iOS-仿微信扫一扫、长按识别二维码，以及一句话生成二维码

1、二维码简介
在iOS中二维码的实质是一个字符串，一般用于制作名片，手机电商购物链家、微信扫一扫，微信支付，QQ加好友，以及移动支付等。其中用的最广的当然是大家熟知的支付宝，微信和QQ了。既然二维码用途这么广，很多APP里面都或多或少有二维码的存在，那么下面就扫一扫二维码，长按识别二维码，以及生成二维码从无到有的过程，和遇到的坑分享给大家。

2、进入主题
在一定的程度之后，相信大家都有封装的思想，那么本文有几个分装介绍给大家：
JWDQRCodeViewController.h 扫一扫控制器分装
JWDPreView.h 扫一扫动画界面封装
JWDCreatQRCodeView.h 生成二维码封装
下面就这三个类进行介绍

3、JWDQRCodeViewController 扫一扫控制器分装

JWDQRCodeViewController.h
.h 没什么可说的，给外界的接口

#import <UIKit/UIKit.h>

@interface JWDQRCodeViewController : UIViewController
- (instancetype)initWithFrame:(CGRect)frame;
@end

JWDQRCodeViewController.m
导入相应的头文件，必须的变量
其中SafariServices/SafariServices.h框架用于url跳转控制器，是iOS9之后的新特性，可以方便打开相应的网页界面。

#import "JWDQRCodeViewController.h"
#import <AVFoundation/AVFoundation.h>
#import "JWDPreView.h"
#import <SafariServices/SafariServices.h>

@interface JWDQRCodeViewController ()<AVCaptureMetadataOutputObjectsDelegate>
@property(nonatomic, strong)AVCaptureDeviceInput        *deviceInput;//!< 摄像头输入
@property(nonatomic, strong)AVCaptureMetadataOutput     *metadataOutput;//!< 输出
@property(nonatomic, strong)AVCaptureSession            *session;//!< 会话
@property(nonatomic, strong)AVCaptureVideoPreviewLayer  *previewLayer;//!< 预览
@property(nonatomic, strong)JWDPreView                  *preView;//!< <#value#>

@end

@implementation JWDQRCodeViewController

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super init];
    if (self) {
        self.view.frame = frame;
        [self initUiConfig];
    }
    return self;
}

-(void)initUiConfig {

    // 默认为后置摄像头
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    self.deviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:device error:NULL];
    // 解析输入的数据
    self.metadataOutput = [[AVCaptureMetadataOutput alloc] init];
    [self.metadataOutput setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    // 会话
    self.session = [[AVCaptureSession alloc] init];
    if ([self.session canAddInput:self.deviceInput]){
        [self.session addInput:self.deviceInput];
    }
    if([self.session canAddOutput:self.metadataOutput]){
        [self.session addOutput:self.metadataOutput];
    }
    // 设置数据采集质量
    self.session.sessionPreset = AVCaptureSessionPresetHigh;
    // 设置需要解析的数据类型，二维码
    self.metadataOutput.metadataObjectTypes = @[AVMetadataObjectTypeQRCode];
    JWDPreView *preView = [[JWDPreView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];
    self.preView = preView;
    [self.view addSubview:preView];
    preView.session = self.session;
    preView.backPreView = ^(JWDPreView *backPreView){
        [self.session stopRunning];
        [self dismissViewControllerAnimated:YES completion:nil];
        // 销毁定时器
        if (backPreView.timer){
            [backPreView.timer invalidate];
            backPreView.timer = nil;
        }
    };
    [self.session startRunning];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    
}

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection {
    
    for (AVMetadataMachineReadableCodeObject *obj in metadataObjects) {
        SFSafariViewController *safariVC = [[SFSafariViewController alloc] initWithURL:[NSURL URLWithString:obj.stringValue]];
        [self presentViewController:safariVC animated:YES completion:nil];
    }
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

上面建立采集二维码的过滤器，和基本的输入和输出的建立，链接输入和输出的会话建立，以及开启和适当的时候关闭会话的处理。

切记这里要使用摄像头，所以要者info.plist 里面设置访问权限

Paste_Image.png

在解析获取捕捉到的信息后会在代理 AVCaptureMetadataOutputObjectsDelegate的下面方法里面获取信息

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection {
    
    for (AVMetadataMachineReadableCodeObject *obj in metadataObjects) {
        SFSafariViewController *safariVC = [[SFSafariViewController alloc] initWithURL:[NSURL URLWithString:obj.stringValue]];
        [self presentViewController:safariVC animated:YES completion:nil];
    }
}

获取到相应的数据后可以在这里面做一些业务逻辑，本人在这里就用到SFSafariViewController控制器来代开网页

好了下面介绍扫描界面
4.JWDPreView 扫一扫动画界面封装

JWDPreView.h

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
@class JWDPreView;

typedef void(^backPreView) (JWDPreView *preView);

@interface JWDPreView : UIView

- (instancetype)initWithFrame:(CGRect)frame;

@property(nonatomic, strong)AVCaptureSession    *session;//!< 渲染会话层
@property (nonatomic, copy) backPreView         backPreView;//!< 返回按钮回调
@property(nonatomic, strong)NSTimer             *timer;//!< <#value#>

@end

JWDPreView.m

#import "JWDPreView.h"

@interface JWDPreView ()
{
    UIImageView   *_imageView;
    UIImageView   *_lineImageView;
    UIButton      *_backBtn;
}

@end

@implementation JWDPreView

// 修改当前View 的图层类别
+(Class)layerClass {

    return [AVCaptureVideoPreviewLayer class];
}

-(void)setSession:(AVCaptureSession *)session {

    _session = session;
    AVCaptureVideoPreviewLayer *layer = (AVCaptureVideoPreviewLayer *)self.layer;
    layer.session = session;
}

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self initUiConfig];
    }
    return self;
}
- (void)initUiConfig {
    
    _backBtn = [[UIButton alloc] initWithFrame:CGRectMake(30, 50, 40, 20)];
    [_backBtn setTitle:@"返回" forState:UIControlStateNormal];
    [_backBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [_backBtn addTarget:self action:@selector(backButtonDid) forControlEvents:UIControlEventTouchUpInside];
    [self addSubview:_backBtn];
    
    _imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"pick_bg.png"]];
    _imageView.frame = CGRectMake(self.bounds.size.width * 0.5 - 140, self.bounds.size.height * 0.5 - 140, 280, 280);
    [self addSubview:_imageView];
    
    _lineImageView = [[UIImageView alloc] initWithFrame:CGRectMake(30, 10, 220, 2)];
    _lineImageView.image = [UIImage imageNamed:@"line.png"];
    [_imageView addSubview:_lineImageView];
    
    _timer = [NSTimer scheduledTimerWithTimeInterval:3 target:self selector:@selector(animation) userInfo:nil repeats:YES];
}
- (void)animation
{
    [UIView animateWithDuration:2.8 delay:0 options:UIViewAnimationOptionCurveLinear animations:^{
        
        _lineImageView.frame = CGRectMake(30, 260, 220, 2);
        
    } completion:^(BOOL finished) {
        _lineImageView.frame = CGRectMake(30, 10, 220, 2);
    }];
}

- (void)backButtonDid {

    if (self.backPreView){
        self.backPreView(self);
    }
}

@end

在.m中一个重点就是 扫一扫界面浏览layer的修改

Paste_Image.png

在UIView中默认的 为 [CALayer class]而这不是二维码扫描所需的layer，所以修改。这样强转后的layer才有session的会话设置

// 修改当前View 的图层类别
+(Class)layerClass {

   return [AVCaptureVideoPreviewLayer class];
}

-(void)setSession:(AVCaptureSession *)session {

   _session = session;
   AVCaptureVideoPreviewLayer *layer = (AVCaptureVideoPreviewLayer *)self.layer;
   layer.session = session;
}

5.JWDCreatQRCodeView 生成二维码封装

JWDCreatQRCodeView.h

一句话生成二维码的接口

#import <UIKit/UIKit.h>

@interface JWDQRCodeViewController : UIViewController
- (instancetype)initWithFrame:(CGRect)frame;
@end

JWDCreatQRCodeView.m

#import "JWDQRCodeViewController.h"
#import <AVFoundation/AVFoundation.h>
#import "JWDPreView.h"
#import <SafariServices/SafariServices.h>

@interface JWDQRCodeViewController ()<AVCaptureMetadataOutputObjectsDelegate>
@property(nonatomic, strong)AVCaptureDeviceInput        *deviceInput;//!< 摄像头输入
@property(nonatomic, strong)AVCaptureMetadataOutput     *metadataOutput;//!< 输出
@property(nonatomic, strong)AVCaptureSession            *session;//!< 会话
@property(nonatomic, strong)AVCaptureVideoPreviewLayer  *previewLayer;//!< 预览
@property(nonatomic, strong)JWDPreView                  *preView;//!< <#value#>

@end

@implementation JWDQRCodeViewController

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super init];
    if (self) {
        self.view.frame = frame;
        [self initUiConfig];
    }
    return self;
}

-(void)initUiConfig {

    // 默认为后置摄像头
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    self.deviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:device error:NULL];
    // 解析输入的数据
    self.metadataOutput = [[AVCaptureMetadataOutput alloc] init];
    [self.metadataOutput setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    // 会话
    self.session = [[AVCaptureSession alloc] init];
    if ([self.session canAddInput:self.deviceInput]){
        [self.session addInput:self.deviceInput];
    }
    if([self.session canAddOutput:self.metadataOutput]){
        [self.session addOutput:self.metadataOutput];
    }
    // 设置数据采集质量
    self.session.sessionPreset = AVCaptureSessionPresetHigh;
    // 设置需要解析的数据类型，二维码
    self.metadataOutput.metadataObjectTypes = @[AVMetadataObjectTypeQRCode];
    JWDPreView *preView = [[JWDPreView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];
    self.preView = preView;
    [self.view addSubview:preView];
    preView.session = self.session;
    preView.backPreView = ^(JWDPreView *backPreView){
        [self.session stopRunning];
        [self dismissViewControllerAnimated:YES completion:nil];
        // 销毁定时器
        if (backPreView.timer){
            [backPreView.timer invalidate];
            backPreView.timer = nil;
        }
    };
    [self.session startRunning];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    
}

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection {
    
    for (AVMetadataMachineReadableCodeObject *obj in metadataObjects) {
        SFSafariViewController *safariVC = [[SFSafariViewController alloc] initWithURL:[NSURL URLWithString:obj.stringValue]];
        [self presentViewController:safariVC animated:YES completion:nil];
    }
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

Paste_Image.png

Paste_Image.png

好了，这样介绍完了，上面的几个类就可以实现功能。

6.下面介绍
ViewController继承基本的全部功能

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
#import "JWDPreView.h"
#import <SafariServices/SafariServices.h>
#import "JWDQRCodeViewController.h"
#import "JWDCreatQRCodeView.h"

@interface ViewController ()

@property(nonatomic, strong)UIButton              *code;//!< <#value#>
@property(nonatomic, strong)UIButton              *code1;//!< <#value#>
@property(nonatomic, strong)JWDCreatQRCodeView    *creatQRCodeView;//!< <#value#>

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    CGFloat X = (self.view.frame.size.width - 2*100)/3.0;
    
    _code = [[UIButton alloc] initWithFrame:CGRectMake(X, 100, 100, 60)];
    _code.backgroundColor = [UIColor yellowColor];
    [_code setTitle:@"扫一扫" forState:UIControlStateNormal];
    [_code setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [_code addTarget:self action:@selector(codeDidClick) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_code];
    
    
    _code1 = [[UIButton alloc] initWithFrame:CGRectMake(2*X + 100, 100, 100, 60)];
    _code1.backgroundColor = [UIColor yellowColor];
    [_code1 setTitle:@"生成二维码" forState:UIControlStateNormal];
    [_code1 setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [_code1 addTarget:self action:@selector(code1DidClick) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_code1];
    
}
- (void)codeDidClick {
    
    JWDQRCodeViewController *QRCodeVC = [[JWDQRCodeViewController alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
    [self presentViewController:QRCodeVC animated:YES completion:nil];

}

- (void)code1DidClick {

    UIView *qrCodeView = [[UIView alloc] initWithFrame:CGRectMake((self.view.frame.size.width-200)*0.5, 250, 200, 220)];
    [self.view addSubview:qrCodeView];
    
    JWDCreatQRCodeView *creatQRCodeView = [[JWDCreatQRCodeView alloc] initWithFrame:CGRectMake(0, 0, 200, 200) withQRCodeString:@"//www.greatytc.com/users/5b9953c3d3ad/latest_articles" withQRCodeCenterImage:@"me"];
    self.creatQRCodeView = creatQRCodeView;
    
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 200, 200, 20)];
    label.text = @"长按识别二维码，跳转网页";
    label.font = [UIFont systemFontOfSize:12];
    label.textAlignment = NSTextAlignmentCenter;
    [qrCodeView addSubview:label];
    
    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressDid)];
    creatQRCodeView.userInteractionEnabled = YES;
    [creatQRCodeView addGestureRecognizer:longPress];
    
    [qrCodeView addSubview:creatQRCodeView];
    
}

- (void)longPressDid{
    
    // 0.创建上下文
    CIContext *context = [[CIContext alloc] init];
    
    // 1.创建一个探测器
    CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:context options:@{CIDetectorAccuracy: CIDetectorAccuracyLow}];
    
    // 2.直接开始识别图片,获取图片特征
    CIImage *imageCI = [[CIImage alloc] initWithImage:self.creatQRCodeView.image];
    NSArray<CIFeature *> *features = [detector featuresInImage:imageCI];
    CIQRCodeFeature *codef = (CIQRCodeFeature *)features.firstObject;
    
    // 弹框
    UIAlertController *alertC = [UIAlertController alertControllerWithTitle:@"识别图中二维码" message:nil preferredStyle:UIAlertControllerStyleAlert];
    [alertC addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
        NSLog(@"取消");
    }]];
    __weak ViewController *weakSelf = self;
    [alertC addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        SFSafariViewController *safariVC = [[SFSafariViewController alloc] initWithURL:[NSURL URLWithString:codef.messageString]];
        [weakSelf presentViewController:safariVC animated:YES completion:nil];
    }]];
    [self presentViewController:alertC animated:YES completion:nil];
    
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

完结，小小的一个demo，可能还有不完善的地方，当你发现了还请不吝赐教，谢谢。
最后奉上demo 地址 https://github.com/weidongjiang/JWD-QRCode

如果对你有用，解决了你的问题，得到了帮助，还请star。相互学习。