iOS－Core Foundation框架到Foundation桥接的三种方式

温故知新、勤总结，才能生巧！这次总结一下 ：Core Foundation框架到Foundation桥接的三种方式

Foundation提供OC的基础类（像NSObject）、基本数据类型等。

Core Foundation框架 (CoreFoundation.framework) 是一组C语言接口，它们为iOS应用程序提供基本数据管理和服务功能；

XXX为OC的字符串

桥接方式一、

     
(__bridgeNSString *)(XXX);

桥接方式二、

   CFBridgingRelease(XXX)

桥接方式三、

   (__bridge_transferNSString*)
(XXX);

Core Foundation的内存管理：

     Core Foundation是一组C语言，ARC下，C语言的框架并不会自动释放；

     使用桥接方式一的时候，必须需要手动释放内存；

     
CFRelease(XXX);

     在使用桥接方式二、桥接方式三时，则会自动化释放内存；

举例说明：

    以一个获取通讯录联系人说明：

    首先导入通讯录的框架：

    1、#import<AddressBookUI/AddressBookUI.h>

        2、遵循代理；

3、实现相关代理方法

#import "ViewController.h"
#import <AddressBookUI/AddressBookUI.h>

@interface ViewController ()<ABPeoplePickerNavigationControllerDelegate>

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    ABPeoplePickerNavigationController *peopleVc = [[ABPeoplePickerNavigationController alloc] init];
    peopleVc.peoplePickerDelegate = self;
    [self presentViewController:peopleVc animated:YES completion:nil];
}

#pragma -mark ABPeoplePickerNavigationControllerDelegate
- (void)peoplePickerNavigationController:(ABPeoplePickerNavigationController*)peoplePicker didSelectPerson:(ABRecordRef)person{

//    桥接方式一
//    CFStringRef firstNameRef = ABRecordCopyValue(person, kABPersonSortByFirstName);
//    CFStringRef lastNameRef = ABRecordCopyValue(person, kABPersonSortByFirstName);
//
//    NSString *firstName = (__bridge NSString *)(firstNameRef);
//    NSString *lastName = (__bridge NSString *)(lastNameRef);
//    NSLog(@"%@  %@",firstName,lastName);
//
//    CFRelease(firstNameRef);
//    CFRelease(lastNameRef);

//    桥接方式二
//    CFStringRef firstNameRef = ABRecordCopyValue(person, kABPersonSortByFirstName);
//    CFStringRef lastNameRef = ABRecordCopyValue(person, kABPersonSortByFirstName);
//
//    NSString *firstName = CFBridgingRelease(firstNameRef);
//    NSString *lastName = CFBridgingRelease(lastNameRef);
//    NSLog(@"%@  %@",firstName,lastName);

//    桥接方式三
    CFStringRef firstNameRef = ABRecordCopyValue(person, kABPersonSortByFirstName);
    CFStringRef lastNameRef = ABRecordCopyValue(person, kABPersonSortByFirstName);

    NSString *firstName = (__bridge_transfer NSString *)(firstNameRef);
    NSString *lastName = (__bridge_transfer  NSString *)(lastNameRef);
    NSLog(@"%@  %@",firstName,lastName);

}
@end