AVCaptureLocation/AAPLViewController.m

/*
 Copyright (C) 2014 Apple Inc. All Rights Reserved.
 See LICENSE.txt for this sample’s licensing information
 
 Abstract:
 
 View controller for the camera interface and selecting location capture mode.
  
 */
 
#import "AAPLViewController.h"
#import "AAPLCaptureManager.h"
 
@import AssetsLibrary;
 
@interface AAPLViewController () <AAPLCaptureManagerDelegate>
{
    AAPLCaptureManager              *_captureManager;
    UIBackgroundTaskIdentifier      _backgroundRecordingID;
}
 
@property IBOutlet UIView               *previewView;
@property IBOutlet UIBarButtonItem      *recordButton;
@property IBOutlet UISegmentedControl   *locationUpdateModeButton;
@property IBOutlet UILabel              *currentLocation;
 
- (IBAction)toggleLocationUpdateMode:(id)sender;
- (IBAction)toggleRecording:(id)sender;
 
@end
 
@implementation AAPLViewController
 
#pragma mark - View Loading
 
- (void)viewDidLoad
{
    [super viewDidLoad];
    
    // Initialize the class responsible for managing AV capture session and asset writer
    _captureManager = [[AAPLCaptureManager alloc] init];
    _captureManager.delegate = self;
    
    //Set default distance senstivity to 5 meters, which for this sample code purpose is considered as sensitivity for walking
    _captureManager.distanceUpdateInMeters = 5.0;
    
    // Keep track of changes to the device orientation so we can update the capture manager
    NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
    [notificationCenter addObserver:self selector:@selector(deviceOrientationDidChange) name:UIDeviceOrientationDidChangeNotification object:nil];
    [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
    
    // Setup and start the capture session
    [_captureManager setupAndStartCaptureSession];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationDidBecomeActive:) name:UIApplicationDidBecomeActiveNotification object:[UIApplication sharedApplication]];
    
    // Setup preview layer
    if (_captureManager.session)
    {
        AVCaptureVideoPreviewLayer *layer = [AVCaptureVideoPreviewLayer layerWithSession:_captureManager.session];
        layer.videoGravity = AVLayerVideoGravityResizeAspect;
        layer.frame = self.previewView.bounds;
        [self.previewView.layer addSublayer:layer];
    }
}
 
- (void)viewDidUnload
{
    [super viewDidUnload];
    
    [self cleanup];
}
 
- (void)cleanup
{
    NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
    [notificationCenter removeObserver:self name:UIDeviceOrientationDidChangeNotification object:nil];
    [[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];
    
    [notificationCenter removeObserver:self name:UIApplicationDidBecomeActiveNotification object:[UIApplication sharedApplication]];
    
    // Stop and tear down the capture session
    [_captureManager stopAndTearDownCaptureSession];
    _captureManager.delegate = nil;
}
 
- (void)applicationDidBecomeActive:(NSNotification*)notifcation
{
    // For performance reasons, we manually pause/resume the session when saving a recording.
    // If we try to resume the session in the background it will fail. Resume the session here as well to ensure we will succeed.
    [_captureManager resumeCaptureSession];
}
 
- (void)deviceOrientationDidChange
{
    UIDeviceOrientation orientation = [UIDevice currentDevice].orientation;
    // Don't update the reference orientation when the device orientation is face up/down or unknown.
    if (UIDeviceOrientationIsPortrait(orientation) || UIDeviceOrientationIsLandscape(orientation))
        [_captureManager setReferenceOrientation:(AVCaptureVideoOrientation)orientation];
}
 
#pragma mark - IBActions
 
- (IBAction)toggleRecording:(id)sender
{
    // Wait for the recording to start/stop before re-enabling the record button.
    self.recordButton.enabled = NO;
        
    if ([_captureManager isRecording])
    {
        // The recordingWill/DidStop delegate methods will fire asynchronously in response to this call
        [_captureManager stopRecording];
    }
    else
    {
        // The recordingWill/DidStart delegate methods will fire asynchronously in response to this call
        [_captureManager startRecording];
    }
}
 
- (IBAction)toggleLocationUpdateMode:(id)sender
{
    if(_locationUpdateModeButton.selectedSegmentIndex == 0) // Walking - set distance sensitibity to 5 meters
    {
        _captureManager.distanceUpdateInMeters = 5.0;
    }
    else // Driving - set distance sensitivity to 20 meters
    {
        _captureManager.distanceUpdateInMeters = 20.0;
    }
}
 
#pragma mark - AVCLVideoProcessorDelegate
 
- (void)recordingWillStart
{
    dispatch_async(dispatch_get_main_queue(), ^{
        self.recordButton.enabled = NO;
        self.recordButton.title = @"Stop";
        self.locationUpdateModeButton.enabled = NO;
        
        // Disable the idle timer while we are recording
        [UIApplication sharedApplication].idleTimerDisabled = YES;
        
        // Make sure we have time to finish saving the movie if the app is backgrounded during recording
        if ([UIDevice currentDevice].multitaskingSupported)
            _backgroundRecordingID = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{}];
    });
}
 
- (void)recordingDidStart
{
    dispatch_async(dispatch_get_main_queue(), ^{
        // Enable the stop button now that the recording has started
        self.recordButton.enabled = YES;
    });
}
 
- (void)recordingWillStop
{
    dispatch_async(dispatch_get_main_queue(), ^{
        // Disable until saving to the camera roll is complete
        self.recordButton.title = @"Record";
        self.recordButton.enabled = NO;
        self.locationUpdateModeButton.enabled = NO;
        
        // Pause the capture session so that saving will be as fast as possible.
        // We resume the sesssion in recordingDidStop:
        [_captureManager pauseCaptureSession];
    });
}
 
- (void)recordingDidStop
{
    dispatch_async(dispatch_get_main_queue(), ^{
        // Enable record and update mode buttons
        self.recordButton.enabled = YES;
        self.locationUpdateModeButton.enabled = YES;
        [self newLocationUpdate:@""]; // clear out the current location label
        
        [UIApplication sharedApplication].idleTimerDisabled = NO;
        
        [_captureManager resumeCaptureSession];
        
        if ([UIDevice currentDevice].multitaskingSupported)
        {
            [[UIApplication sharedApplication] endBackgroundTask:_backgroundRecordingID];
            _backgroundRecordingID = UIBackgroundTaskInvalid;
        }
    });
}
 
- (void)newLocationUpdate:(NSString *)locationDescription
{
    // Use this method to update the label which indicates the current location
    self.currentLocation.textColor = [UIColor colorWithWhite:1.0 alpha:1.0];
    self.currentLocation.text = locationDescription;
}
@end


Copyright © 2014 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2014-09-17