibName: (NSString *) nibNameOrNil bundle: (NSBundle *) nibBundleOrNil
{
    self = [super initWithNibName: nibNameOrNil bundle: nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

-(void) viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    // font color
    self.navigationController.navigationBar.tintColor = [UIColor colorWithRed: 248.0 / 255.0 green: 172.0 / 255.0 blue: 37.0 / 255.0 alpha: 1.0];
    // Navigation bar background image
    [self addBackgroundView: @ "1.png"];
    
    // left delete button
    UIBarButtonItem * rightBarButton = [[UIBarButtonItem alloc]
                                       initWithTitle: @ "delete"
                                       style: UIBarButtonItemStyleBordered
                                       target: self
                                       action: @selector (dele)];
    // Add button on the right
    UIBarButtonItem * leftBarButton = [[UIBarButtonItem alloc]
                                      initWithBarButtonSystemItem: UIBarButtonSystemItemAdd
                                      target: self
                                      action: @selector (add)];
    
    self.navigationItem.rightBarButtonItem = rightBarButton;
    self.navigationItem.leftBarButtonItem = leftBarButton;
    
    // scrollerView
    scrollView = [[UIScrollView alloc] initWithFrame: CGRectMake (0, 0, 320, 416)];
    scrollView.contentSize = CGSizeMake (320,480);
    
    // Set the background color
    UIImage * backimg = [UIImage imageNamed: @ "3.png"];
    UIImageView * backview = [[UIImageView alloc] initWithImage: backimg];
    backview.frame = CGRectMake (0, 0, 320, 480);
    [self.view addSubview: backview];
    
    [self.view addSubview: scrollView];
    // Refresh the interface
    [self reloadView];

}
// Title on the navigation bar
-(void) addBackgroundView: (NSString *) image {
    
    UIImageView * imgView = [[UIImageView alloc] initWithImage: [UIImage imageNamed: image]];
    imgView.frame = CGRectMake (0, 0, 320, 44);
    [self.navigationController.navigationBar addSubview: imgView];
    
    UILabel * title = [[UILabel alloc] initWithFrame: CGRectMake ((320-150) / 2, 0, 150, 44)];
    [title setText: @ "书架"];
    [title setTextColor: [UIColor whiteColor]];
    [title setTextAlignment: NSTextAlignmentCenter];
    [title setShadowColor: [UIColor grayColor]];
    [title setBackgroundColor: [UIColor clearColor]];
    [title setFont: [UIFont boldSystemFontOfSize: 20.0]];
    [self.navigationController.navigationBar addSubview: title];
}

// Add a bookshelf
-(void) add {
    
    num ++;
    
    UIImage * backimg = [UIImage imageNamed: @ "2.png"];
    UIImageView * backview = [[UIImageView alloc] initWithImage: backimg];
    backview.frame = CGRectMake (0, (num-1) * ImageHeight, 320, ImageHeight);
    backview.tag = num + 100;
    
    [scrollView addSubview: backview];
    
    if (num> 3) {
        scrollView.contentSize = CGSizeMake (320, num * ImageHeight);
    }
}

// delete a bookshelf
-(void) dele {
    
    if (num <= 0) {
        return;
    }
    
    for (UIView * view in scrollView.subviews) {
        if (view.tag == (num + 100))
            [view removeFromSuperview];
    }
    
    num--;
    
    if (num> 3) {
        scrollView.contentSize = CGSizeMake (320, num * ImageHeight);
    }
    
}

// Main interface initialization
-(void) reloadView {
    
    NSLog (@ "reloadView");
    // Iterate through all sub-interfaces of the current interface and delete the sub-interfaces clean
    for (UIView * view in scrollView.subviews) {
        [view removeFromSuperview];
    }
    
    scrollView.showsVerticalScrollIndicator = NO;
    scrollView.showsHorizontalScrollIndicator = NO;
    scrollView.delegate = self;
    [scrollView setScrollEnabled: YES];
    
}

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