iOS开发-CoreNFC实现NFC标签Tag读取功能

iOS开发-CoreNFC实现NFC标签Tag读取功能

一、NFC近场通信

近场通信（NFC）是一种无线通信技术，它使设备能够在不使用互联网的情况下相互通信。它首先识别附近配备NFC的设备。NFC常用于智能手机和平板电脑。

二、实现NFC标签Tag读取功能

在iOS中提供了CoreNFC来实现NFC标签Tag读取功能。主要使用的类是NFCTagReaderSession。
NFCTagReaderSession配置读取器会话的RF轮询；可以将多个选项“或”运算在一起。此选项会影响可能的NFC标签类型。同时需要实现delegate来实现扫描的回调。

NFCTagReaderSession初始化

 if (@available(iOS 13.0, *)) {
        if (NFCNDEFReaderSession.readingAvailable) {
            self.tagSession = [[NFCTagReaderSession alloc]
                                initWithPollingOption:(NFCPollingISO14443 | NFCPollingISO15693 | NFCPollingISO15693) delegate:self queue:dispatch_get_main_queue()];
            self.tagSession.alertMessage = @"读取卡片，请将卡片靠近手机";
            [self.tagSession beginSession]; //开始识别 弹出识别提示框
        }else{
            NSLog(@"NFC功能只支持iphone7以及iOS13.0以上设备");
        }
    }else{
        NSLog(@"NFC功能只支持iphone7以及iOS13.0以上设备");
    }
    

NFCNDEFReaderSessionDelegate的相关方法

• 识别结果的回调

-(void)readerSession:(NFCNDEFReaderSession *)session didDetectNDEFs:(NSArray *)messages API_AVAILABLE(ios(11.0))

• 错误回调

-(void)readerSession:(NFCNDEFReaderSession *)session didInvalidateWithError:(NSError *)error API_AVAILABLE(ios(11.0))

• 在Session无效时调用

• (void)tagReaderSession:(NFCTagReaderSession *)session didInvalidateWithError:(NSError *)error API_AVAILABLE(ios(13.0)) API_UNAVAILABLE(watchos, macos, tvos)

• 当NFC读取器会话变为Active时调用

• (void)tagReaderSessionDidBecomeActive:(NFCTagReaderSession *)session API_AVAILABLE(ios(13.0)) API_UNAVAILABLE(watchos, macos, tvos)

• 当读取器在轮询序列中检测到NFC标记时调用

• (void)tagReaderSession:(NFCTagReaderSession *)session didDetectTags:(NSArray<__kindof id> *)tags API_AVAILABLE(ios(13.0)) API_UNAVAILABLE(watchos, macos, tvos)

实现识别NFC标签Tag完整代码如下

#import "INNFCExampleViewController.h"
#import 

API_AVAILABLE(ios(11.0))
@interface INNFCExampleViewController ()

@property (nonatomic, strong) NFCNDEFReaderSession *session;

@property (nonatomic, strong) NFCTagReaderSession *tagSession;
 
@property (nonatomic, strong) id currentTag;

@property (nonatomic, strong) UILabel *showLabel;

@end

@implementation INNFCExampleViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    self.view.backgroundColor = [UIColor whiteColor];
    
    UIButton *startQueryBtn;
    startQueryBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    startQueryBtn.frame = CGRectMake(50, 100, 60, 36);
    startQueryBtn.layer.cornerRadius = 4;
    startQueryBtn.backgroundColor = [UIColor brownColor];
    [startQueryBtn setTitle:@"开始识别" forState:UIControlStateNormal];
    [startQueryBtn addTarget:self action:@selector(startQueryBtnClick) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:startQueryBtn];
    
    UIButton *endQueryBtn;
    endQueryBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    endQueryBtn.frame = CGRectMake(250, 100, 60, 36);
    endQueryBtn.layer.cornerRadius = 4;
    endQueryBtn.backgroundColor = [UIColor brownColor];
    [endQueryBtn setTitle:@"结束识别" forState:UIControlStateNormal];
    [endQueryBtn addTarget:self action:@selector(endQueryBtnClick) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:endQueryBtn];
}

- (void)startQueryBtnClick {
    
    if (@available(iOS 13.0, *)) {
        if (NFCNDEFReaderSession.readingAvailable) {
            self.tagSession = [[NFCTagReaderSession alloc]
                                initWithPollingOption:(NFCPollingISO14443 | NFCPollingISO15693 | NFCPollingISO15693) delegate:self queue:dispatch_get_main_queue()];
            self.tagSession.alertMessage = @"读取卡片，请将卡片靠近手机";
            [self.tagSession beginSession]; //开始识别 弹出识别提示框
        }else{
            NSLog(@"NFC功能只支持iphone7以及iOS13.0以上设备");
        }
    }else{
        NSLog(@"NFC功能只支持iphone7以及iOS13.0以上设备");
    }
    
    /**
     //如果希望读取多个标签invalidateAfterFirstRead设置为NO
     if (@available(iOS 11.0, *)) {
         __weak typeof(self) weakSelf = self;
         self.session = [[NFCNDEFReaderSession alloc] initWithDelegate:weakSelf queue:dispatch_queue_create(NULL, DISPATCH_QUEUE_CONCURRENT) invalidateAfterFirstRead:YES];
         [self.session beginSession];
     } else {
         // Fallback on earlier versions
     }
     */
}

- (void)endQueryBtnClick {
    
    /**
     if (@available(iOS 11.0, *)) {
         [self.session invalidateSession];
     } else {
         // Fallback on earlier versions
     }
     */
}

#pragma mark -- 

//扫描到的回调

-(void)readerSession:(NFCNDEFReaderSession *)session didDetectNDEFs:(NSArray *)messages API_AVAILABLE(ios(11.0)){

    for (NFCNDEFMessage *message in messages) {
        for (NFCNDEFPayload *payload in message.records) {
            NSLog(@"readerSession payload data = %@", payload.payload);
            NSString *str = [[NSString alloc] initWithData:payload.payload encoding:NSUTF8StringEncoding];
            //回到主线程
            dispatch_async(dispatch_get_main_queue(), ^{
                NSLog(@"readerSession str:%@",str);
            });
        }
    }
}

//错误回调


-(void)readerSession:(NFCNDEFReaderSession *)session didInvalidateWithError:(NSError *)error API_AVAILABLE(ios(11.0)){
    NSLog(@"readerSession didInvalidateWithError error:%@", error);
}


#pragma mark -- NFCTagReaderSessionDelegate

/*!
 * @method tagReaderSession:didInvalidateWithError:
 *
 * @param session   The session object that is invalidated.
 * @param error     The error indicates the invalidation reason.
 *
 * @discussion      Gets called when a session becomes invalid.  At this point the client is expected to discard
 *                  the returned session object.
 */
- (void)tagReaderSession:(NFCTagReaderSession *)session didInvalidateWithError:(NSError *)error API_AVAILABLE(ios(13.0)) API_UNAVAILABLE(watchos, macos, tvos) {
    NSLog(@"tagReaderSession didInvalidateWithError error:%@", error);
    if (error.code == 200) {
        return;
    }
    [session invalidateSession];
}

/*!
 * @method tagReaderSessionDidBecomeActive:
 *
 * @param session   The session object in the active state.
 *
 * @discussion      Gets called when the NFC reader session has become active. RF is enabled and reader is scanning for tags.
 *                  The @link readerSession:didDetectTags: @link/ will be called when a tag is detected.
 */
- (void)tagReaderSessionDidBecomeActive:(NFCTagReaderSession *)session API_AVAILABLE(ios(13.0)) API_UNAVAILABLE(watchos, macos, tvos) {
    NSLog(@"tagReaderSession tagReaderSessionDidBecomeActive");
}

/*!
 * @method tagReaderSession:didDetectTags:
 *
 * @param session   The session object used for tag detection.
 * @param tags      Array of @link NFCTag @link/ objects.
 *
 * @discussion      Gets called when the reader detects NFC tag(s) in the polling sequence.
 */
- (void)tagReaderSession:(NFCTagReaderSession *)session didDetectTags:(NSArray<__kindof id> *)tags API_AVAILABLE(ios(13.0)) API_UNAVAILABLE(watchos, macos, tvos) {
    _currentTag = [tags firstObject];
    NSData *data ;
    if (self.currentTag.type == NFCTagTypeMiFare) {
        id mifareTag = [self.currentTag asNFCMiFareTag];
        data = mifareTag.identifier;
    }else if (self.currentTag.type == NFCTagTypeISO15693){
        id mifareTag = [self.currentTag asNFCISO15693Tag];
        data = mifareTag.identifier;
    }else if (self.currentTag.type == NFCTagTypeISO15693){
        id mifareTag = [self.currentTag asNFCISO15693Tag];
        data = mifareTag.identifier;
    }else{
        NSLog(@"未识别出NFC格式");
    }
        
    NSString *str = [self convertDataBytesToHex:data];
    NSLog(@"tagReaderSession didDetectTags str:%@", str);
    
    //识别成功处理
    [session invalidateSession];
}
     
     
     
- (NSString *)convertDataBytesToHex:(NSData *)dataBytes {
    if (!dataBytes || [dataBytes length] == 0) {
        return @"";
    }
    NSMutableString *hexStr = [[NSMutableString alloc] initWithCapacity:[dataBytes length]];
    [dataBytes enumerateByteRangesUsingBlock:^(const void *bytes, NSRange byteRange, BOOL *stop) {
        unsigned char *dataBytes = (unsigned char *)bytes;
        for (NSInteger i = 0; i < byteRange.length; i ++) {
            NSString *singleHexStr = [NSString stringWithFormat:@"%x", (dataBytes[i]) & 0xff];
            if ([singleHexStr length] == 2) {
                [hexStr appendString:singleHexStr];
            } else {
                [hexStr appendFormat:@"0%@", singleHexStr];
            }
        }
    }];
    return hexStr;
}



@end

至此，NFC标签Tag读取功能代码完成。

三、小结

iOS开发-CoreNFC实现NFC标签Tag读取功能

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