IOS-二维码

一、二维码的生成

从iOS7开始集成了二维码的生成和读取功能

此前被广泛使用的zbarsdk目前不支持64位处理器

 

生成二维码的步骤：

1.导入CoreImage框架

2.通过滤镜CIFilter生成二维码

 

二维码的内容(传统的条形码只能放数字)：

纯文本

名片

URL

 

生成二维码

// 1. 实例化二维码滤镜

CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

// 2. 恢复滤镜的默认属性

[filter setDefaults];

// 3. 将字符串转换成NSData

NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];

// 4. 通过KVO设置滤镜inputMessage数据

[filter setValue:data forKey:@"inputMessage"];

// 5. 获得滤镜输出的图像

CIImage *outputImage = [filter outputImage];

// 6. 将CIImage转换成UIImage，并放大显示

return [UIImage imageWithCIImage:outputImage scale:20.0 orientation:UIImageOrientationUp];

二、读取二维码

读取二维码需要导入AVFoundation框架

利用摄像头识别二维码中的内容（模拟器不行）

 

1.输入（摄像头）

2.由会话将摄像头采集到的二维码图像转换成字符串数据

3.输出（数据）

4.由预览图层显示扫描场景

 

设置拍摄会话

// 1. 实例化拍摄设备

AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

// 2. 设置输入设备

AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];

// 3. 设置元数据输出

// 3.1 实例化拍摄元数据输出

AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];

// 3.3 设置输出数据代理

[output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];

// 4. 添加拍摄会话

// 4.1 实例化拍摄会话

AVCaptureSession *session = [[AVCaptureSession alloc] init];

// 4.2 添加会话输入

[session addInput:input];

// 4.3 添加会话输出

[session addOutput:output];

// 4.3 设置输出数据类型，需要将元数据输出添加到会话后，才能指定元数据类型，否则会报错

[output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];

设置拍摄视频预览图层

// 5. 视频预览图层

// 5.1 实例化预览图层

AVCaptureVideoPreviewLayer *preview = [AVCaptureVideoPreviewLayer layerWithSession:_session];

preview.videoGravity = AVLayerVideoGravityResizeAspectFill;

preview.frame = self.view.bounds;

// 5.2 将图层插入当前视图

[self.view.layer insertSublayer:preview atIndex:100];

self.previewLayer = preview;

// 6. 启动会话

[_session startRunning];

代码：

//
//  ViewController.m
//  01-生成二维码
//
//  Created by apple on 15/8/18.
//  Copyright (c) 2015年 xiaomage. All rights reserved.
//

#import "ViewController.h"
#import <CoreImage/CoreImage.h>

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UIImageView *imageView;

@end

@implementation ViewController

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

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    // 1.创建滤镜对象
    CIFilter *fiter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    
    // 2.设置相关属性
    [fiter setDefaults];
    
    // 3.设置输入数据
    NSString *inputData = @"http://www.520it.com";
    NSData *data = [inputData dataUsingEncoding:NSUTF8StringEncoding];
    [fiter setValue:data forKeyPath:@"inputMessage"];
    
    // 4.获取输出结果
    CIImage *outputImage = [fiter outputImage];
    
    // 5.显示二维码
    self.imageView.image = [self createNonInterpolatedUIImageFormCIImage:outputImage withSize:200];
}

/**
 *  根据CIImage生成指定大小的UIImage
 *
 *  @param image CIImage
 *  @param size  图片宽度
 */
- (UIImage *)createNonInterpolatedUIImageFormCIImage:(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];
}

@end

//
//  ViewController.m
//  02-扫描二维码
//
//  Created by apple on 15/8/18.
//  Copyright (c) 2015年 xiaomage. All rights reserved.
//

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>

@interface ViewController () <AVCaptureMetadataOutputObjectsDelegate>

@end

@implementation ViewController

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

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    // 1.创建捕捉会话
    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    
    // 2.设置输入设备
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    AVCaptureDeviceInput *inputDevice = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    [session addInput:inputDevice];
    
    // 3.设置输入方式
    AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    [session addOutput:output];
    [output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];
    
    // 4.添加一个显示的layer
    AVCaptureVideoPreviewLayer *layer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
    layer.frame = self.view.bounds;
    [self.view.layer addSublayer:layer];
    
    // 5.开始扫描
    [session startRunning];
}

#pragma mark - 获取扫描结果
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
    if (metadataObjects.count > 0) {
        AVMetadataMachineReadableCodeObject *object = [metadataObjects lastObject];
        NSLog(@"%@", object.stringValue);
    }
}

@end