ios - 请教：scrollView中无法用viewForZoomingInScrollView方法缩放

Question

按照教程，在scrollView中使用viewForZoomingInScrollView方法进行图片缩放，编译成功，但是无法缩放。

代码如下：

#import "ViewController.h"

@interface ViewController () <UIScrollViewDelegate>

@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;
@property (weak, nonatomic) UIImageView *imageView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"minion"]];
    
    [self.scrollView addSubview:imageView];
    self.scrollView.contentSize = imageView.image.size;
    
    self.scrollView.delegate = self;
    self.scrollView.maximumZoomScale = 3.0;
    self.scrollView.minimumZoomScale = 0.2;

}

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{
    return self.imageView;
}

Answer 1

The property UIImageView has no value assigned

Answer 2

Can UIImageView be displayed? What about changing it to strong?

In addition, the contentSize of scrollView is set to the size of the image. How big is the size of the image?

Answer 3

ScrollView is not initialized...