实现长按识别webview中的二维码

@property (nonatomic,copy) NSString *imgURL; UIWebView *_web; NSInteger _gesState; - (void)webViewDidFinishLoad:(UIWebView *)webView{ [MBProgressHUD hideHUD]; //实现图片长按识别功能 static NSString* const kTouchJavaScriptString= @"document.ontouchstart=function(event){\ x=event.targetTouches[0].clientX;\ y=event.targetTouches[0].clientY;\ document.location=\"myweb:touch:start:\"+x+\":\"+y;};\ document.ontouchmove=function(event){\ x=event.targetTouches[0].clientX;\ y=event.targetTouches[0].clientY;\ document.location=\"myweb:touch:move:\"+x+\":\"+y;};\ document.ontouchcancel=function(event){\ document.location=\"myweb:touch:cancel\";};\ document.ontouchend=function(event){\ document.location=\"myweb:touch:end\";};"; [webView stringByEvaluatingJavaScriptFromString:kTouchJavaScriptString];//注入js方法 } - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType { // add by zcj 实现图片长按识别功能 NSString *requestString = request.URL.absoluteString; NSArray *components = [requestString componentsSeparatedByString:@":"]; if ([components count] > 1 && [(NSString *)[components objectAtIndex:0] isEqualToString:@"myweb"]) { if([(NSString *)[components objectAtIndex:1] isEqualToString:@"touch"]) { //NSLog(@"you are touching!"); if ([(NSString *)[components objectAtIndex:2] isEqualToString:@"start"]) { _gesState = UIGestureRecognizerStateBegan; float ptX =[[components objectAtIndex:3]floatValue]; float ptY =[[components objectAtIndex:4]floatValue]; NSString *js = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).tagName", ptX, ptY]; NSString * tagName = [_web stringByEvaluatingJavaScriptFromString:js]; if ([tagName isEqualToString:@"IMG"]) { self.imgURL = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src", ptX, ptY]; } if (self.imgURL) { [self performSelector:@selector(handleLongTouch) withObject:nil afterDelay:1.0]; } } else if ([(NSString *)[components objectAtIndex:2] isEqualToString:@"move"]) { _gesState = UIGestureRecognizerStateChanged; } } else if ([(NSString*)[components objectAtIndex:2]isEqualToString:@"end"]) { _gesState = UIGestureRecognizerStateEnded; } }// ]end return YES; } - (void)handleLongTouch { if (self.imgURL && _gesState == UIGestureRecognizerStateBegan) { UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet]; NSString *urlToSave = [_web stringByEvaluatingJavaScriptFromString:self.imgURL]; NSData* data = [NSData dataWithContentsOfURL:[NSURL URLWithString:urlToSave]]; UIImage* image = [UIImage imageWithData:data]; NSDictionary *options = [[NSDictionary alloc] initWithObjectsAndKeys: @"CIDetectorAccuracy", @"CIDetectorAccuracyHigh",nil]; CIDetector *detector = nil; if ([[UIDevice currentDevice].systemVersion floatValue] >= 8.0) detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:options]; NSArray *features = [detector featuresInImage:[CIImage imageWithCGImage:image.CGImage]] ; // 识别图中二维码 UIAlertAction *judgeCode = [UIAlertAction actionWithTitle:@"识别图中二维码" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) { CIQRCodeFeature *feature = [features objectAtIndex:0]; NSString *scannedResult = feature.messageString; if ([[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:scannedResult]]){ [[UIApplication sharedApplication] openURL:[NSURL URLWithString:scannedResult]]; }else{ [MBProgressHUD showError:@"无法识别的网址"]; } }]; // 保存图片到手机 UIAlertAction *saveImage = [UIAlertAction actionWithTitle:@"保存到手机" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) { UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil); }]; // 取消 UIAlertAction *cancell = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) { }]; if (features.count >= 1) { [alertController addAction:judgeCode]; } [alertController addAction:saveImage]; [alertController addAction:cancell]; [self presentViewController:alertController animated:YES completion:nil]; } }