Android_多媒体详解

Android_多媒体详解

①播放音频

在Android中播放音频文件一般是使用MediaPlayer类来实现的。MediaPlayer包含以下控制方法：
1、setDataSource()：设置要播放的音频文件的位置
2、prepare()：播放之前完成准备工作
3、start()：开始或继续播放
4、pause()：暂停播放
5、reset()：重置
6、seekTo()：从指定位置位置开始播放
7、stop()：停止
8、release()：释放相关资源
9、isPlaying()：是否正在播放
10、getDuration()：获取音频文件长度

实例：

public class MainActivity extends Activity implements OnClickListener {
	private Button play;
	private Button pause;
	private Button stop;
	private MediaPlayer mediaPlayer = new MediaPlayer();

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		play = (Button) findViewById(R.id.play);
		pause = (Button) findViewById(R.id.pause);
		stop = (Button) findViewById(R.id.stop);
		play.setOnClickListener(this);
		pause.setOnClickListener(this);
		stop.setOnClickListener(this);
		initMediaPlayer();
	}

	private void initMediaPlayer() {
		try {
			File file = new File(Environment.getExternalStorageDirectory(),"music.mp3");
			mediaPlayer.setDataSource(file.getPath());
			mediaPlayer.prepare();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.play:
			if (!mediaPlayer.isPlaying()) {
				mediaPlayer.start();
			}
			break;
		case R.id.pause:
			if (mediaPlayer.isPlaying()) {
				mediaPlayer.pause();
			}
			break;
		case R.id.stop:
			if (mediaPlayer.isPlaying()) {
				mediaPlayer.reset();
				initMediaPlayer();
			}
			break;
		default:
			break;
		}
	}

	@Override
	protected void onDestroy() {
		super.onDestroy();
		if (mediaPlayer != null) {
			mediaPlayer.stop();
			mediaPlayer.release();
		}
	}

}

②播放视频

播放视频主要使用VideoView类来实现。常用方法：
1、setVideoPath()：设置播放文件位置
2、start()：开始
3、pause()：暂停
4、resume()：重新开始
5、seekTo()：从指定位置开始
6、isPlaying()：是否正在播放
7、getDuration()：载入长度

实例：

public class MainActivity extends Activity implements OnClickListener {
	private VideoView videoView;
	private Button play;
	private Button pause;
	private Button replay;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		play = (Button) findViewById(R.id.play);
		pause = (Button) findViewById(R.id.pause);
		replay = (Button) findViewById(R.id.replay);
		videoView = (VideoView) findViewById(R.id.video_view);
		play.setOnClickListener(this);
		pause.setOnClickListener(this);
		replay.setOnClickListener(this);
		initVideoPath();
	}

	private void initVideoPath() {
		File file = new File(Environment.getExternalStorageDirectory(), "movie.3gp");
		videoView.setVideoPath(file.getPath());
	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.play:
			if (!videoView.isPlaying()) {
				videoView.start();
			}
			break;
		case R.id.pause:
			if (videoView.isPlaying()) {
				videoView.pause();
			}
			break;
		case R.id.replay:
			if (videoView.isPlaying()) {
				videoView.resume();
			}
			break;
		}
	}

	@Override
	protected void onDestroy() {
		super.onDestroy();
		if (videoView != null) {
			videoView.suspend();
		}
	}
}

③调用摄像头和相册

public class MainActivity extends Activity {
	public static final int TAKE_PHOTO = 1;
	public static final int CROP_PHOTO = 2;
	private Button takePhoto;
	private Button chooseFromAlbum;
	private ImageView picture;
	private Uri imageUri;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		takePhoto = (Button) findViewById(R.id.take_photo);
		chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);
		picture = (ImageView) findViewById(R.id.picture);
		takePhoto.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				File outputImage = new File(Environment.getExternalStorageDirectory(),
						"output_image.jpg");
				try {
					if (outputImage.exists()) {
						outputImage.delete();
					}
					outputImage.createNewFile();
				} catch (IOException e) {
					e.printStackTrace();
				}
				imageUri = Uri.fromFile(outputImage);
				Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
				intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
				startActivityForResult(intent, TAKE_PHOTO);
			}
		});
		chooseFromAlbum.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				File outputImage = new File(Environment.getExternalStorageDirectory(),
						"output_image.jpg");
				try {
					if (outputImage.exists()) {
						outputImage.delete();
					}
					outputImage.createNewFile();
				} catch (IOException e) {
					e.printStackTrace();
				}
				imageUri = Uri.fromFile(outputImage);
				Intent intent = new Intent("android.intent.action.GET_CONTENT");
				intent.setType("image/*");
				intent.putExtra("crop", true);
				intent.putExtra("scale", true);
				intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
				startActivityForResult(intent, CROP_PHOTO);
			}
		});
	}

	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		switch (requestCode) {
		case TAKE_PHOTO:
			if (resultCode == RESULT_OK) {
				Intent intent = new Intent("com.android.camera.action.CROP");
				intent.setDataAndType(imageUri, "image/*");
				intent.putExtra("scale", true);
				intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
				startActivityForResult(intent, CROP_PHOTO);
			}
			break;
		case CROP_PHOTO:
			if (resultCode == RESULT_OK) {
				try {
					Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver()
							.openInputStream(imageUri));
					picture.setImageBitmap(bitmap);
				} catch (FileNotFoundException e) {
					e.printStackTrace();
				}
			}
			break;
		default:
			break;
		}
	}

}

④使用通知

public class MainActivity extends Activity implements OnClickListener {

	private Button sendNotice;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		sendNotice = (Button) findViewById(R.id.send_notice);
		sendNotice.setOnClickListener(this);
	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.send_notice:
			NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
			Notification notification = new Notification(
					R.drawable.ic_launcher, "This is ticker text",
					System.currentTimeMillis());
			Uri soundUri = Uri.fromFile(new File("/system/media/audio/ringtones/Basic_tone.ogg"));
			notification.sound = soundUri;
			long[] vibrates = {0, 1000, 1000, 1000};
			notification.vibrate = vibrates;
			notification.ledARGB = Color.GREEN;
			notification.ledOnMS = 1000;
			notification.ledOffMS = 1000;
			notification.flags = Notification.FLAG_SHOW_LIGHTS;
//			notification.defaults = Notification.DEFAULT_ALL;
			Intent intent = new Intent(this, NotificationActivity.class);
			PendingIntent pi = PendingIntent.getActivity(this, 0, intent,
					PendingIntent.FLAG_CANCEL_CURRENT);
			notification.setLatestEventInfo(this, "This is content title",
					"This is content text", pi);
			manager.notify(1, notification);
			break;
		default:
			break;
		}
	}

}