iOS上有办法生成二维码图像吗

Is there a standard way to generate a QR code and attach it to a mail item from iOS client app (no server code)?

是否有一种标准的方法来生成二维码并将其附加到iOS客户端应用程序的邮件条目上(没有服务器代码)?

9 个解决方案

#1

Since iOS 7, you can use a Core Image filter to generate QR images. See the final tip here:

自ios7以来，您可以使用核心图像过滤器来生成QR图像。请看最后的提示:

- (CIImage *)createQRForString:(NSString *)qrString {
    NSData *stringData = [qrString dataUsingEncoding: NSISOLatin1StringEncoding];

    CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    [qrFilter setValue:stringData forKey:@"inputMessage"];

    return qrFilter.outputImage;
}

#2

For Obj-C version that perfectly works for me, I've mixed answers पवन and Teja Kumar Bethina:

Obj-C版本,很适合我,我混合答案पवनTeja Kumar Bethina:

NSString *qrString = @"My string to encode";
NSData *stringData = [qrString dataUsingEncoding: NSUTF8StringEncoding];

CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
[qrFilter setValue:stringData forKey:@"inputMessage"];
[qrFilter setValue:@"H" forKey:@"inputCorrectionLevel"];

CIImage *qrImage = qrFilter.outputImage;
float scaleX = self.qrImageView.frame.size.width / qrImage.extent.size.width;
float scaleY = self.qrImageView.frame.size.height / qrImage.extent.size.height;

qrImage = [qrImage imageByApplyingTransform:CGAffineTransformMakeScale(scaleX, scaleY)];

self.qrImageView.image = [UIImage imageWithCIImage:qrImage
                                             scale:[UIScreen mainScreen].scale
                                       orientation:UIImageOrientationUp];

#3

Using Swift 2

使用快速2

import UIKit
import CoreImage

func createQRFromString(str: String) -> CIImage? {
    let stringData = str.dataUsingEncoding(NSUTF8StringEncoding)

    let filter = CIFilter(name: "CIQRCodeGenerator")

    filter?.setValue(stringData, forKey: "inputMessage")

    filter?.setValue("H", forKey: "inputCorrectionLevel")

    return filter?.outputImage
}

if let img = createQRFromString("Hello world program created by someone") {
    let somImage = UIImage(CIImage: img, scale: 1.0, orientation: UIImageOrientation.Down)
}

Swift 3.0

斯威夫特3.0

import UIKit
import CoreImage

func createQRFromString(_ str: String) -> CIImage? {
        let stringData = str.data(using: String.Encoding.utf8)

        let filter = CIFilter(name: "CIQRCodeGenerator")

        filter?.setValue(stringData, forKey: "inputMessage")

        filter?.setValue("H", forKey: "inputCorrectionLevel")

        if let img = createQRFromString("Hello world program created by someone") {
            let somImage = UIImage(ciImage: img, scale: 1.0, orientation: UIImageOrientation.down)
        }

        return filter?.outputImage
    }

if let img = createQRFromString("Hello world program created by someone") {
            let somImage = UIImage(ciImage: img, scale: 1.0, orientation: UIImageOrientation.down)
        }

#4

It has been a while since this question was asked and a number of almost perfect answers have been given already. However I had to tweak and combine several answers to get it working perfectly for AppleTV 4K, iPhone X and iPadPro using Xcode 9.2 in 2018. Here's the code if anyone needs it.

问这个问题已经有一段时间了，现在已经给出了一些近乎完美的答案。然而，我不得不调整和合并几个答案，以便在2018年使用Xcode 9.2的AppleTV 4K、iPhone X和iPadPro上完美运行。这是密码，如果有人需要的话。

@IBOutlet weak var qrCodeBox: UIImageView!

func createQRFromString(_ str: String, size: CGSize) -> UIImage {
    let stringData = str.data(using: .utf8)

  let qrFilter = CIFilter(name: "CIQRCodeGenerator")!
  qrFilter.setValue(stringData, forKey: "inputMessage")
  qrFilter.setValue("H", forKey: "inputCorrectionLevel")

  let minimalQRimage = qrFilter.outputImage!
  // NOTE that a QR code is always square, so minimalQRimage..width === .height
  let minimalSideLength = minimalQRimage.extent.width

  let smallestOutputExtent = (size.width < size.height) ? size.width : size.height
  let scaleFactor = smallestOutputExtent / minimalSideLength
  let scaledImage = minimalQRimage.transformed(
    by: CGAffineTransform(scaleX: scaleFactor, y: scaleFactor))

  return UIImage(ciImage: scaledImage, 
                 scale: UIScreen.main.scale, 
                 orientation: .up)
}

override func viewDidLoad() {
    super.viewDidLoad()
    let myQRimage = createQRFromString("https://www.apple.com", 
                      size: qrCodeBox.frame.size)
    qrCodeBox.image = myQRimage
}

#5

Code to generate QR image in Swift 2.0.

在Swift 2.0中生成QR图像的代码。

let reqStr = “string to convert as QR code”
let data = reqStr.dataUsingEncoding(NSISOLatin1StringEncoding, allowLossyConversion: false)

let filter = CIFilter(name: "CIQRCodeGenerator")
filter!.setValue(data, forKey: "inputMessage")

let qrImage:CIImage = filter!.outputImage!

//qrImageView is a IBOutlet of UIImageView        
let scaleX = qrImageView.frame.size.width / qrImage.extent.size.width
let scaleY = qrImageView.frame.size.height / qrImage.extent.size.height

let resultQrImage = qrImage.imageByApplyingTransform(CGAffineTransformMakeScale(scaleX, scaleY))
qrImageView.image = UIImage(CIImage: resultQrImage)

#6

I have used the QR Code Encoder for QR generation. It is very easy to use. There are some other option to generate, e.g this.

我使用了二维码编码器进行二维码生成。它很容易使用。还有其他生成选项，e。g。

#7

...which will let me generate links...

…这会让我生成链接……

First, you need to find a short link service, e.g. bit.ly or goo.by, to make a long link shorter and thus reduce QR Code size.

首先，您需要找到一个短链接服务，例如bit。ly或感伤。通过，使长链接更短，从而减少二维码的大小。

To perform this task automatically you will have to use some web service.

要自动执行此任务，您必须使用一些web服务。

...then generate a QR code...

…然后生成二维码……

ZXing is a popular open source QR Code generator also available for iOS

ZXing是一个流行的开源二维码生成器，iOS也可以使用它

#8

If you don't mind using public api, here is an easy 10 seconds method. http://goqr.me/api

如果您不介意使用公共api，这里有一个简单的10秒方法。http://goqr.me/api

Just fill in the data parameter, and load the image from the response. Cheers.

只需填充数据参数，并从响应加载图像。欢呼。

#9

I created a NSString Category for Obj-C, taking Mike Demidov awesome answer

我为object - c创建了一个NSString类别，选了Mike Demidov的超棒答案

NString+GGQRCode.h

NString + GGQRCode.h

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

@interface NSString (GGQRCode)

-(UIImage *)qrCodeImage:(CGFloat)width height:(CGFloat)height;
-(UIImage *)qrCodeImage:(CGFloat)width height:(CGFloat)height scale:(CGFloat)scale orientation:(UIImageOrientation)orientation;

@end

NString+GGQRCode.m

NString + GGQRCode.m

#import "NSString+GGQRCode.h"

@implementation NSString (GGQRCode)

-(UIImage *)qrCodeImage:(CGFloat)width height:(CGFloat)height
{
    return [self qrCodeImage:width height:height scale:[UIScreen mainScreen].scale orientation:UIImageOrientationUp];
}

-(UIImage *)qrCodeImage:(CGFloat)width height:(CGFloat)height scale:(CGFloat)scale orientation:(UIImageOrientation)orientation
{
    NSData *stringData = [self dataUsingEncoding: NSUTF8StringEncoding];

    CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    [qrFilter setValue:stringData forKey:@"inputMessage"];
    [qrFilter setValue:@"H" forKey:@"inputCorrectionLevel"];

    CIImage *qrImage = qrFilter.outputImage;
    float scaleX = width / qrImage.extent.size.width;
    float scaleY = height / qrImage.extent.size.height;

    qrImage = [qrImage imageByApplyingTransform:CGAffineTransformMakeScale(scaleX, scaleY)];

    return [UIImage imageWithCIImage:qrImage scale:scale orientation:orientation];
}

@end