要在iOS上创建音频单元扩展,需要混合使用C ++和Objective-C类。结果,我现在有了一个带有C ++对象作为其变量之一的Objective-C对象。
我希望C ++子对象能够将某些状态更改通知其Objective-C父/所有者。
用伪代码:
void cppChildObject::callMom() {
objectiveCParent::notificationMethod();
}
这有可能优雅吗?
最佳答案
这取决于定义优雅的方式...如果C ++类位于Objective-C ++文件(扩展名为.mm的文件)中,并且未由非C ++代码直接使用的C ++代码,则可以用相当优雅的方式实现Objective-C ++源文件。问题是C ++代码只有在Objective-C ++源文件中才能使用Objective-C类型。这是一个简单的示例,希望对您有所帮助。
Objective-C ++文件mylib.mm
(注意.mm扩展名):
#import "objcpp.h"
#import <stdio.h>
#import "cpp.h"
// A C++ class in an Objective-C++ file.
// This C++ class would not need to sub-class ParentNotifier, and ParentNotifier
// would not be needed at all if it were not for OutsiderCPP, which talks to its
// Objective-C parent through InsiderCPP.
class InsiderCPP : public ParentNotifie {
public:
InsiderCPP(MyClassOCPP * parent) : myParent(parent){}
void doSomething() {
callMom("To Mom from insider.");
}
void callMom(const char * msg) {
[myParent notificationMethod:msg];
}
private:
MyClassOCPP * __weak myParent;
};
@interface MyClassOCPP ()
@property InsiderCPP * insiderChild;
@property OutsiderCPP * outsiderChild;
@end
@implementation MyClassOCPP
-(id)init {
self.insiderChild = new InsiderCPP(self);
self.outsiderChild = new OutsiderCPP(self.insiderChild);
return self;
}
-(void)doWork {
self.insiderChild->doSomething();
self.outsiderChild->doSomething();
}
-(void)notificationMethod:(const char *)msg {
printf("Parent has been notified with: %s\n", msg);
}
-(void)dealloc {
delete self.insiderChild;
delete self.outsiderChild;
}
@end
这是对应的标题
objcpp.h
:#ifndef objcpp_h
#define objcpp_h
#import <Foundation/Foundation.h>
@interface MyClassOCPP : NSObject
-(id)init;
-(void)dealloc;
-(void)doWork;
-(void)notificationMethod:(const char*)msg;
@end
#endif
这是与Objective-C无关的“纯” C ++源文件(
mylib.cpp
):#include <stdio.h>
#include "cpp.h"
void OutsiderCPP::callMom(const char * m) {
myParent->callMom(m);
}
void OutsiderCPP::doSomething() {
callMom("To Mom from outsider.");
}
这是对应的标头(
cpp.h
):#ifndef cpp_h
#define cpp_h
class ParentNotifier
{
public:
virtual void callMom(const char *) = 0;
};
class OutsiderCPP
{
public:
OutsiderCPP(ParentNotifier * p) : myParent(p) {}
void doSomething();
void callMom(const char *);
private:
ParentNotifier * myParent;
};
#endif
请注意,此示例仅用于说明目的,并非生产质量。