關於iOS開發property with 'retain(or strong)' attribute must be of object type

Xcode的#import比#include的好處是解決多重包含的問題，遇到了相互包含頭文件的問題

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

解決方案就是在出錯頭文件中實現

@class 文件名;便可解決例如

#import "BaseViewModelService.h"

#import "NavigationImpl.h"

@class NavigationImpl;

@interface BaseViewModel : NSObject

@property(nonatomic,strong) NavigationImpl *naviImpl;