(九十三)蓝牙的基本使用

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];
要遵循UINavigationControllerDelegate,GKPeerPickerControllerDelegate协议。

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
    
}
③要发送蓝牙数据,通过session的sendDataToAllPeers:::实现,其中withDataMode用于选择是可靠传输还是不可靠传输,类似TCP和UDP,下面的代码演示了发送一张图片的过程。

- (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

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