蓝牙在GameKit框架中实现，可以实现文件传递和游戏通信等，蓝牙的缺点是不能得到文件传输的进度，因此不宜传输大文件。
使用蓝牙的一般步骤如下：
①创建蓝牙设备拾取器，类似于图片拾取器，通过代理方法获取拾取到的设备，调用show方法来显示拾取器。
GKPeerPickerController *peerC = [[GKPeerPickerController alloc] init];
peerC.delegate = self;
[peerC show];②通过代理方法获取拾取到的设备，存储这个会话，然后dismiss拾取器视图，记得要存储会话，注意为了接收数据，应该调用会话的setDataReceiveHandler::方法：
- (void)peerPickerController:(GKPeerPickerController *)picker didConnectPeer:(NSString *)peerID toSession:(GKSession *)session{_session = session;// 设置谁来处理数据[session setDataReceiveHandler:self withContext:NULL];[picker dismiss];}接收数据的方法既不是代理，也不是通知，因此必须和帮助文档中写的一样，方法如下：
- (void) receiveData:(NSData *)data fromPeer:(NSString *)peer inSession: (GKSession *)session context:(void *)context{// data就是接收到的二进制数据}- (IBAction)send:(id)sender {NSData *data = UIImagePNGRepresentation(_imageView.image);NSError *err = nil;// 可靠连接可以保证一定送到，不可靠只负责发送[_session sendDataToAllPeers:data withDataMode:GKSendDataUnreliable error:&err];if (err) {NSLog(@"%@",err);}}【实例】
下面的例子演示了一个发送图片的例程，有一张图片imageView，三个按钮，分别是连接(connect方法)、选择(choosePic)、发送(send)，点击选择从照片图库中选择一张图片，点击连接建立会话，点击发送将图片通过会话发送出去。
//
// ViewController.m
// 蓝牙基本使用
//
// Created by 11 on 7/27/15.
// Copyright (c) 2015 soulghost. All rights reserved.
//#import "ViewController.h"
#import <GameKit/GameKit.h>@interface ViewController () <UIImagePickerControllerDelegate,UINavigationControllerDelegate,GKPeerPickerControllerDelegate>@property (weak, nonatomic) IBOutlet UIImageView *imageView;
@property (weak, nonatomic) GKSession *session;@end@implementation ViewController- (void)viewDidLoad {[super viewDidLoad];}- (IBAction)connect:(id)sender {// 创建蓝牙设备选择器View，设置代理并且显示、GKPeerPickerController *peerC = [[GKPeerPickerController alloc] init];peerC.delegate = self;[peerC show];}
- (IBAction)choosePic:(id)sender {if(![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeSavedPhotosAlbum]){NSLog(@"图库不可用");return;}UIImagePickerController *imgPickerC = [[UIImagePickerController alloc] init];imgPickerC.delegate = self;imgPickerC.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;[self presentViewController:imgPickerC animated:YES completion:nil];}
- (IBAction)send:(id)sender {NSData *data = UIImagePNGRepresentation(_imageView.image);NSError *err = nil;// 可靠连接可以保证一定送到，不可靠只负责发送[_session sendDataToAllPeers:data withDataMode:GKSendDataUnreliable error:&err];if (err) {NSLog(@"%@",err);}}- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{//NSLog(@"%@",info);UIImage *image = info[UIImagePickerControllerOriginalImage];_imageView.image = image;[self imagePickerControllerDidCancel:picker];}- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{[picker dismissViewControllerAnimated:YES completion:nil];
}- (void)peerPickerController:(GKPeerPickerController *)picker didConnectPeer:(NSString *)peerID toSession:(GKSession *)session{_session = session;// 设置谁来处理数据[session setDataReceiveHandler:self withContext:NULL];[picker dismiss];}// 通过看setDataReceiveHandler的帮助得到，只要实现了即可
// 接收到其他设备传来的数据时调用
- (void) receiveData:(NSData *)data fromPeer:(NSString *)peer inSession: (GKSession *)session context:(void *)context{UIImage *image = [UIImage imageWithData:data];_imageView.image = image;}@end
