Audio not playing until moving the camera away from Qr code - iOS

Question

I am new to iOS development and I am developing an app in which I want to play some audios when the QR code gets detected. I am able to detect the QR code and also play the audios but the thing is the audio-only plays when I move the camera away from QR code. So, if I am pointing the camera towards QR code it does not play the audio but as soon as I move the camera (i.e. no QR code is getting detected) the audio starts playing. I don't want this behavior I want audio to play as soon as QR code gets detected. Any suggestion would be great as I have just started iOS development 2 3 days back. Thanks.

-(void)captureOutput:(AVCaptureOutput *)captureOutput
didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection(AVCaptureConnection *)connection{



NSString *detected=@"";



if (metadataObjects != nil && [metadataObjects count] > 0) {



    AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];



    if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]) {


        detected=[NSString stringWithString:[metadataObj stringValue]];

        NSString *path =  [[NSBundle mainBundle] pathForResource:@"cbp"  ofType:@"mp3"];

        NSURL *url = [NSURL URLWithString:path];



        _audioPlayer = [[AVAudioPlayer alloc]initWithContentsOfURL:url error:NULL];


        [_audioPlayer play];


    }



}

}

Answer 1

Don't initialise the AVAudioPlayer in this AVFoundation delegate method, Load the player with sound file before scanning start.

(void)loadSound{
    NSString *beepFilePath = [[NSBundle mainBundle] pathForResource:@"cbp" ofType:@"mp3"];
    NSURL *beepURL = [NSURL URLWithString:beepFilePath];
    NSError *error;

    _audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:beepURL error:&error];
    if (error) {
        NSLog(@"Could not play sound file.");
        NSLog(@"%@", [error localizedDescription]);
    }
    else{
        [_audioPlayer prepareToPlay];
    }
}

You can call loadSound() function in viewWillAppear() method.And your AVFoundation delegate method will look like this:-

(void)captureOutput:(AVCaptureOutput *)captureOutput
didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection(AVCaptureConnection *)connection{
NSString *detected=@"";

if (metadataObjects != nil && [metadataObjects count] > 0) {

    AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];

    if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]) {
        detected=[NSString stringWithString:[metadataObj stringValue]];    

        if (_audioPlayer) {
            [_audioPlayer play];
        }
    }
}
}

try this.