Category with property.

UIView+MyClass.m

#import <objc/runtime.h>

@interface UIView (MyClass)

@property (strong, nonatomic, readwrite, setter = my_setProperty:) NSObject *my_propery;

@end

static const char kProperty;

@implementation UIView (MyClass)

@dynamic my_property;

- (NSObject *)my_property {
    return objc_getAssociatedObject(self, &kProperty);
}

- (void)sc_setProperty:(NSObject *)my_property {
    objc_setAssociatedObject(self, &kProperty, my_property, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

@end