为了屏蔽各种中介的电话骚扰，最近安装了腾讯手机管家，安装完成后，设置“骚扰拦截”功能时，App提示需要点击“设置--->电话--->来电阻止与身份识别--->勾选App提供的"黄页"、“电话识别”和“电话拦截”。

了解过苹果沙盒机制的朋友都知道，一般在App中要访问到其他 App/硬件（地理位置，相册，通讯录，话筒） 内容，会通过系统弹窗询问用户，必须要获取管理员许可才行，比如这样：

那么上面的“来电阻止和身份识别”功能又是什么东东呢？

CallKit.framework

苹果在iOS 10中为我们带来了callkit.framework，当我们语言通话显示系统界面时，它允许我们对来电号码进行识别、过滤、标记、阻止等操作。目前国内垃圾电话、骚扰电话、诈骗电话不胜其烦，针对iPhone全球第二大市场，苹果今次顺势而为推出开放接口，也算是人心所向。有兴趣的朋友可以通过官方文档说明了解callkit.framework。

下面我们尝试来写一个demo，让自己App出现在电话“设置--->电话--->来电阻止与身份识别 列表中，实现来电过滤功能

1、新建一个iOS工程

2、完成后，新建target：点击"+"---> 选择iOS，Call Directory Extension， 输入名称如：CallFirewall，一路next，选择“Activate”

3、完成上面操作，可以看到在项目工程中，自动生成了下面几个文件。

4、打开文件 CallDirectoryHandler.h 和 CallDirectoryHandler.m，使用注意事项，请参照代码注释：

//
//  CallDirectoryHandler.h
//  CallFirewall
//
//  Created by lvxiangan on 26/07/2017.
//  Copyright © 2017 lvxiangan. All rights reserved.
//
 
#import <Foundation/Foundation.h>
#import <CallKit/CallKit.h>
 
@interface CallDirectoryHandler : CXCallDirectoryProvider
 
@end

//
//  CallDirectoryHandler.m
//  CallFirewall
//
//  Created by lvxiangan on 26/07/2017.
//  Copyright © 2017 lvxiangan. All rights reserved.
//
 
#import "CallDirectoryHandler.h"
 
@interface CallDirectoryHandler () <CXCallDirectoryExtensionContextDelegate>
@end
 
@implementation CallDirectoryHandler
 
// 请求前检查
- (void)beginRequestWithExtensionContext:(CXCallDirectoryExtensionContext *)context {
    context.delegate = self;
 
    if (![self addBlockingPhoneNumbersToContext:context]) {
        NSLog(@"Unable to add blocking phone numbers");
        NSError *error = [NSError errorWithDomain:@"CallDirectoryHandler" code:1 userInfo:nil];
        [context cancelRequestWithError:error];
        return;
    }
    
    if (![self addIdentificationPhoneNumbersToContext:context]) {
        NSLog(@"Unable to add identification phone numbers");
        NSError *error = [NSError errorWithDomain:@"CallDirectoryHandler" code:2 userInfo:nil];
        [context cancelRequestWithError:error];
        return;
    }
    
    [context completeRequestWithCompletionHandler:nil];
}
 
 
// 来电阻止
- (BOOL)addBlockingPhoneNumbersToContext:(CXCallDirectoryExtensionContext *)context {
    // Retrieve phone numbers to block from data store. For optimal performance and memory usage when there are many phone numbers,
    // consider only loading a subset of numbers at a given time and using autorelease pool(s) to release objects allocated during each batch of numbers which are loaded.
    //
    // Numbers must be provided in numerically ascending order.
    CXCallDirectoryPhoneNumber phoneNumbers[] = { 14085555555, 18005555555 };
    NSUInteger count = (sizeof(phoneNumbers) / sizeof(CXCallDirectoryPhoneNumber));
 
    for (NSUInteger index = 0; index < count; index += 1) {
        CXCallDirectoryPhoneNumber phoneNumber = phoneNumbers[index];
        [context addBlockingEntryWithNextSequentialPhoneNumber:phoneNumber];
    }
 
    return YES;
}
 
 
// 来电识别
- (BOOL)addIdentificationPhoneNumbersToContext:(CXCallDirectoryExtensionContext *)context {
    // Retrieve phone numbers to identify and their identification labels from data store. For optimal performance and memory usage when there are many phone numbers,
    // consider only loading a subset of numbers at a given time and using autorelease pool(s) to release objects allocated during each batch of numbers which are loaded.
    //
    // Numbers must be provided in numerically ascending order.
    CXCallDirectoryPhoneNumber phoneNumbers[] = { 18775555555, 18885555555 };
    NSArray<NSString *> *labels = @[ @"Telemarketer", @"Local business" ];
    NSUInteger count = (sizeof(phoneNumbers) / sizeof(CXCallDirectoryPhoneNumber));
 
    for (NSUInteger i = 0; i < count; i += 1) {
        CXCallDirectoryPhoneNumber phoneNumber = phoneNumbers[i];
        NSString *label = labels[i];
        [context addIdentificationEntryWithNextSequentialPhoneNumber:phoneNumber label:label];
    }
 
    return YES;
}
 
#pragma mark - CXCallDirectoryExtensionContextDelegate
 
// 添加黑名单或识别来电失败处理
- (void)requestFailedForExtensionContext:(CXCallDirectoryExtensionContext *)extensionContext withError:(NSError *)error {
    // An error occurred while adding blocking or identification entries, check the NSError for details.
    // For Call Directory error codes, see the CXErrorCodeCallDirectoryManagerError enum in <CallKit/CXError.h>.
    //
    // This may be used to store the error details in a location accessible by the extension's containing app, so that the
    // app may be notified about errors which occured while loading data even if the request to load data was initiated by
    // the user in Settings instead of via the app itself.
}
 
@end

同理，参照腾讯手机管家的做法，我们建多几个target，就会在“来电阻止与身份识别”中有多个选项。

这样，我们就可以根据自定义target用途，来编写不同功能的代码了。