MacOS：10.14，Xcode：11.0

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1、随意创建一个工程，可以是App project
Xcode -> File -> New -> Project... -> macOS -> Application -> App -> click Next
填写Product Name(XPCDemo) -> 选择或者不选择Team账号 -> click Next -> click create， 创建一个工程

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2、创建xpc service

选中project -> 显示targets栏 -> 点击"+"号

选择macOS -> 筛选框中输入xpc -> 选择XPC Service -> click Next


填写Product Name -> 设置 Bundle Identifer -> click Finish完成创建
 
 

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3、检查和设置
创建完成后，检查下TARGETS -> XPCDemo -> Build Phases中，有增加一项 Embed XPC Services
这个功能现在在我的Xcode 11.0是自动添加的，但很早以前的版本好像还要自己添加才行


检查或设置xpc的bundle identifer，在调用xpc时使用

 

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4、文件说明：
XPC 创建后，在工程中会生成4个文件，

XPCServiceProtocol.h声明一些函数，

// XPCServiceProtocol.h文件
#import <Foundation/Foundation.h>@protocol XPCServiceProtocol
- (void)upperCaseString:(NSString *)aString withReply:(void (^)(NSString *))reply;    
@end

XPCService.h声明继承了协议，

// XPCService.h文件
#import <Foundation/Foundation.h>
#import "XPCServiceProtocol.h"
@interface XPCService : NSObject <XPCServiceProtocol>
@end

XPCService.m中实现这些协议方法

// XPCService.m文件
#import "XPCService.h"@implementation XPCService
// XPCServiceProtocol.h中声明的方法的实现
- (void)upperCaseString:(NSString *)aString withReply:(void (^)(NSString *))reply {NSString *response = [aString uppercaseString];reply(response);
}@end

这个函数是xcode自动生成的示例代码，可直接用来测试。在main.m文件中也有很多代码，都是自动生成的，暂且不管
调用XPC的时候，调用Protocol中声明的方法，Protocol是内外使用方法的桥梁

 

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5、XPC启动和方法调用
在XPCServiceProtocol.h中也给出了如何使用xpc的一个示例代码
示例中给出了建立连接、运行方法、清除连接的方法

/*To use the service from an application or other process, use NSXPCConnection to establish a connection to the service by doing something like this:_connectionToService = [[NSXPCConnection alloc] initWithServiceName:@"com.company.XPCService"];_connectionToService.remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol(XPCServiceProtocol)];[_connectionToService resume];Once you have a connection to the service, you can use it like this:[[_connectionToService remoteObjectProxy] upperCaseString:@"hello" withReply:^(NSString *aString) {// We have received a response. Update our text field, but do it on the main thread.NSLog(@"Result string was: %@", aString);}];And, when you are finished with the service, clean up the connection like this:[_connectionToService invalidate];
*/

storyboard -> View Controller Scene -> 添加button -> ctrl+鼠标，将button在ViewController中建立个action连接
ViewController.h中引入头文件：

// ViewController.h文件
#import <Cocoa/Cocoa.h>
#import "XPCServiceProtocol.h"
#import "XPCService.h"
@interface ViewController : NSViewController@end

ViewController.m文件内容:

// ViewController.m文件
#import "ViewController.h"
@interface ViewController(){NSXPCConnection *_connectionToService; //私有变量
}
@end@implementation ViewController- (void)viewDidLoad {[super viewDidLoad];//建立xpc连接并启动_connectionToService = [[NSXPCConnection alloc] initWithServiceName:@"com.company.XPCService"];_connectionToService.remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol(XPCServiceProtocol)];[_connectionToService resume];
}- (void)setRepresentedObject:(id)representedObject {[super setRepresentedObject:representedObject];// Update the view, if already loaded.
}
- (IBAction)XPCTest:(id)sender {// XPC中运行方法[[_connectionToService remoteObjectProxy] upperCaseString:@"hello" withReply:^(NSString *aString) {NSLog(@"Result string was: %@", aString);}];
}
@end

执行结果(XPC执行方法upperCaseString，输出结果)：

 
 

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github XPCDemo：https://github.com/auspark/XPCDemo

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Apple Documentation：

Apple XPC
Creating XPC Services
Efficient Design with XPC Videos
Kernel and Device Drivers Layer