Use long press gesture with AVFoundation to start stop recording

Question

Hi I would like to start stop a recording with AVFoundation coding in Objective-C with long press gesture.

I know how to start a recording and stop it with another button, but not doing it all with the same one.

Thanks!

Answer 1

I changed your code in github very little and posted the code below. The reason i added the UIGestureRecognizerDelegate is because otherwise your PLAYBUTTONs clicks are ignored because of the long press gesture. And i changed [gesture1 setMinimumPressDuration:0]; to 0 seconds for avoiding a delay.

When I run the project it works perfectly as you have asked:) Here is the .h

//viewcontroller.h
#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#import <CoreAudio/CoreAudioTypes.h>
@interface ViewController : UIViewController  <AVAudioRecorderDelegate, AVAudioPlayerDelegate, UIGestureRecognizerDelegate>
@property (weak, nonatomic) IBOutlet UIButton *playButton;
- (void)longPressed:(UIGestureRecognizer *)longPress;
- (IBAction)playTapped:(id)sender;
@end

Here is the implementation:

//viewcontroller.m
#import "ViewController.h"

@interface ViewController ()
{
    AVAudioRecorder *recorder;
    AVAudioPlayer *player;
}
@end

@implementation ViewController
@synthesize playButton;

- (void)viewDidLoad
{

    UILongPressGestureRecognizer *gesture1 = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressed:)];
    gesture1.delegate = self;
    [gesture1 setMinimumPressDuration:0];
    [self.view addGestureRecognizer:gesture1];


    [super viewDidLoad];

    // Disable Stop/Play button when application launches
    [playButton setEnabled:NO];

    // Set the audio file
    NSArray *pathComponents = [NSArray arrayWithObjects:
                               [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject],
                               @"MyAudioMemo.m4a",
                               nil];
    NSURL *outputFileURL = [NSURL fileURLWithPathComponents:pathComponents];

    // Setup audio session
    AVAudioSession *session = [AVAudioSession sharedInstance];
    [session setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];

    // Define the recorder setting
    NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init];

    [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];
    [recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
    [recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];

    // Initiate and prepare the recorder
    recorder = [[AVAudioRecorder alloc] initWithURL:outputFileURL settings:recordSetting error:nil];
    recorder.delegate = self;
    recorder.meteringEnabled = YES;
    [recorder prepareToRecord];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)longPressed:(UIGestureRecognizer *)longPress {
    if(([longPress state] == UIGestureRecognizerStateEnded) || ([longPress state] == UIGestureRecognizerStateEnded)) {
        NSLog(@"long press ended");
        [recorder stop];
        AVAudioSession *audioSession = [AVAudioSession sharedInstance];
        [audioSession setActive:NO error:nil];
    }
    else if([longPress state] == UIGestureRecognizerStateBegan) {
        NSLog(@"long press detected");

        if (player.playing) {
            [player stop];
        }

        if (!recorder.recording) {
            AVAudioSession *session = [AVAudioSession sharedInstance];
            [session setActive:YES error:nil];

            // Start recording
            [recorder record];
        }
    }
}


- (IBAction)playTapped:(id)sender {
    NSLog(@"playTapped");
    if (!recorder.recording){
        player = [[AVAudioPlayer alloc] initWithContentsOfURL:recorder.url error:nil];
        [player setDelegate:self];
        [player play];
    }
}

#pragma mark - AVAudioRecorderDelegate

- (void) audioRecorderDidFinishRecording:(AVAudioRecorder *)avrecorder successfully:(BOOL)flag{
    NSLog(@"audioRecorderDidFinishRecording");
    [playButton setEnabled:YES];
}

#pragma mark - AVAudioPlayerDelegate

- (void) audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle: @"Done"
                                                    message: @"Finish playing the recording!"
                                                   delegate: nil
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil];
    [alert show];
}

#pragma mark - UIGestureRecognizerDelegate

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
    // test if our control subview is on-screen
    if (playButton.superview != nil) {
        if ([touch.view isDescendantOfView:playButton]) {
            // we touched our control surface
            return NO; // ignore the touch
        }
    }
    return YES; // handle the touch
}


@end

Answer 2

You can setup a UILongPressGestureRecognizer simply like this inside

- (void) viewDidLoad {....}

UILongPressGestureRecognizer *gesture1 = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressed:)];
//[gesture1 setDelegate:self]; you won't need this most probably if detecting the long press is your only expectation from the gesture recognizer
[gesture1 setMinimumPressDuration:1];
[self addGestureRecognizer:gesture1];
//instead of [self addGest... you can try [self.view addGest.. as follows:
[self.view addGestureRecognizer:gesture1];

and when the user presses the view for at least 1 seconds this function is fired:

-(void)longPressed:(UIGestureRecognizer *)longPress {
    if(([longPress state] == UIGestureRecognizerStateEnded) || ([longPress state] == UIGestureRecognizerStateEnded)) {
        NSLog(@"long press ended");
        //[self stopRecording];
    }
    else if([longPress state] == UIGestureRecognizerStateBegan) {
        NSLog(@"long press detected");
        //[self startRecording];
    }
}

instead of the old way you were using with the UIButton:

-(IBAction) buttonPressed: (id)sender {
    NSLog(@"button press detected");
    //[self startRecording];
}