关于iOS开发property with 'retain(or strong)' attribute must be of object type

Xcode的#import比#include的好处是解决多重包含的问题，遇到了相互包含头文件的问题

property with 'retain(or strong)' attribute must be of object type”

解决方案就是在出错头文件中实现

@class 文件名;便可解决例如

#import "BaseViewModelService.h"

#import "NavigationImpl.h"

@class NavigationImpl;

@interface BaseViewModel : NSObject

@property(nonatomic,strong) NavigationImpl *naviImpl;