Audio app

To play audio on the phone, we will need to add the AVFoundation.framework to our XCode created project.
We also need to drag our audio file, say an .mp3 into our resources folder.

Here is what our header file will look like:

#import <UIKit/UIKit.h>

#import <AVFoundation/AVFoundation.h>

@interface  AudioTestIPhoneViewController : UIViewController {
	IBOutlet UIButton *playButton;
	IBOutlet UIButton *stopButton;
	AVAudioPlayer *audioPlayer;
}

@property (nonatomic, retain) IBOutlet UIButton *playButton;
@property (nonatomic, retain) IBOutlet UIButton *stopButton;
@property (nonatomic, retain) AVAudioPlayer *audioPlayer;

-(IBAction)play;
-(IBAction)stop;

@end

The XIB file and Implementation

For the XIB file we drag over two buttons and connect them up with the play and stop functions from the previous slide.

Finally, our implementation file looks like:

//
//  AudioTestIPhoneViewController.m
//  AudioTestIPhone
//
//  Created by Chris Pollett on 12/1/10.
//  Copyright 2010 San Jose State University. All rights reserved.
//

#import "AudioTestIPhoneViewController.h"

@implementation AudioTestIPhoneViewController
@synthesize playButton;
@synthesize stopButton;
@synthesize audioPlayer;

- (void)viewDidLoad {
	[super viewDidLoad];
	
	// Get the file path to the song to play.
	NSString *filePath = [[NSBundle mainBundle] pathForResource:@"warworlds"
														 ofType:@"mp3"];
	
	// Convert the file path to a URL.
	NSURL *fileURL = [[NSURL alloc] initFileURLWithPath:filePath];
	
	//Initialize the AVAudioPlayer.
	self.audioPlayer = [[AVAudioPlayer alloc]
						initWithContentsOfURL:fileURL error:nil];
	
	// Preloads the buffer and prepares the audio for playing.
	[self.audioPlayer prepareToPlay];
	
	[filePath release];
	[fileURL release];
	
}

-(IBAction)play {
	
	// Make sure the audio is at the start of the stream.
	self.audioPlayer.currentTime = 0;
	
	[self.audioPlayer play];
	
}

-(IBAction)stop {
	
	[self.audioPlayer stop];
	
}



- (void)dealloc {
    [super dealloc];
}

@end

Quiz

Which of the following is true?

When handling touch events for iPhone one can figure out which touches occurred in a view using the touchesForView message.
Only Activity's in Android can implement OnTouchListener.
The video tag cannot be used with Javascript.

VideoDemoViewController.m

A similar approach is used to play video. The iPhone can be a little bit fussy about the video files it is willing to play:

//
//  VideoDemoViewController.m
//  VideoDemo
//
//  Created by Chris Pollett on 12/1/10.
//  Copyright 2010 San Jose State University. All rights reserved.
//

#import "VideoDemoViewController.h"

#import <MediaPlayer/MediaPlayer.h>

@implementation VideoDemoViewController

- (void)viewDidLoad {
    
    NSString *url = [[NSBundle mainBundle] 
					 pathForResource:@"fredott" 
					 ofType:@"mp4"];
	
    MPMoviePlayerController *player = 
	[[MPMoviePlayerController alloc] 
	 initWithContentURL:[NSURL fileURLWithPath:url]];
    
    [[NSNotificationCenter defaultCenter] 
	 addObserver:self
	 selector:@selector(movieFinishedCallback:)                                                 
	 name:MPMoviePlayerPlaybackDidFinishNotification
	 object:player];
    
    //---play movie---
    [player play];    
    [super viewDidLoad];    
}

- (void) movieFinishedCallback:(NSNotification*) aNotification {
    MPMoviePlayerController *player = [aNotification object];
    [[NSNotificationCenter defaultCenter] 
	 removeObserver:self
	 name:MPMoviePlayerPlaybackDidFinishNotification
	 object:player];    
    [player autorelease];    
}

@end

The Camera and Photo Library

iPhone applications are sandboxed.
Because of this, applications can't typically get to photographs or other data outside of their application.
Nevertheless, the camera and photo library are made available by way of an image picker.
This provides a mechanism that lets you select an image from a specified source.
Image pickers are implemented via a modal controller class called UIImagePickerController.
To create an instance of this class, you need to specify a delegate class, specify its image source, and then launch it modally,
The image picker will then take control of the iPhone to let the user select a picture or take it.
Regardless of whether an image is selected or cancelled, the delegate has the responsibility to dismiss the UIImagePickerController, so that the user can return to your app.
The possible source types for a UIImagePickerController are: UIImagePickerControllerSourceTypeCamera, UIImagePickerControllerSourceTypeSavedPhotosAlbum, UIImagePickerControllerSourceTypePhotoLibrary.
We will now create a small app to demo these things.

CameraIPhoneViewController.h

//
//  CameraIPhoneViewController.h
//  CameraIPhone
//
//  Created by Chris Pollett on 12/1/10.
//  Copyright 2010 San Jose State University. All rights reserved.
//

#import 

@interface CameraIPhoneViewController : UIViewController 
 <UIImagePickerControllerDelegate, UINavigationControllerDelegate> {
	 IBOutlet UIImageView *imageView;
	 IBOutlet UIButton *takePictureButton;
	 IBOutlet UIButton *selectFromCameraRollButton;
}
@property (nonatomic, retain) UIImageView *imageView;
@property (nonatomic, retain) UIButton *takePictureButton;
@property (nonatomic, retain) UIButton *selectFromCameraRollButton;
- (IBAction)getCameraPicture:(id)sender;
- (IBAction)selectExistingPicture;
@end

The XIB file

For the XIB file we drag over an image view to hold the camera scene, and we put three buttons beneath it.
We label these: Take New Picture, Pick from Camera Roll, and Pick From Library.
We hook up these buttons to the functions of the previous slide.

CameraIPhoneViewController.m

//
//  CameraIPhoneViewController.m
//  CameraIPhone
//
//  Created by Chris Pollett on 12/1/10.
//  Copyright 2010 San Jose State University. All rights reserved.
//

#import "CameraIPhoneViewController.h"

@implementation CameraIPhoneViewController
@synthesize imageView;
@synthesize takePictureButton;
@synthesize selectFromCameraRollButton;

- (void)viewDidLoad {
   if(![UIImagePickerController 
		isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
	   takePictureButton.hidden = YES;
	   selectFromCameraRollButton.hidden = YES;
   }
}

 // Override to allow orientations other than the default portrait orientation.
 - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
 // Return YES for supported orientations
 return (interfaceOrientation == UIInterfaceOrientationPortrait);
 }

- (void)didReceiveMemoryWarning {
	// Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
	
	// Release any cached data, images, etc that aren't in use.
}


- (void)dealloc {
	[imageView release];
	[takePictureButton release];
	[selectFromCameraRollButton release];
    [super dealloc];
}

#pragma mark -
-(IBAction)getCameraPicture: (id)sender {
	UIImagePickerController *picker = [[UIImagePickerController alloc] init];
	picker.delegate = self;
	picker.allowsImageEditing = YES;
	picker.sourceType = (sender == takePictureButton) ?
		UIImagePickerControllerSourceTypeCamera :
		UIImagePickerControllerSourceTypeSavedPhotosAlbum;
	[self presentModalViewController:picker animated: YES];
	[picker release];
}

-(IBAction)selectExistingPicture {
	if([UIImagePickerController isSourceTypeAvailable:
		UIImagePickerControllerSourceTypePhotoLibrary]) {
		UIImagePickerController *picker = 
			[[UIImagePickerController alloc] init];
		picker.delegate = self;
		picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
		[self presentModalViewController:picker animated:YES];
		[picker release];
	} else {
		UIAlertView *alert = [[UIAlertView alloc]
			initWithTitle:@"Error accessing photo library" 
			message:@"Device does not support a photo library" 
			delegate:nil 
			cancelButtonTitle:@"Darn!" 
							  otherButtonTitles:nil];
		[alert show];
		[alert release];
	}
}

-(void)imagePickerController:(UIImagePickerController *)picker
		didFinishPickingImage:(UIImage *)image
				 editingInfo:(NSDictionary *)editingInfo {
	imageView.image = image;
	UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
	[picker dismissModalViewControllerAnimated:YES];
}

-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
	[picker dismissModalViewControllerAnimated:YES];
}

@end

Multimedia on iPhone

Outline