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

UIImageView 속성에 할당된 값이 없습니다

Answer 2

UIImageView를 표시할 수 있나요? 강함으로 바꾸면 어떨까요?

또한, scrollView의 contentSize는 이미지 크기로 설정됩니다.

Answer 3

scrollView가 초기화되지 않았습니다...