Recap: Android Components - PowerPoint Presentation

Slide1

Recap: Android Components

Application= Set of Android Components

UI Component typically corresponding to one screen.

Activity

Responds to notifications or status changes. Can wake up your process.

BroadcastReceiver

Faceless task that runs in the background.

Service

Enable applications to share data.

ContentProvider

Intent

Slide2

Android

ProgrammingLecture 10

Multimedia

Slide3

3

Slide4

4

The Android multimedia framework includes support for playing variety of common media types, so that you can easily integrate audio, video and images into your applications.

Audio

MP3

MIDI

PCM/WAVE

AAC LCetc…

Video

H.263H.264 AVCMPEG-4etc…

Slide5

Media Playback

5Android multimedia framework includes support for playing variety of common media types, so that you can easily integrate audio, video

and images into your applications.

You can play audio or video from media files stored in your application’s resources (raw resources), from standalone files in the file system, or from a data stream arriving over a network connection, all using MediaPlayer class

Slide6

Media Playback Guide

http://developer.android.com/guide/topics/media/mediaplayer.html6

Slide7

Media PlayerOne of the most important components of the media framework is the

MediaPlayer class. An object of this class can fetch, decode, and play both audio and video with minimal setup. It supports several different media sources such as:

Local resourcesInternal URIs, such as one you might obtain from a Content ResolverExternal URIs (streaming)Supported Media Formats are:RTSP (RTP, SDP)HTTP/HTTPS progressive streamingHTTP/HTTPS live streaming 3GPPMPEG-4MP37

Slide8

8

// Create an instance of

MediaPlayer and load the musicMediaPlayer mediaPlayer = MediaPlayer.create(this, R.raw.

music);// Start the media playbackmediaPlayer.start();

Step 1: Create the raw folder in the project and put the media file into the folder

Step 2: Configure the media player object to start the media playback

To replay the media, call reset() and

prepare()To pause, call pause()To stop, call stop()MediaPlayer class reference: http://developer.android.com/reference/android/media/MediaPlayer.html

Slide9

Media Player

Whit this example you can play an audio file as a local raw resource from res/raw/ directory:You can also load a local content through an URI Object

You can also play a content from a remote URL via HTTP streaming.9MediaPlayer

mediaPlayer = MediaPlayer.create(context, R.raw.sound_file_1);mediaPlayer.start(); // no need to call prepare(); create() does that for you

String url = "http://........"; // your URL here

MediaPlayer mediaPlayer = new MediaPlayer();

mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);mediaPlayer.setDataSource

(url);mediaPlayer.prepare(); // might take long! (for buffering, etc)

mediaPlayer.start();

Uri myUri = ....; // initialize Uri hereMediaPlayer mediaPlayer = new MediaPlayer();mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC

);

mediaPlayer.setDataSource(getApplicationContext(), myUri);

mediaPlayer.prepare();

mediaPlayer.start();

Slide10

Read Media Information

10

Slide11

Callback Functions

11

setOnBufferingUpdateListener This method can be called in any state and calling it does not change the object state. setOnCompletionListener This method can be called in any state and calling it does not change the object state.

setOnErrorListener This method can be called in any state and calling it does not change the object state. setOnPreparedListener This method can be called in any state and calling it does not change the object state. setOnSeekCompleteListener This method can be called in any state and calling it does not change the object state.

Slide12

Task at home

12Follow this tutorial to make a cool

sound equalizer: http://www.101apps.co.za/articles/perfect-sound-using-the-equalizer-effect-a-tutorial.html

Slide13

Audio Recording

13

Slide14

Audio Capture

You can record audio using the MediaRecorder

APIs if supported by the device hardwareEmulator does not have the capability to record audio and video14MediaRecorder class reference: http://developer.android.com/reference/android/media/MediaRecorder.html

Slide15

Media Recorder

15

Create a new instance of android.media.MediaRecorder. Set the audio source using MediaRecorder.setAudioSource(). You will probably want to use microphone with MediaRecorder.AudioSource.MIC

Set output file format using

MediaRecorder.setOutputFormat(). Set output file name using MediaRecorder.setOutputFile().

Set the audio encoder using MediaRecorder.setAudioEncoder(). Call MediaRecorder.prepare() on the MediaRecorder instance. To start audio capture, call MediaRecorder.start().

To stop audio capture, call MediaRecorder.stop(). When you are done with the MediaRecorder instance, call MediaRecorder.release() on it to release the resource. http://developer.android.com/guide/topics/media/audio-capture.html

Slide16

16

private

void startRecording() { // 1. Create a new instance of android.media.MediaRecorder MediaRecorder mRecorder = new MediaRecorder();

// 2. Set the audio source using MediaRecorder.setAudioSource() // In this example, use microphone to get audio mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC); // 3. Set output file format using MediaRecorder.setOutputFormat(). mRecorder

.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP); // 4. Set output file name using MediaRecorder.setOutputFile(). mRecorder.setOutputFile(“/sdcard/myaudio.3gp

”); // 5. Set the audio encoder using MediaRecorder.setAudioEncoder(). mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB); // 6. Call MediaRecorder.prepare() on the MediaRecorder

instance. try { mRecorder.prepare(); } catch (IOException e) { Log.e(LOG_TAG, "prepare() failed"

); } // 7. To start audio capture, call MediaRecorder.start(). mRecorder.start(); } private void stopRecording() { // 8. To stop audio capture, call

MediaRecorder.stop(). mRecorder.stop(); // 9. call MediaRecorder.release() on it to release the resource. mRecorder.release(); mRecorder =

null; }

Slide17

Things to Remember: Manifest

17

<manifest . . . > . . . <uses-permission android:name="android.permission.RECORD_AUDIO

"/> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> . . .</manifest

>The application needs to have the permission to write to external storage if the output file is written to the external storage, and also the permission to record audio. These permissions must be set in the application's AndroidManifest.xml file, with something like:

Slide18

SoundPool

Multiple sounds can be played from raw or compressed sourceA SoundPool is a collection of samples that can be loaded into memory from a resource inside the APK or from a file in the file systemMore efficient than media player in terms of CPU load, latency

Adjustable playback frequencyEach sound can be assigned a prioritySupport for repeat mode18SoundPool class reference: http://developer.android.com/reference/android/media/SoundPool.html

Slide19

Creating Sound Effects

SoundPool is designed for short files which can be kept in memory decompressed for quick access, this is best suited for sound effects in apps and games

Media Player is designed for longer sound files or streams, this is best suited for music files or larger files. The files will be loaded disk each time created is called, this will save on memory space but introduce a small delay (not really noticeable)19Refer to the video for a comparison between the two classeshttps://www.youtube.com/watch?v=bcYX5fa_jFcSoundPool

MediaPlayer

Slide20

20

soundPool.play(soundId, 

1f, 1f, 1, 0, 1f); Constructs a SoundPool with the maximum number of simultaneous streams and Audio stream type.

Play the music clip• soundID – Sound ID returned by the load() function• leftVolume – Left volume value (0.0 ~ 1.0)• rightVolume

– right volume value (0.0 ~ 1.0)• priority – stream priority (0 = lowest priority)• loop – loop mode (0 = no loop, -1 = loop forever)• rate – playback rate (0.5 ~ 2.0, 1.0 = normal playback)

Load the sound from the specified resource.SoundPool class reference: http://developer.android.com/reference/android/media/SoundPool.htmlint soundId = mSoundPool.load(this, R.raw.b1, 1); SoundPool 

soundPool = new SoundPool(4, AudioManager.STREAM_MUSIC, 0);

Slide21

Task at home

21

In assignment 1 game, ask the player to record the short sound, and use the sound in the game, like when the ball hits the paddle and bounces

Slide22

Video

22

Slide23

VideoView

VideoView is a View that has video playback capabilities and can be used directly in a

layoutIt is a View working with media playerThe VideoView class can load images from various sources (such as resources or content providers), takes care of computing its measurement from the video so that it can be used in any layout manager, and provides various display options such as scaling and tintingWe can then add controls (play, pause, forward, back, etc) with the MediaController class.23

Slide24

Video View

Add VideoView

component on layout file Set content on VideoViewsetVideoURI(...)setVideoPath(...)Use start(), stop(), etc. to control video. main_layout.xml

MainActivity.java

Slide25

Callback Functions

setOnPreparedListener ->

onPrepared()Called when VideoView is prepared for play.Use when waiting contents on online to be prepared.setOnCompletionListener -> onCompletion()Called when VideoView playback is completed

Slide26

Using Native App

Invoke the video playback by using the common intentRemember, your app is now in the background.

26Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(srcPath));intent.setDataAndType(Uri.parse(srcPath), "video/mp4");startActivity(intent);

Slide27

Camera

27

Slide28

CameraThe Android framework includes support for various cameras and camera features available on devices, allowing you to capture pictures and videos in your applications.

The Android framework supports capturing images and video through the Camera API or camera Intent.

28

Slide29

Camera

Camera

This class is the primary API for controlling device cameras. This class is used to take pictures or videos when you are building a camera application.MediaRecorderThis class is used to record video from the camera.Intent An intent action type of MediaStore.ACTION_IMAGE_CAPTURE or MediaStore.ACTION_VIDEO_CAPTURE can be used to capture images or videos without directly using the Camera object.

29

Slide30

Image Capture Intent

Capturing images using a camera intent is quick way to enable your application to take pictures with minimal coding. An image capture intent can include the following extra information

30private static final int

CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 100;private Uri fileUri;

@Overridepublic void onCreate(Bundle savedInstanceState

) { super.onCreate(savedInstanceState);

setContentView(R.layout.main);

// create Intent to take a picture and return control to the calling application Intent intent = new

Intent(MediaStore.ACTION_IMAGE_CAPTURE);

fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE); // create a file to save the image intent.putExtra

(

MediaStore.

EXTRA_OUTPUT

,

fileUri

);

// set the image file name

// start the image capture Intent

startActivityForResult

(intent,

CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE

);

}

http://developer.android.com/guide/topics/media/camera.html

Slide31

Image Capture Intent

MediaStore.EXTRA_OUTPUT- This setting requires a Uri object specifying a path and file name where you'd like to save the picture. This setting is optional but strongly recommended. If you do not specify this value, the camera application saves the requested picture in the default location with a default name, specified in the returned intent's Intent.getData() field.

31private static final int

CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 100;private Uri fileUri;

@Overridepublic void onCreate(Bundle

savedInstanceState) { super.onCreate(savedInstanceState);

setContentView(R.layout.main);

// create Intent to take a picture and return control to the calling application Intent intent = new

Intent(MediaStore.ACTION_IMAGE_CAPTURE);

fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE); // create a file to save the image

intent.putExtra

(

MediaStore.

EXTRA_OUTPUT

,

fileUri

);

// set the image file name

// start the image capture Intent

startActivityForResult

(intent,

CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE

);

}

Slide32

@Override

protected void

onActivityResult(int

requestCode, int resultCode, Intent data) { if (

requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) { if (

resultCode == RESULT_OK) { // Image captured and saved to fileUri specified in the Intent

Bitmap thumbnail = data.getParcelableExtra("data"); Toast.makeText

(this, "Image saved to:\n" +

data.getData(), Toast.LENGTH_LONG).show(); } else if

(resultCode == RESULT_CANCELED) { // User cancelled the image capture

}

else

{

// Image capture failed, advise user

}

}

if

(

requestCode

==

CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE

) {

if

(

resultCode

==

RESULT_OK

) {

// Video captured and saved to

fileUri

specified in the Intent

Toast.

makeText

(

this

,

"Video saved to:

\n

"

+

data.getData

(),

Toast.

LENGTH_LONG

).show();

}

else if

(

resultCode

==

RESULT_CANCELED

) {

// User cancelled the video capture

}

else

{

// Video capture failed, advise user

}

}

}

Retrieve Results

32

Receive the

result with the file system

location of

the

new Image

Receive the result

with the file

system location of

the new Video.

Slide33

33

Slide34

Media RouterAs users connect their televisions, home

theatre systems and music players with wireless technologies, they want to be able to play content from Android apps on these larger, louder devices. Enabling this kind of playback can turn your one-device, one-user app into a shared experience that delights and inspires multiple users.

34

Slide35

35

https://www.youtube.com/watch?v=_NGB10uN6OI

Media Router

Slide36

Recommended Reading

Android Developer Site: Media and Camerahttp://developer.android.com/guide/topics/media/index.htmlVogella Tutorial: Handling Media with Androidhttp://

www.vogella.com/tutorials/AndroidMedia/article.html36