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<NFCNDEFMessage *> *)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 <CoreNFC/CoreNFC.h>
API_AVAILABLE(ios(11.0))
@interface INNFCExampleViewController ()<NFCNDEFReaderSessionDelegate, NFCTagReaderSessionDelegate>
@property (nonatomic, strong) NFCNDEFReaderSession *session;
@property (nonatomic, strong) NFCTagReaderSession *tagSession;
@property (nonatomic, strong) id<NFCMiFareTag> 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 -- <NFCNDEFReaderSessionDelegate>
//扫描到的回调
-(void)readerSession:(NFCNDEFReaderSession *)session didDetectNDEFs:(NSArray<NFCNDEFMessage *> *)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<NFCTag>> *)tags API_AVAILABLE(ios(13.0)) API_UNAVAILABLE(watchos, macos, tvos) {
_currentTag = [tags firstObject];
NSData *data ;
if (self.currentTag.type == NFCTagTypeMiFare) {
id<NFCMiFareTag> mifareTag = [self.currentTag asNFCMiFareTag];
data = mifareTag.identifier;
}else if (self.currentTag.type == NFCTagTypeISO15693){
id<NFCISO15693Tag> mifareTag = [self.currentTag asNFCISO15693Tag];
data = mifareTag.identifier;
}else if (self.currentTag.type == NFCTagTypeISO15693){
id<NFCISO15693Tag> 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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