蓝牙实现对等网络连接 <GameKit/GameKit.h>

/*
 1.设置UI界面
 2.引入框架
 3.点击选择照片
 4.连接蓝牙设备
 5.实现蓝牙的代理方法
 6.发送照片
 */

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

@interface ViewController ()<UINavigationControllerDelegate, UIImagePickerControllerDelegate, GKPeerPickerControllerDelegate>

@property (nonatomic, strong) UIImageView *imgView;
@property (nonatomic, strong) UIButton *selectImgBtn;
@property (nonatomic, strong) UIButton *connectionDeviceBtn;
@property (nonatomic, strong) UIButton *sendImgBtn;
@property (nonatomic, strong) GKSession *seccion; // first deprecated in iOS 7.0 

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    _imgView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 20, self.view.bounds.size.width - 20, self.view.bounds.size.width - 20)];
    _imgView.backgroundColor = [UIColor lightGrayColor];
    [self.view addSubview:_imgView];

    _selectImgBtn = [UIButton buttonWithType:UIButtonTypeSystem];
    _selectImgBtn.frame = CGRectMake(10, CGRectGetMaxY(_imgView.frame) + 30, 60, 30);
    [_selectImgBtn setTitle:@"选择照片" forState:UIControlStateNormal];
    [self.view addSubview:_selectImgBtn];
    [_selectImgBtn addTarget:self action:@selector(clickSelectImgBtnAction) forControlEvents:UIControlEventTouchUpInside];

    _connectionDeviceBtn = [UIButton buttonWithType:UIButtonTypeSystem];
    _connectionDeviceBtn.frame = CGRectMake(0, 0, 60, 30);
    CGPoint p = CGPointMake(self.view.center.x, _selectImgBtn.center.y);
    _connectionDeviceBtn.center = p;
    [_connectionDeviceBtn setTitle:@"连接设备" forState:UIControlStateNormal];
    [self.view addSubview:_connectionDeviceBtn];
    [_connectionDeviceBtn addTarget:self action:@selector(clickConnectionDeviceBtnAction) forControlEvents:UIControlEventTouchUpInside];

    _sendImgBtn = [UIButton buttonWithType:UIButtonTypeSystem];
    _sendImgBtn.frame = CGRectMake(self.view.bounds.size.width - 70, CGRectGetMinY(_selectImgBtn.frame), 60, 30);
    [_sendImgBtn setTitle:@"发送照片" forState:UIControlStateNormal];
    [self.view addSubview:_sendImgBtn];
    [_sendImgBtn addTarget:self action:@selector(clickSendImgBtnAction) forControlEvents:UIControlEventTouchUpInside];
}

// 选择图片
- (void)clickSelectImgBtnAction {

    // 0.判断照片是否可用
    if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {

        return;
    }
    // 1.创建控制器
    UIImagePickerController *ipc = [UIImagePickerController new];
    // 2.设置图片源
    ipc.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    // 3.设置代理
    ipc.delegate = self;
    // 4.显示控制器
    [self presentViewController:ipc animated:YES completion:nil];

}

// 连接设备
- (void)clickConnectionDeviceBtnAction {

    // 1.创建控制器
    GKPeerPickerController *pic = [GKPeerPickerController new];  // first deprecated in iOS 7.0
    // 2.连接设备获取数据
    pic.delegate = self;
    // 3.显示控制器
    [pic show];
}

// 发送图片
- (void)clickSendImgBtnAction {

    // 0.需要一个data对象，把图片转化成data数据
    // CGFloat compressionQuality 精度，压缩比
    NSData *data = UIImageJPEGRepresentation(self.imgView.image, 0.2);
    // 1.通过session发送数据
    /*
     数据报（数据包，小块）
     GKSendDataReliable, 网络数据发送有误的时候，可以保证消息按照发送的顺序到达
     GKSendDataUnreliable 只发一次
     */
    [self.seccion sendDataToAllPeers:data withDataMode:GKSendDataReliable error:nil]; // first deprecated in iOS 7.0

} 

#pragma 相册的代理 - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {

　　NSLog(@"--info-- = %@", info); 　　UIImage *image = info[UIImagePickerControllerOriginalImage]; 　　_imgView.image = image; 　　[picker dismissViewControllerAnimated:YES completion:nil]; } 

#pragma mark - GKPeerPickerControllerDelegate - (void)peerPickerController:(GKPeerPickerController *)picker didConnectPeer:(NSString *)peerID toSession:(GKSession *)session { 

　　self.seccion = session; 

　　// 1.设置session会话，Handler（句柄，类似代理）  　　[session setDataReceiveHandler:self withContext:nil]; 

　　// 2.控制器的移除  　　[picker dismiss]; } 

// 从setDataReceiveHandler里面找出来 - (void)receiveData:(NSData *)data formPeer:(NSString *)peer inSession:(GKSession *)session context:(void *)context { 

　　UIImage *image = [UIImage imageWithData:data]; 　　_imgView.image = image; }

原文地址：https://www.cnblogs.com/xuzb/p/8963753.html