fix: UIImagePickerController cannot move editing box

UIImagePickerController+fixCannotMoveEditingBox.h

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface UIImagePickerController (FixCannotMoveEditingBox)

- (void)fixCannotMoveEditingBox;

@end

NS_ASSUME_NONNULL_END

UIImagePickerController+fixCannotMoveEditingBox.m

#import "UIImagePickerController+fixCannotMoveEditingBox.h"
#import <objc/runtime.h>

@interface WeakObjectContainer : NSObject
@property (nonatomic, readonly, weak) id object;
@end

@implementation WeakObjectContainer
- (instancetype) initWithObject:(id)object
{
    if (!(self = [super init]))
        return nil;
    
    _object = object;
    
    return self;
}
@end

@implementation UIImagePickerController (FixCannotMoveEditingBox)

// MARK: - Create a weak stored property in extension
- (id)weakObjectForKey:(const void*)key {
    WeakObjectContainer *container = objc_getAssociatedObject(self, key);
    return [container object];
}

- (void)setWeakObject:(id)object forKey:(const void*)key {
    WeakObjectContainer *container = [[WeakObjectContainer alloc] initWithObject:object];
    objc_setAssociatedObject(self, key, container, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

// MARK: - Create a weak property for scrollView
- (UIScrollView *)scrollView {
    return [self weakObjectForKey:_cmd];
}

- (void)setScrollView:(UIScrollView *)scrollView {
    [self setWeakObject:scrollView forKey:@selector(scrollView)];
}

// MARK: - Create a weak property for cropView
- (UIView *)cropView {
    return [self weakObjectForKey:_cmd];
}

- (void)setCropView:(UIView *)cropView {
    [self setWeakObject:cropView forKey:@selector(cropView)];
}

// MARK: - Fix cannot move editing box
- (void)fixCannotMoveEditingBox {
    if (self.sourceType == UIImagePickerControllerSourceTypeCamera &&
        (!self.scrollView || !self.cropView)) {
        UIView *view = [self view];
        self.scrollView = [self findScrollView:view];
        self.cropView = [self findCropView:view];
        
        if (self.scrollView && self.cropView) {
            CGFloat top = self.cropView.frame.origin.y;
            CGFloat bottom = ({
                self.scrollView.frame.size.height - self.cropView.frame.size.height - self.cropView.frame.origin.y;
            });
            self.scrollView.contentInset = UIEdgeInsetsMake(top, 0, bottom, 0);
            self.scrollView.contentOffset = CGPointMake(0, -top+10);
        }
    }
    
    __weak typeof(self) weakself = self;
    dispatch_time_t delay = dispatch_time(DISPATCH_TIME_NOW, 0.1 * NSEC_PER_SEC);
    dispatch_after(delay, dispatch_get_main_queue(), ^(void){
        __strong typeof(weakself) strongself = weakself;
        [strongself fixCannotMoveEditingBox];
    });
}

- (UIScrollView *)findScrollView:(UIView *)view {
    if ([view isKindOfClass:[UIScrollView class]]) {
        return (UIScrollView *)view;
    }
    for (UIView *subview in [view subviews]) {
        UIScrollView *view = [self findScrollView:subview];
        if (view) {
            return view;
        }
    }
    return nil;
}

- (UIView *)findCropView:(UIView *)view {
    CGFloat width = [[UIScreen mainScreen] bounds].size.width;
    CGSize size = [view frame].size;
    if (size.width == width && size.height == width) {
        return view;
    }
    for (UIView *subview in [view subviews]) {
        UIView *view = [self findCropView:subview];
        if (view) {
            return view;
        }
    }
    return nil;
}

@end