使用
AVFoundation框架识别解码二维码
参考
- GitHub 源码：shinobicontrols/iOS7-day-by-day
- 天天品尝iOS7甜点 :: Day 16 :: Decoding QR Codes with AVFoundation
- iOS-原生扫描登录 AVCaptureDevice、AVCaptureSession、AVCaptureInput、AVCaptureOutput、AVCaptureVideoPreviewLayer 介绍及示例
Drawing the code outline - 给二维码添加上线框
这个类用于实时绘制二维码边框
// *********************************************
// SCShapeView.h
#import
/**
给二维码添加线框
*/
@interface SCShapeView : UIView
// 封装了一系列点
@property (nonatomic, strong) NSArray *corners;
@end
// *********************************************
// SCShapeView.m
#import "SCShapeView.h"
@interface SCShapeView () {
CAShapeLayer *_outline; // 用于绘制线框的图层
}
@end
@implementation SCShapeView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
_outline = [CAShapeLayer new];
_outline.strokeColor = [[[UIColor greenColor] colorWithAlphaComponent:0.8] CGColor];
_outline.lineWidth = 2.0;
_outline.fillColor = [[UIColor clearColor] CGColor];
[self.layer addSublayer:_outline];
}
return self;
}
- (void)setCorners:(NSArray *)corners
{
if(corners != _corners) {
_corners = corners;
// 如果corners属性发生了变化，图形就将会使用新的位置进行绘制
_outline.path = [[self createPathFromPoints:corners] CGPath];
}
}
// 通过封装了CGPoint对象的数组对象来创建 UIBezierPath
- (UIBezierPath *)createPathFromPoints:(NSArray *)points
{
UIBezierPath *path = [UIBezierPath new];
// 起点
[path moveToPoint:[[points firstObject] CGPointValue]];
// 添加线
for (NSUInteger i = 1; i < [points count]; i++) {
[path addLineToPoint:[points[i] CGPointValue]];
}
// 返回到起点
[path addLineToPoint:[[points firstObject] CGPointValue]];
return path;
}
@end
捕获并显示二维码
// *********************************************
// SCViewController.h
#import
@interface SCViewController : UIViewController
@end
// *********************************************
// SCViewController.m
#import "SCViewController.h"
@import AVFoundation;
#import "SCShapeView.h"
@interface SCViewController () {
AVCaptureVideoPreviewLayer *_previewLayer; // 预览显示摄像内容
SCShapeView *_boundingBox; // 二维码边框视图，用于实时绘制被扫描二维码的边框
NSTimer *_boxHideTimer; // 隐藏二维码边框的计时器
UILabel *_decodedMessage; // label标签，用于显示识别出的二维码信息
}
@end
@implementation SCViewController
#pragma mark - Lifecycle
- (void)viewDidLoad {
[super viewDidLoad];
// 创建 AVCaptureSession 实例对象
AVCaptureSession *session = [[AVCaptureSession alloc] init];
// 创建输入设备：后置摄像头
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
// 创建输入对象
NSError *error = nil;
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
if(input) {
// 将输入对象添加进 Session 会话中
[session addInput:input];
} else {
NSLog(@"error: %@", error);
return;
}
// 创建并添加输出对象
// AVCaptureMetadataOutput 是 AVCaptureOutput 的子类,用于输出元数据本身
AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
// Have to add the output before setting metadata types
[session addOutput:output];
// What different things can we register to recognise?
NSLog(@"%@", [output availableMetadataObjectTypes]);
// 设置输出对象元数据类型
[output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];
// 设置代理：当前视图控制器，并在主线程调用
[output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
// 显示当前视图中的输出内容 —— 实时显示摄像内容
// AVCaptureVideoPreviewLayer 是 CALayer 的子类
_previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:session];
_previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
_previewLayer.bounds = self.view.bounds;
_previewLayer.position = CGPointMake(CGRectGetMidX(self.view.bounds), CGRectGetMidY(self.view.bounds));
[self.view.layer addSublayer:_previewLayer];
// 添加视图来绘制 UIView 的边框 —— 给二维码添加线框
_boundingBox = [[SCShapeView alloc] initWithFrame:self.view.bounds];
_boundingBox.backgroundColor = [UIColor clearColor];
_boundingBox.hidden = YES;
[self.view addSubview:_boundingBox];
// 添加标签用来显示结果数据
_decodedMessage = [[UILabel alloc] initWithFrame:CGRectMake(0, CGRectGetHeight(self.view.bounds) - 75, CGRectGetWidth(self.view.bounds), 75)];
_decodedMessage.numberOfLines = 0;
_decodedMessage.backgroundColor = [UIColor colorWithWhite:0.8 alpha:0.9];
_decodedMessage.textColor = [UIColor darkGrayColor];
_decodedMessage.textAlignment = NSTextAlignmentCenter;
[self.view addSubview:_decodedMessage];
// 运行 AVSession 会话
[session startRunning];
}
#pragma mark - AVCaptureMetadataOutputObjectsDelegate
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
for (AVMetadataObject *metadata in metadataObjects) {
if ([metadata.type isEqualToString:AVMetadataObjectTypeQRCode]) {
// 将元数据坐标转换为屏幕坐标
AVMetadataMachineReadableCodeObject *transformed = (AVMetadataMachineReadableCodeObject *)[_previewLayer transformedMetadataObjectForMetadataObject:metadata];
// Update the frame on the _boundingBox view, and show it
_boundingBox.frame = transformed.bounds;
_boundingBox.hidden = NO;
// Now convert the corners array into CGPoints in the coordinate system
// of the bounding box itself
NSArray *translatedCorners = [self translatePoints:transformed.corners
fromView:self.view
toView:_boundingBox];
// Set the corners array
_boundingBox.corners = translatedCorners;
// Update the view with the decoded text
_decodedMessage.text = [transformed stringValue];
// Start the timer which will hide the overlay
[self startOverlayHideTimer];
}
}
}
#pragma mark - Utility Methods
- (void)startOverlayHideTimer
{
// Cancel it if we're already running
if(_boxHideTimer) {
[_boxHideTimer invalidate];
}
// Restart it to hide the overlay when it fires
// 把绘制出来的线框过一段时间消失掉。
// 这就阻止了当前没有发现二维码信息的时候，线框还存在的问题。
_boxHideTimer = [NSTimer scheduledTimerWithTimeInterval:0.2
target:self
selector:@selector(removeBoundingBox:)
userInfo:nil
repeats:NO];
}
- (void)removeBoundingBox:(id)sender
{
// Hide the box and remove the decoded text
_boundingBox.hidden = YES;
_decodedMessage.text = @"";
}
/*
1.转换坐标格式
2.坐标系映射，当前页面 -> boxView
原始坐标格式：
{
X = "115.2051412322095";
Y = "135.4776067211339";
},
转换后坐标格式：
"NSPoint: {8.58306884765625e-06, 0.95792221069336847}",
*/
- (NSArray *)translatePoints:(NSArray *)points fromView:(UIView *)fromView toView:(UIView *)toView
{
NSMutableArray *translatedPoints = [NSMutableArray new];
// The points are provided in a dictionary with keys X and Y
for (NSDictionary *point in points) {
// Let's turn them into CGPoints
CGPoint pointValue = CGPointMake([point[@"X"] floatValue], [point[@"Y"] floatValue]);
// Now translate from one view to the other
CGPoint translatedPoint = [fromView convertPoint:pointValue toView:toView];
// Box them up and add to the array
[translatedPoints addObject:[NSValue valueWithCGPoint:translatedPoint]];
}
return [translatedPoints copy];
}
@end
效果
第三方的二维码开源库
- ZXingObjC——（⭐️2500+）支持多种格式的条码库。
- LBXScan —— （⭐️2000+） A barcode and qr code scanner (二维码、扫码、扫一扫、ZXing和ios系统自带扫码封装，扫码界面效果封装)(Objective-C和Swift均支持).
- 原生实现扫描二维码条码 —— iOS原生实现扫描二维码条码.
- ZFScan —— （⭐️85+）仿微信 二维码/条形码 扫描.
- QRCatcher ——（⭐️270+）完整项目，一个简洁美观的二维码扫描应用， [iOS学习：AVFoundation 视频流处理--二维码].
- BarcodeScanner —— （⭐️780+）带状态控制的条码扫描库，支持处理相机权限、自定义颜色和提示信息，不依赖其他第三方库)、Swift
- MQRCodeReaderViewController ——（⭐️352+）二维码扫描控件.
- QRWeiXinDemo —— （⭐️221+）仿微信二维码扫描，中间透明区域.
- EFQRCode ——（⭐️2084+）iOS 花式二维码生成库、Swift