When trying to set custom background image and remove the default one point height shadow image, I have to set a UIImage instance without content == [UIImage new], but in - (BOOL)convertValue:(id)value imageHandler:(void (^)(UIImage ))imageHandler codeHandler:(void (^)(NSString ))codeHandler; if the value is @"", [UIImage imageNamed:value] will return nil so the shadow image can not be removed.
"UINavigationBar": { "backgroundImage:default": "nav_bg", "shadowImage": "", }
When trying to set custom background image and remove the default one point height shadow image, I have to set a UIImage instance without content == [UIImage new], but in - (BOOL)convertValue:(id)value imageHandler:(void (^)(UIImage ))imageHandler codeHandler:(void (^)(NSString ))codeHandler; if the value is @"", [UIImage imageNamed:value] will return nil so the shadow image can not be removed.