iOS 二维码 学习

这段时间忙着交接工作,找工作,找房子,入职,杂七杂八的,差不多一个月没有静下来学习了.这周末晚上等外卖的时间学习一下二维码的制作与扫描.

项目采用OC语言,只要使用iOS自带的CoreImage框架,通过滤镜CIFilter生成二维码,扫描使用原生自带相机实现.

开撸:

先写一个类,封装把string转换我image和把CIImage转换为string:

QRImage.h

//
//  QRImage.h
//  QRcode
//
//  Created by Shaoting Zhou on 2017/11/19.
//  Copyright © 2017年 Shaoting Zhou. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <CoreImage/CoreImage.h>
#import <UIKit/UIKit.h>

@interface QRImage : NSObject

+ (UIImage *)imageWithQRString:(NSString *)string;  //把string转换我image
+ (NSString *)stringFromCiImage:(CIImage *)ciimage; //把CIImage转换为string

@end

QRImage.m

//
//  QRImage.m
//  QRcode
//
//  Created by Shaoting Zhou on 2017/11/19.
//  Copyright © 2017年 Shaoting Zhou. All rights reserved.
//

#import "QRImage.h"

@implementation QRImage

#pragma mark - 把string转换为Image
+ (UIImage *)imageWithQRString:(NSString *)string{
    NSData * stringData = [string dataUsingEncoding:NSUTF8StringEncoding];
    
    CIFilter * qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"]; //过滤器
    [qrFilter setValue:stringData forKey:@"inputMessage"];
    [qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];  //纠错等级
    UIImage * image =  [self createUIImageFromCIImage:qrFilter.outputImage withSize:300];
    return image;
}


#pragma mark - CIImgae ->  UIImage
+ (UIImage *)createUIImageFromCIImage:(CIImage *)image withSize:(CGFloat)size{
    CGRect extent = CGRectIntegral(image.extent);
    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
    
    //1.创建bitmap;
    size_t width = CGRectGetWidth(extent) * scale;
    size_t height = CGRectGetHeight(extent) * scale;
    CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
    CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
    CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
    CGContextScaleCTM(bitmapRef, scale, scale);
    CGContextDrawImage(bitmapRef, extent, bitmapImage);
    
    //2.保存bitmap到图片
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    return [UIImage imageWithCGImage:scaledImage];
    
}


#pragma mark - 把image转换为string
+ (NSString *)stringFromCiImage:(CIImage *)ciimage{
    NSString * content = nil;
    if(!ciimage){
        return  content;
    }
    CIDetector * detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:[CIContext contextWithOptions:nil] options:@{CIDetectorAccuracy:CIDetectorAccuracyHigh}];
    NSArray * features = [detector featuresInImage:ciimage];
    if(features.count){
        for (CIFeature * feature in features) {
            if([feature isKindOfClass:[CIQRCodeFeature class]]){
                content = ((CIQRCodeFeature *)feature).messageString;
                break;
            }
        }
    }else{
        NSLog(@"解析失败,确保硬件支持");
    }
        
    return content;
}
@end

上面的代码就是关键之处.

下面,写一个界面生成二维码,通过上面写好的string转换我image,显示在屏幕之上.

      MainViewController.h

//
//  MainViewController.h
//  QRcode
//
//  Created by Shaoting Zhou on 2017/11/18.
//  Copyright © 2017年 Shaoting Zhou. All rights reserved.
//

#import <UIKit/UIKit.h>
#import "QRImage.h"
#import "ScanViewController.h"

@interface MainViewController : UIViewController
@property (nonatomic,strong) UIImageView * qrImageView;
@property (nonatomic,strong) UITextField * textField;
@end

    MainViewController.m

//
//  MainViewController.m
//  QRcode
//
//  Created by Shaoting Zhou on 2017/11/18.
//  Copyright © 2017年 Shaoting Zhou. All rights reserved.
//

#import "MainViewController.h"

@interface MainViewController ()

@end

@implementation MainViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self setUI];
    self.title = @"生成二维码";
    
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"扫描" style:(UIBarButtonItemStylePlain) target:self action:@selector(scangQRimage)];
}

-(void)setUI{
    self.textField = [[UITextField alloc]initWithFrame:CGRectMake(10, 200, 200, 50)];
    self.textField.borderStyle = UITextBorderStyleRoundedRect;
    [self.view addSubview:self.textField];
    
    UIButton * btn = [[UIButton alloc]initWithFrame:CGRectMake(230, 200, 120, 50)];
    [btn setTitle:@"生成二维码" forState:(UIControlStateNormal)];
    [btn setTitleColor:[UIColor redColor] forState:(UIControlStateNormal)];
    [btn addTarget:self action:@selector(makeQRcode) forControlEvents:(UIControlEventTouchUpInside)];
    [self.view addSubview:btn];
    
    self.qrImageView = [[UIImageView alloc]initWithFrame:CGRectMake(20, 300, 200, 200)];
    [self.view addSubview:self.qrImageView];
    
    
}
#pragma mark - 生成二维码
-(void)makeQRcode{
    [self.textField resignFirstResponder];
    UIImage * img = [QRImage imageWithQRString:self.textField.text];
    self.qrImageView.image = img;
}

#pragma mark - push到扫描界面
-(void)scangQRimage{
    ScanViewController * scanVC = [[ScanViewController alloc]init];
    [self.navigationController pushViewController:scanVC animated:NO];
}

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

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end

再写一个界面扫描二维码和通过相册选择二维码扫描,通过上面写好的把CIImage转换为string,扫描出二维码信息显示出来即可.

ScanViewController.h

//
//  ScanViewController.h
//  QRcode
//
//  Created by Shaoting Zhou on 2017/11/19.
//  Copyright © 2017年 Shaoting Zhou. All rights reserved.
//

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#import "QRImage.h"
@interface ScanViewController : UIViewController <AVCaptureMetadataOutputObjectsDelegate,UINavigationControllerDelegate,UIImagePickerControllerDelegate>
@property (nonatomic,strong) AVCaptureSession * session;
@property (nonatomic,strong) UITextField * textField;

@end

ScanViewController.m

//
//  ScanViewController.m
//  QRcode
//
//  Created by Shaoting Zhou on 2017/11/19.
//  Copyright © 2017年 Shaoting Zhou. All rights reserved.
//

#import "ScanViewController.h"

@interface ScanViewController ()

@end

@implementation ScanViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.title = @"扫描二维码";
    
    self.textField = [[UITextField alloc]initWithFrame:CGRectMake(10, 100, 200, 50)];
    self.textField.borderStyle = UITextBorderStyleRoundedRect;
    self.textField.userInteractionEnabled = NO;
    [self.view addSubview:self.textField];
    
    
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"相册" style:(UIBarButtonItemStylePlain) target:self action:@selector(presentImagePicker)];
    
    
}
- (void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    [self startScan];
    
}

#pragma  mark - 开始扫描
- (void)startScan{
    if([AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo] == AVAuthorizationStatusAuthorized || [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo] == AVAuthorizationStatusNotDetermined ){
        self.session = [[AVCaptureSession alloc]init];
        AVCaptureDeviceInput * input = [[AVCaptureDeviceInput alloc]initWithDevice:[AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo] error:nil];
        if(input){
            [self.session addInput:input];
        }
        
        AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutput alloc]init];
        [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
        if(output){
            [self.session addOutput:output];
        }
        
        NSMutableArray * ary = [[NSMutableArray alloc]init];
        if([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeQRCode]){
            [ary addObject:AVMetadataObjectTypeQRCode];
        }
        if([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeEAN13Code]){
            [ary addObject:AVMetadataObjectTypeEAN13Code];
        }
        if([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeEAN8Code]){
            [ary addObject:AVMetadataObjectTypeEAN8Code];
        }
        if([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeCode128Code]){
            [ary addObject:AVMetadataObjectTypeCode128Code];
        }
        output.metadataObjectTypes = ary;
        
        AVCaptureVideoPreviewLayer * layer = [AVCaptureVideoPreviewLayer layerWithSession:self.session];
        layer.videoGravity = AVLayerVideoGravityResizeAspectFill;
        layer.frame = CGRectMake((self.view.bounds.size.width - 300)/2, 164, 300, 300);
        [self.view.layer addSublayer:layer];
        
        UIImageView * imageView = [[UIImageView alloc]initWithFrame:CGRectMake((self.view.bounds.size.width - 300)/2, 164, 300, 300)];
        
        [self.view addSubview:imageView];
        [self.session startRunning];
    }
}

#pragma mark - AVCaptureMetadataOutputObjectsDelegate代理方法
- (void)captureOutput:(AVCaptureOutput *)output didOutputMetadataObjects:(NSArray<__kindof AVMetadataObject *> *)metadataObjects fromConnection:(AVCaptureConnection *)connection{
    NSString * str = nil;
    for (AVMetadataObject * obj in metadataObjects) {
        if([obj.type isEqualToString:AVMetadataObjectTypeQRCode]){
            str = [(AVMetadataMachineReadableCodeObject *)obj stringValue];
            [self.session startRunning];
            break;
        }
    }
    self.textField.text = str;
}

#pragma mark - UIImagePickerControllerDelegate代理方法
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
    UIImage * image = [info objectForKey:UIImagePickerControllerOriginalImage];
    
    CIImage * ciimage = [[CIImage alloc]initWithImage:image];
    NSString * str = [QRImage stringFromCiImage:ciimage];
    self.textField.text = str;
    [self dismissViewControllerAnimated:YES completion:nil];
}


#pragma mark - 弹出相册
- (void)presentImagePicker{
    UIImagePickerController * imagePicker = [[UIImagePickerController alloc]init];
    imagePicker.delegate = self;
    [self presentViewController:imagePicker animated:NO completion:nil];
}

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

/*
 #pragma mark - Navigation
 
 // In a storyboard-based application, you will often want to do a little preparation before navigation
 - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
 // Get the new view controller using [segue destinationViewController].
 // Pass the selected object to the new view controller.
 }
 */

@end

github: https://github.com/pheromone/QRcode

效果如下: