如果以编程方式创建，则无法访问UIImageView

问题描述

如果我通过Storyboard创建UIImageView并将其作为@property添加到ViewController.h中，则可以通过[self UIImageView]或self.UIImageView从ViewController.m中的任何位置访问该UIImageView. /p>

但是，如果我通过viewDidLoad以编程方式创建UIImageView，如下所示，我似乎会失去从viewDidLoad外部访问它的能力.

UIImageView *prevImgView = [[UIImageView alloc] init];
UIImageView *currImgView = [[UIImageView alloc] init];
UIImageView *nextImgView = [[UIImageView alloc] init];

NSArray *imageViews = [NSArray arrayWithObjects:prevImgView, currImgView, nextImgView, nil];

UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
[self.view addSubview: scrollView];

CGRect cRect = scrollView.bounds;
UIImageView *cView;

for (int i=0; i<imageViews.count; i++) {
    cView = [imageViews objectAtIndex:i];
    cView.frame = cRect;
    [scrollView addSubview:cView];
    cRect.origin.x += cRect.size.width;
}

因此，如果以后要修改从viewDidLoad创建的任何UIImageView中显示的图像，我似乎无法访问它.有人知道我在做什么错吗?

解决方案

您需要在头文件中创建UIImageView，然后在其余的视图中将其使用.不过，您需要将其添加到viewDidLoad中的视图中.

         Header
         UIImageView *image;

         Main // ViewDidLoad
         image = [UIImageView alloc] .....
         [self.view addSubView image];


         Main Function .....
         [image setImage ....

If I create a UIImageView via Storyboard and add it as a @property into a ViewController.h, I can access that UIImageView from anywhere in the ViewController.m via [self UIImageView] or self.UIImageView.

But If I create the UIImageView programmatically from viewDidLoad as you see below, I seem to lose the ability to access it from outside viewDidLoad.

UIImageView *prevImgView = [[UIImageView alloc] init];
UIImageView *currImgView = [[UIImageView alloc] init];
UIImageView *nextImgView = [[UIImageView alloc] init];

NSArray *imageViews = [NSArray arrayWithObjects:prevImgView, currImgView, nextImgView, nil];

UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
[self.view addSubview: scrollView];

CGRect cRect = scrollView.bounds;
UIImageView *cView;

for (int i=0; i<imageViews.count; i++) {
    cView = [imageViews objectAtIndex:i];
    cView.frame = cRect;
    [scrollView addSubview:cView];
    cRect.origin.x += cRect.size.width;
}

So later on if I want to modify the image that is being displayed in any one of the UIImageView I've created from viewDidLoad, I can't seem to access it. Does anyone know what I'm doing wrong?

解决方案

You would need to create your UIImageView in your header file and then it would be available throughout the rest of the view. You will need to add it to the view in viewDidLoad though.

         Header
         UIImageView *image;

         Main // ViewDidLoad
         image = [UIImageView alloc] .....
         [self.view addSubView image];


         Main Function .....
         [image setImage ....

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