出现 Assigning to 'id<UINavigationControllerDelegate,UIImagePickerControllerDelegate>' from incompatible type 'ManageMessageViewController' 警告

当调用UIImagePickerController时，在进行委托定义是提示Assigning to 'id<UINavigationControllerDelegate,UIImagePickerControllerDelegate>' from incompatible type 'ManageMessageViewController'，可以在声明类所遵循的协议中加入UINavigationControllerDelegate即可解决