ios APPweb网页长按识别二维码和保存图片
知识点：oc和js的交互 、系统原生类二维码识别
核心思想：通过oc向web网页注入js代码以获取网页中的图片。获取图片后再进行二维码识别、保存图片等操作。
具体实现：
1、给webview添加长按手势
UILongPressGestureRecognizer* longPressed = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressed:)];
longPressed.delegate = self;
[self.webView addGestureRecognizer:longPressed];
2、实现长按方法， 在长按方法中注入js 获取图片（获取的时图片的URL， 就是image标签里的 src）- (void)longPressed:(UILongPressGestureRecognizer*)recognizer
{
if (recognizer.state != UIGestureRecognizerStateBegan) {
return;
}
CGPoint touchPoint = [recognizer locationInView:self.webView];
// 获取手势所在图片的URL，js中图片的地址是用src引用的
NSString *imgURL = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src", touchPoint.x, touchPoint.y];
NSString *urlToSave = [self.webView stringByEvaluatingJavaScriptFromString:imgURL];
if (urlToSave.length == 0) {
return;
}
[self showImageOptionsWithUrl:urlToSave];
}
3、实现showImageOptionsWithUrl方法， 通过url加载图片，进行二维码码识别，保存图片
- (void)showImageOptionsWithUrl:(NSString *)imgURL
{
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
NSData* data = [NSData dataWithContentsOfURL:[NSURL URLWithString:imgURL]];
UIImage* image = [UIImage imageWithData:data];
NSDictionary *options = [[NSDictionary alloc] initWithObjectsAndKeys:
@"CIDetectorAccuracy", @"CIDetectorAccuracyHigh",nil];
CIDetector *detector = nil;
//if (IOS8_Later)
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]]){
NSLog(@"scannedResult = %@", scannedResult);
}else{
NSLog(@"无法识别的网址");
[SVProgressHUD showErrorWithStatus:@"无法识别的网址"];
}
}];
// 保存图片到手机
UIAlertAction *saveImage = [UIAlertAction actionWithTitle:@"保存图片到手机" 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];
}
4 、补充
// 功能：显示图片保存结果
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError*)error contextInfo:(void*)contextInfo
{
if (error){
NSLog(@"保存图片失败");
}else {
NSLog(@"保存图成功");
}
}
以上，代码是偷来的，思想是自己总结的。。