Question

我正在构建一个内部滚动的应用程序。简而言之，这是我的配置：

1）class_1：使用集合视图列出一组内部元素（类似于相机行）的视图

2）class_2：由class_1调用的模态视图，其中我显示了所选的每个单数元素（来自class_1）。在同一个类中，我还实现了所有元素的水平滚动

3）class_3：一个简单的viewcontroller，里面有一个imageview，里面将包含我将在class_2中显示的元素

运行我的应用程序看起来像class_3没有添加为class_2的子视图，我尝试加载的所有单个内容都不可见。

以下是我的class_2代码

接口：

#import <UIKit/UIKit.h> 
#import "class_3.h"

@interface class_2 : UIViewController 

@property (strong, nonatomic) IBOutlet UIPageControl *pageControl;
@property (strong, nonatomic) IBOutlet UIScrollView *scrollView;
@property (weak, nonatomic) NSArray *imageList;

@end

实现：

@interface class_2 () {
    NSMutableArray *_viewControllers;
}

    - (void)loadScrollViewWithImage:(NSUInteger)indexImage;

@end

@implementation class_2

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

- (void)viewDidLoad {
    [super viewDidLoad];

    // _imageList is passed from class_1 when I call class_2. Contains an array of images
    self.pageControl.numberOfPages = [_imageList count];
    self.pageControl.currentPage = 0;

    // I store inside an array N objects as the number f images I have to show. At the beginning the array has only null objects, then it will contains the views based on the images I have scrolled.
    //I am storying my images inside a view because maybe I will show more controls and not just the image. It will be much easier manage them.
    _viewControllers = [[NSMutableArray alloc] init];
    for (NSUInteger i = 0; i < [_imageList count]; i++) {
        [_viewControllers addObject:[NSNull null]];
    }

    // I set some properties of my scrollview defined as outlet
    self.scrollView.frame = CGRectMake(0, 0, 320, 345);
    self.scrollView.contentSize = CGSizeMake(CGRectGetWidth(self.scrollView.frame) * [_imageList count], CGRectGetHeight(self.scrollView.frame));
    self.scrollView.pagingEnabled = YES;
    // this is set to NO, I switched to YES just now for debug (at least I can see how big the area is since there are no images visible)
    self.scrollView.showsHorizontalScrollIndicator = YES;
    self.scrollView.showsVerticalScrollIndicator = NO;
    self.scrollView.scrollsToTop = NO;
    self.scrollView.delegate = self;

    // for testing now I always take the first and second elements of my array. I load both so when I move from the first image to the second is already there and there is no gap/flashing effect
    [self loadScrollViewWithImage:0];
    [self loadScrollViewWithImage:1];
}

#pragma mark - Private methods

- (void)loadScrollViewWithImage:(NSUInteger)indexImage {
    // I scrolled until the last image, from here I can only go back
    if (indexImage >= [_imageList count])
        return;

    // I replace the placeholder (null) object
    class_3 *controller = [_viewControllers objectAtIndex:indexImage];
    if ((NSNull *)controller == [NSNull null]) {
        controller = [[class_3 alloc] init];
        [_viewControllers replaceObjectAtIndex:indexImage withObject:controller];
    }

    // I add the controller's view to the scroll view - in case this is the first time I'm scrolling this image
    if (controller.view.superview == nil) {
        // I set my controller frame as the scrollview works as container
        CGRect frame = self.scrollView.frame;
        frame.origin.x = CGRectGetWidth(frame) * indexImage;
        frame.origin.y = 0;
        controller.view.frame = frame;

        // I finally add my viewcontroller as child of my superview and subview of the scrollview
        [self addChildViewController:controller];
        [self.scrollView addSubview:controller.view];
        [controller didMoveToParentViewController:self];

        // I set an image corrisponding with the element selected from class_1
        controller.imageView.image = [_imageList objectAtIndex:indexImage]

        // I also tried with a fake image...just in case. No one of them is visible
        //controller.imageView.image = [UIImage imageNamed:@"tempPhoto"];
    }
}

我的class_3是一个viewcontroller，它只承载一个图像视图，该图像视图应该填充之前选择的相应图像。页面控制器用于显示我滚动的位置（letf / right）以及有多少元素。使用scrollview进行滚动操作。这是我的class_3定义

接口：

#import <UIKit/UIKit.h>
#import "class_3.h"

@interface class_3 : UIViewController

@property (strong, nonatomic) IBOutlet UIImageView *imageView;

@end

实施（没有什么真正令人印象深刻）

#import "class_3.h"

@interface class_3 ()

@end

@implementation class_3

- (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.

    self.imageView.image = [UIImage imageNamed:@"tempPhoto"];
}

@end

我错过了什么？

TNX

Answer 1

您的class_3应该是UIView，而不是UIViewController子类。见here

添加UIViewController作为UIScrollView的子视图

1 个答案: