how to set a function to be called after recordForDuration is crossed in iPhone AVAudioRecorder?

Question

I am using the AVAudioRecorder to record some sound from the mic. I am using [recorder recordForDuration: 10] I want to upload the sound file when 10 second is over. Is there a way to specify this ? Any help will be appreciated.

Thanks.

- ahsan

Answer 1

You can use the delegate audioRecorderDidFinishRecording:successfully: only if you send a double, float or NSTimeInterval as the duration of the recording.

These will trigger the delegate

[recorder recordForDuration:10.0]; // double
[recorder recordForDuration:10.0f]; // float

This will not trigger the delegate

[recorder recordForDuration:10]; // int

Technically, these should be of the type NSTimeInterval and not float or double.

Source: @Johnmph comment

Answer 2

Another way will be to use a Timer function ! :)

Xcode Objective-C | iOS: delay function / NSTimer help?

Answer 3

You need to set the delegate of the AVAudioRecorder object.

The delegate will receive the message audioRecorderDidFinishRecording:successfully: when the recording is done.

See documentation of AVAudioRecorder :

http://developer.apple.com/library/ios/#documentation/AVFoundation/Reference/AVAudioRecorder_ClassReference/Reference/Reference.html%23//apple_ref/occ/cl/AVAudioRecorder

and AVAudioRecorderDelegate :

http://developer.apple.com/library/ios/#documentation/AVFoundation/Reference/AVAudioRecorderDelegate_ProtocolReference/Reference/Reference.html%23//apple_ref/occ/intf/AVAudioRecorderDelegate

Answer 4

Swift code for recording for 10 seconds:

    var audioRecorder: AVAudioRecorder! 
    var meterTimer: NSTimer?

    func btnRecordAction(sender: UIButton) {

    let currentDateTime = NSDate()
    let formatter = NSDateFormatter()
    formatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
    let recordingName = formatter.stringFromDate(currentDateTime)+".m4a"
    let filePath = self.docPath!.stringByAppendingPathComponent(recordingName)

    var error: NSError?
    var session = AVAudioSession.sharedInstance()
    session.setCategory(AVAudioSessionCategoryPlayAndRecord, withOptions: .DuckOthers, error: &error)

    let recordSettings = [
        AVFormatIDKey: kAudioFormatMPEG4AAC,
        AVEncoderAudioQualityKey : AVAudioQuality.Max.rawValue,
        AVNumberOfChannelsKey: 1,
        AVSampleRateKey : 44100.0 
    ]

    let url = NSURL(fileURLWithPath: filePath)
    self.audioRecorder = AVAudioRecorder(URL: url, settings: recordSettings as! [NSObject : AnyObject] , error: &error)
    if let e = error {
        println("AVAudioRecorder error = \(e.localizedDescription)" )
    } else {
        self.audioRecorder.delegate = self
        self.audioRecorder.meteringEnabled = true
        self.audioRecorder.recordForDuration(10.0)
        self.audioRecorder.prepareToRecord()
        self.audioRecorder.record()

        if self.audioRecorder.recording == true {
            self.meterTimer = NSTimer.scheduledTimerWithTimeInterval(0.1,
                target:self,
                selector:"updateAudioMeter:",
                userInfo:nil,
                repeats:true)
        }
    }
}

func audioRecorderDidFinishRecording(recorder: AVAudioRecorder!, successfully flag: Bool) {
        println("finished recording \(flag)")


        // ios8 and later
        var alert = UIAlertController(title: "Recorder",
            message: "Finished Recording",
            preferredStyle: .Alert)
        alert.addAction(UIAlertAction(title: "Keep", style: .Default, handler: {action in
            println("keep was tapped")
        }))
        alert.addAction(UIAlertAction(title: "Delete", style: .Default, handler: {action in
            self.audioRecorder?.deleteRecording()
        }))
        self.presentViewController(alert, animated:true, completion:nil)
}

func audioRecorderEncodeErrorDidOccur(recorder: AVAudioRecorder!,
    error: NSError!) {
        println("\(error.localizedDescription)")
}

func updateAudioMeter(timer:NSTimer) {

    if  self.audioRecorder.recording {
        let dFormat = "%02d"
        let min:Int = Int(self.audioRecorder.currentTime / 60)
        let sec:Int = Int(self.audioRecorder.currentTime % 60)
        let s = "Recording: \(String(format: dFormat, min)):\(String(format: dFormat, sec)) secs"
        self.lblRecorderTime!.text = s
        self.audioRecorder.updateMeters()

    }

}