Terms: MediaPlayer, VideoView, MediaController,

Transcription

1 Terms: MediaPlayer, VideoView, MediaController, Sisoft Technologies Pvt Ltd SRC E7, Shipra Riviera Bazar, Gyan Khand-3, Indirapuram, Ghaziabad Website: Phone:

2 MediaPlayer The playback of audio and video in Android is handled mostly by the MediaPlayer class To play a media resource you need to create a new MediaPlayer instance, initialize it with a media source, and prepare it for playback For playing media may be stored in application resources, local files, Content Providers, or streamed from a network URL In each case, the file format and type of multimedia being played is provided 2

3 Playback Audio To play back audio content using Media Player, a Media Player object should be created Media Player object may be created using create method: This requires application context and audio source location Using default constructor: After constructor, use setdatasource method to provide audio source location and call prepare method to prepare for playback 3

4 MediaPlayer.Create : Examples An application resource identifier (stored in res/raw folder) MediaPlayer resourceplayer = MediaPlayer.create(this, R.raw.my_audio); A URI to a local file using the file:// schema MediaPlayer fileplayer = MediaPlayer.create(this, Uri.parse( file:///sdcard/localfile.mp3 )); A URI to an online audio resource as a URL MediaPlayer urlplayer = MediaPlayer.create(this, Uri.parse( )); A URI to a local Content Provider row MediaPlayer contentplayer = MediaPlayer.create(this, Settings.System.DEFAULT_RINGTONE_URI); 4

5 MediaPlayer: Using Constructor MediaPlayer mediaplayer = new MediaPlayer(); mediaplayer.setdatasource("/sdcard/test.3gp"); mediaplayer.prepare(); For starting the Audio use MediaPlayer.start method Use MediaController.MediaPlayerControl to show the 5

6 Audio Files in Application Package Put your mp3 or video data in raw folder A audio files can be included in application package by adding them to the res/raw folder of resources hierarchy. File name should be in small letters Eg-abc.mp3,or abs.3gp 6

7 Playback Audio : Demo For Stop For Pause For Play 7

8 Playback Video To show a video, you must specify a display surface on which to show it. There are two alternatives for the playback of video content. The first, using the Video View control, encapsulates the creation of a display surface and allocation and preparation of video content within a Media Player. The second technique allows you to specify your own display surface and manipulate the underlying Media Player instance directly. 8

9 Playback Video: Using Video View The simplest way to play back video is to use the VideoView control The Video View includes a Surface on which the video is displayed and encapsulates and manages a Media Player to manage the video playback. The Video View supports the playback of local or streaming video as supported by the Media Player component. 9

10 Playback Video: Using Video View.. Place Video Views control in UI, get a reference to it within your code To assign a video to play, call setvideopath or setvideouri to specify the path to a local file, or the URI of a Content Provider or remote video stream: streamingvideoview.setvideouri(" localvideoview.setvideopath("/sdcard/test2.3gp"); Media Controller can be used to control video play-back, simply by the Video View s setmediacontroller method: MediaController mediacontroller = new MediaController(this); videoview.setmediacontroller(mediacontroller); 10

11 Playback Video: Example VideoView videoview = (VideoView)findViewById(R.id.surface); videoview.setkeepscreenon(true); videoview.setvideopath("/sdcard/test2.3gp"); if (videoview.canseekforward()) videoview.seekto(videoview.getduration()/2); videoview.start(); [... do something... ] videoview.stopplayback(); // Attach a Media Controller MediaController mediacontroller = new MediaController(this); videoview.setmediacontroller(mediacontroller); 11

12 Playback Video: Using Video View Video View 12

13 Playback Video: Using Media Player.. Setting up a Surface for Video Playback- TheMedia Player requires a SurfaceHolder object for displaying video content, assigned using the setdisplay method. 13

14 Playback Video: Media Player <LinearLayout xmlns:android=" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <SurfaceView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center"> </SurfaceView> </LinearLayout> 14

15 Playback Video: Media Player Note that you must implement the SurfaceHolder.Callback interface. Surface Holders are created asynchronously, so you must wait until the surfacecreated handler has been fired before assigning the returned Surface Holder object to the Media Player. 15

16 Playback Video: Media Player Viodeo view on emulator 16

17 Playback Video: Media Player Playing Video 17

18 Record Video: Media Recorder Audio capture from the device is a bit more complicated than audio and video playback, but still fairly simple: Create a new instance of android.media.mediarecorder. Set the audio source using MediaRecorder.setAudioSource(). You will probably want to use 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. Calling MediaRecorder.release() is always recommended to free the resource immediately. 18

19 Android Camera API

20 Android Camera The Android framework supports capturing images and video through the Camera API or camera Intent. Here are the relevant classes: o 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 o SurfaceView: This class is used to present a live camera preview to the user o MediaRecorder: This class is used to record video from the camera o 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

21 Manifest Declarations(Permissions) Before starting development on your application with the Camera API, you should make sure your manifest has the appropriate declarations to allow use of camera hardware and other related features. o Camera Permission - Your application must request permission to use a device camera <uses-permission android:name="android.permission.camera" /> o Camera Features - Your application must also declare use of camera features, for example: <uses-feature android:name="android.hardware.camera" />

22 Manifest Declarations(Permissions) o Storage Permission - If your application saves images or videos to the device's external storage (SD Card), you must also specify this in the manifest. <uses-permission android:name="android.permission.write_external_storage /> o Audio Recording Permission - For recording audio with video capture, your application must request the audio capture permission. <uses-permission android:name="android.permission.record_audio /> o Location Permission - If your application tags images with GPS location information, you must request location permission: <uses-permission android:name="android.permission.access_fine_location />

23 Using Existing Camera Apps The procedure for invoking a camera intent follows these general steps: Compose a Camera Intent - Create an Intent that requests an image or video, using one of these intent types: MediaStore.ACTION_IMAGE_CAPTURE - Intent action type for requesting an image from an existing camera application. MediaStore.ACTION_VIDEO_CAPTURE - Intent action type for requesting a video from an existing camera application. Start the Camera Intent - Use the startactivityforresult() method to execute the camera intent. After you start the intent, the Camera application user interface appears on the device screen and the user can take a picture or video. Receive the Intent Result - Set up an onactivityresult() method in your application to receive the callback and data from the camera intent. When the user finishes taking a picture or video (or cancels the operation), the system calls this method.

24 Example 1. 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: 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.

25 Example 1. Image capture intent private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 100; private Uri public 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);

26 Example 2. Video capture intent Capturing video using a camera intent is a quick way to enable your application to take videos with minimal coding. A video capture intent can include the following extra information: MediaStore.EXTRA_OUTPUT - This setting requires a Uri specifying a path and file name where you'd like to save the video. This setting is optional but strongly recommended. If you do not specify this value, the Camera application saves the requested video in the default location with a default name, specified in the returned intent's Intent.getData() field. MediaStore.EXTRA_VIDEO_QUALITY- This value can be 0 for lowest quality and smallest file size or 1 for highest quality and larger file size. MediaStore.EXTRA_DURATION_LIMIT - Set this value to limit the length, in seconds, of the video being captured. MediaStore.EXTRA_SIZE_LIMIT - Set this value to limit the file size, in bytes, of the video being captured. The following example demonstrates how to construct a video capture intent and execute it. The getoutputmediafileuri() method in this example refers to the sample code shown in Saving Media Files.

27 Example :- Example 2. Video capture intent private static final int CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE = 200; private Uri public void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.main); Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE); //create new Intent fileuri = getoutputmediafileuri(media_type_video); // create a file to save the video intent.putextra(mediastore.extra_output, fileuri); // set the image file name intent.putextra(mediastore.extra_video_quality, 1); // set the video image quality to high } // start the Video Capture Intent startactivityforresult(intent, CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE);

28 Receiving camera intent result In order to receive the result of an intent, you must override the onactivityresult() in the activity that started the intent. The following example demonstrates how to override onactivityresult() to capture the result of the image camera intent or video camera intent examples shown in the previous sections. private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 100; private static final int CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE = 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 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 } }

29 Receiving camera intent result 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 } } } //onactivityresult Once your activity receives a successful result, the captured image or video is available in the specified location for your application to access

30 Detecting camera hardware If your application does not specifically require a camera using a manifest declaration, you should check to see if a camera is available at runtime. To perform this check, use the PackageManager.hasSystemFeature()method, as shown in the example code below: /** Check if this device has a camera */ private boolean checkcamerahardware(context context) { if (context.getpackagemanager().hassystemfeature(packagemanager.feature_camera)){ // this device has a camera return true; } else { // no camera on this device return false; } }

31 Accessing cameras o If you have determined that the device on which your application is running has a camera, you must request to access it by getting an instance of Camera (unless you are using an intent to access the camera) o To access the primary camera, use the Camera.open() method and be sure to catch any exceptions, as shown in the code below: /** A safe way to get an instance of the Camera object. */ public static Camera getcamerainstance(){ Camera c = null; try { c = Camera.open(); // attempt to get a Camera instance } catch (Exception e){ // Camera is not available (in use or does not exist) } return c; // returns null if camera is unavailable }

32 Checking camera features Once you obtain access to a camera, you can get further information about its capabilities using the Camera.getParameters() method and checking the returned Camera.Parameters object for supported capabilities. When using API Level 9 or higher, use the Camera.getCameraInfo() to determine if a camera is on the front or back of the device, and the orientation of the image.

33 Camera Features Android supports a wide array of camera features you can control with your camera application, such as picture format, flash mode, focus settings, and many more. This section lists the common camera features, and briefly discusses how to use them. Most camera features can be accessed and set using the through Camera. Parameters object. However, there are several important features that require more than simple settings in Camera. Parameters These features are covered in the following sections: Metering and focus areas Face detection Time lapse video