ios - iPhone 5 真机下 使用扫一扫功能 扫描二维码,用苹果自带正则表达式却崩溃了

Answer 1

Apple Documentation:

"This method may be called frequently, your implementation should be efficient to prevent capture performance problems, including dropped metadata objects."

So the matter of controlling the number of scans needs to be handled by our developers. . .

Answer 2

I don’t know why the scan function of iPhone5 is different from other models. The camera function of iPhone5 will call this method repeatedly when it is not completely exited
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection,

The stringValue scanned out is a URL

NSTextCheckingResult * firstWebUrl = [regex firstMatchInString:stringValue options:0 range:NSMakeRange(0, [stringValue length])];

However, if you call multiple times, null values ​​will be swept out, and stringValue will become null, causing a crash