//
//src\com\example\android\musicplayer\AudioFocusHelper.java
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.musicplayer;
import android.content.Context;
import android.media.AudioManager;
/**
* Convenience class to deal with audio focus. This class deals with everything related to audio
* focus: it can request and abandon focus, and will intercept focus change events and deliver
* them to a MusicFocusable interface (which, in our case, is implemented by {@link MusicService}).
*
* This class can only be used on SDK level 8 and above, since it uses API features that are not
* available on previous SDK's.
*/
public class AudioFocusHelper implements AudioManager.OnAudioFocusChangeListener {
AudioManager mAM;
MusicFocusable mFocusable;
public AudioFocusHelper(Context ctx, MusicFocusable focusable) {
mAM = (AudioManager) ctx.getSystemService(Context.AUDIO_SERVICE);
mFocusable = focusable;
}
/** Requests audio focus. Returns whether request was successful or not. */
public boolean requestFocus() {
return AudioManager.AUDIOFOCUS_REQUEST_GRANTED ==
mAM.requestAudioFocus(this, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN);
}
/** Abandons audio focus. Returns whether request was successful or not. */
public boolean abandonFocus() {
return AudioManager.AUDIOFOCUS_REQUEST_GRANTED == mAM.abandonAudioFocus(this);
}
/**
* Called by AudioManager on audio focus changes. We implement this by calling our
* MusicFocusable appropriately to relay the message.
*/
@Override
public void onAudioFocusChange(int focusChange) {
if (mFocusable == null) return;
switch (focusChange) {
case AudioManager.AUDIOFOCUS_GAIN:
mFocusable.onGainedAudioFocus();
break;
case AudioManager.AUDIOFOCUS_LOSS:
case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
mFocusable.onLostAudioFocus(false);
break;
case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
mFocusable.onLostAudioFocus(true);
break;
default:
}
}
}
//src\com\example\android\musicplayer\MainActivity.java
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.musicplayer;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
/**
* Main activity: shows media player buttons. This activity shows the media player buttons and
* lets the user click them. No media handling is done here -- everything is done by passing
* Intents to our {@link MusicService}.
* */
public class MainActivity extends Activity implements OnClickListener {
/**
* The URL we suggest as default when adding by URL. This is just so that the user doesn't
* have to find an URL to test this sample.
*/
final String SUGGESTED_URL = "http://www.vorbis.com/music/Epoq-Lepidoptera.ogg";
Button mPlayButton;
Button mPauseButton;
Button mSkipButton;
Button mRewindButton;
Button mStopButton;
Button mEjectButton;
/**
* Called when the activity is first created. Here, we simply set the event listeners and
* start the background service ({@link MusicService}) that will handle the actual media
* playback.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mPlayButton = (Button) findViewById(R.id.playbutton);
mPauseButton = (Button) findViewById(R.id.pausebutton);
mSkipButton = (Button) findViewById(R.id.skipbutton);
mRewindButton = (Button) findViewById(R.id.rewindbutton);
mStopButton = (Button) findViewById(R.id.stopbutton);
mEjectButton = (Button) findViewById(R.id.ejectbutton);
mPlayButton.setOnClickListener(this);
mPauseButton.setOnClickListener(this);
mSkipButton.setOnClickListener(this);
mRewindButton.setOnClickListener(this);
mStopButton.setOnClickListener(this);
mEjectButton.setOnClickListener(this);
}
@Override
public void onClick(View target) {
// Send the correct intent to the MusicService, according to the button that was clicked
if (target == mPlayButton)
startService(new Intent(MusicService.ACTION_PLAY));
else if (target == mPauseButton)
startService(new Intent(MusicService.ACTION_PAUSE));
else if (target == mSkipButton)
startService(new Intent(MusicService.ACTION_SKIP));
else if (target == mRewindButton)
startService(new Intent(MusicService.ACTION_REWIND));
else if (target == mStopButton)
startService(new Intent(MusicService.ACTION_STOP));
else if (target == mEjectButton) {
showUrlDialog();
}
}
/**
* Shows an alert dialog where the user can input a URL. After showing the dialog, if the user
* confirms, sends the appropriate intent to the {@link MusicService} to cause that URL to be
* played.
*/
void showUrlDialog() {
AlertDialog.Builder alertBuilder = new AlertDialog.Builder(this);
alertBuilder.setTitle("Manual Input");
alertBuilder.setMessage("Enter a URL (must be http://)");
final EditText input = new EditText(this);
alertBuilder.setView(input);
input.setText(SUGGESTED_URL);
alertBuilder.setPositiveButton("Play!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dlg, int whichButton) {
// Send an intent with the URL of the song to play. This is expected by
// MusicService.
Intent i = new Intent(MusicService.ACTION_URL);
Uri uri = Uri.parse(input.getText().toString());
i.setData(uri);
startService(i);
}
});
alertBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dlg, int whichButton) {}
});
alertBuilder.show();
}
}
//src\com\example\android\musicplayer\MusicFocusable.java
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.musicplayer;
/**
* Represents something that can react to audio focus events. We implement this instead of just
* using AudioManager.OnAudioFocusChangeListener because that interface is only available in SDK
* level 8 and above, and we want our application to work on previous SDKs.
*/
public interface MusicFocusable {
/** Signals that audio focus was gained. */
public void onGainedAudioFocus();
/**
* Signals that audio focus was lost.
*
* @param canDuck If true, audio can continue in "ducked" mode (low volume). Otherwise, all
* audio must stop.
*/
public void onLostAudioFocus(boolean canDuck);
}
//src\com\example\android\musicplayer\MusicIntentReceiver.java
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.musicplayer;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;
/**
* Receives broadcasted intents. In particular, we are interested in the
* android.media.AUDIO_BECOMING_NOISY intent, which is broadcast, for example, when the user
* disconnects the headphones. This class works because we are declaring it in a <receiver>
* tag in AndroidManifest.xml.
*/
public class MusicIntentReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context ctx, Intent intent) {
if (intent.getAction().equals(android.media.AudioManager.ACTION_AUDIO_BECOMING_NOISY)) {
Toast.makeText(ctx, "Headphones disconnected.", Toast.LENGTH_SHORT).show();
// send an intent to our MusicService to telling it to pause the audio
ctx.startService(new Intent(MusicService.ACTION_PAUSE));
}
}
}
//src\com\example\android\musicplayer\MusicRetriever.java
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.musicplayer;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.database.Cursor;
import android.net.Uri;
import android.util.Log;
/**
* Retrieves and organizes media to play. Before being used, you must call {@link #prepare()},
* which will retrieve all of the music on the user's device (by performing a query on a content
* resolver). After that, it's ready to retrieve a random song, with its title and URI, upon
* request.
*/
public class MusicRetriever {
final String TAG = "MusicRetriever";
ContentResolver mContentResolver;
// the items (songs) we have queried
List- mItems = new ArrayList
- ();
Random mRandom = new Random();
public MusicRetriever(ContentResolver cr) {
mContentResolver = cr;
}
/**
* Loads music data. This method may take long, so be sure to call it asynchronously without
* blocking the main thread.
*/
public void prepare() {
Uri uri = android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
Log.i(TAG, "Querying media...");
Log.i(TAG, "URI: " + uri.toString());
// Perform a query on the content resolver. The URI we're passing specifies that we
// want to query for all audio media on external storage (e.g. SD card)
Cursor cur = mContentResolver.query(uri, null, null, null, null);
Log.i(TAG, "Query finished. " + (cur == null ? "Returned NULL." : "Returned a cursor."));
if (cur == null) {
// Query failed...
Log.e(TAG, "Failed to retrieve music: cursor is null :-(");
return;
}
if (!cur.moveToFirst()) {
// Nothing to query. There is no music on the device. How boring.
Log.e(TAG, "Failed to move cursor to first row (no query results).");
return;
}
Log.i(TAG, "Listing...");
// retrieve the indices of the columns where the ID and title of the song are
int titleColumn = cur.getColumnIndex(android.provider.MediaStore.Audio.Media.TITLE);
int idColumn = cur.getColumnIndex(android.provider.MediaStore.Audio.Media._ID);
Log.i(TAG, "Title column index: " + String.valueOf(titleColumn));
Log.i(TAG, "ID column index: " + String.valueOf(titleColumn));
// add each song to mItems
do {
Log.i(TAG, "ID: " + cur.getString(idColumn) + " Title: " + cur.getString(titleColumn));
mItems.add(new Item(cur.getLong(idColumn), cur.getString(titleColumn)));
} while (cur.moveToNext());
Log.i(TAG, "Done querying media. MusicRetriever is ready.");
}
public ContentResolver getContentResolver() {
return mContentResolver;
}
/** Returns a random Item. If there are no items available, returns null. */
public Item getRandomItem() {
if (mItems.size() <= 0) return null;
return mItems.get(mRandom.nextInt(mItems.size()));
}
public class Item {
long id;
String title;
public Item(long id, String title) {
this.id = id;
this.title = title;
}
public long getId() { return id; }
public String getTitle() { return title; }
public Uri getURI() {
return ContentUris.withAppendedId(
android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, id);
}
}
}
//src\com\example\android\musicplayer\MusicService.java
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.musicplayer;
import java.io.IOException;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnErrorListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.net.Uri;
import android.net.wifi.WifiManager;
import android.net.wifi.WifiManager.WifiLock;
import android.os.IBinder;
import android.os.PowerManager;
import android.util.Log;
import android.widget.Toast;
/**
* Service that handles media playback. This is the Service through which we perform all the media
* handling in our application. Upon initialization, it starts a {@link MediaRetriever} to scan
* the user's media. Then, it waits for Intents (which come from our main activity,
* {@link MainActivity}, which signal the service to perform specific operations: Play, Pause,
* Rewind, Skip, etc.
*/
public class MusicService extends Service implements OnCompletionListener, OnPreparedListener,
OnErrorListener, MusicFocusable,
PrepareMusicRetrieverTask.MusicRetrieverPreparedListener {
NotificationManager mNotificationManager;
// our media player
MediaPlayer mPlayer = null;
// our AudioFocusHelper object, if it's available (it's available on SDK level >= 8)
// If not available, this will be null. Always check for null before using!
AudioFocusHelper mAudioFocusHelper = null;
// indicates the state our service:
enum State {
Retrieving, // the MediaRetriever is retrieving music
Stopped, // media player is stopped and not prepared to play
Preparing, // media player is preparing...
Playing, // playback active (media player ready!). (but the media player may actually be
// paused in this state if we don't have audio focus. But we stay in this state
// so that we know we have to resume playback once we get focus back)
Paused // playback paused (media player ready!)
};
State mState = State.Retrieving;
// if in Retrieving mode, this flag indicates whether we should start playing immediately
// when we are ready or not.
boolean mStartPlayingAfterRetrieve = false;
// if mStartPlayingAfterRetrieve is true, this variable indicates the URL that we should
// start playing when we are ready. If null, we should play a random song from the device
Uri mWhatToPlayAfterRetrieve = null;
enum PauseReason {
UserRequest, // paused by user request
FocusLoss, // paused because of audio focus loss
};
// why did we pause? (only relevant if mState == State.Paused)
PauseReason mPauseReason = PauseReason.UserRequest;
// do we have audio focus?
enum AudioFocus {
NoFocusNoDuck, // we don't have audio focus, and can't duck
NoFocusCanDuck, // we don't have focus, but can play at a low volume ("ducking")
Focused // we have full audio focus
}
AudioFocus mAudioFocus = AudioFocus.NoFocusNoDuck;
// title of the song we are currently playing
String mSongTitle = "";
// whether the song we are playing is streaming from the network
boolean mIsStreaming = false;
// Wifi lock that we hold when streaming files from the internet, in order to prevent the
// device from shutting off the Wifi radio
WifiLock mWifiLock;
// The tag we put on debug messages
final static String TAG = "RandomMusicPlayer";
// These are the Intent actions that we are prepared to handle. Notice that the fact these
// constants exist in our class is a mere convenience: what really defines the actions our
// service can handle are the tags in the tag for our service in
// AndroidManifest.xml.
public static final String ACTION_PLAY = "com.example.android.musicplayer.action.PLAY";
public static final String ACTION_PAUSE = "com.example.android.musicplayer.action.PAUSE";
public static final String ACTION_STOP = "com.example.android.musicplayer.action.STOP";
public static final String ACTION_SKIP = "com.example.android.musicplayer.action.SKIP";
public static final String ACTION_REWIND = "com.example.android.musicplayer.action.REWIND";
public static final String ACTION_URL = "com.example.android.musicplayer.action.URL";
// The volume we set the media player to when we lose audio focus, but are allowed to reduce
// the volume instead of stopping playback.
public final float DUCK_VOLUME = 0.1f;
// The ID we use for the notification (the onscreen alert that appears at the notification
// area at the top of the screen as an icon -- and as text as well if the user expands the
// notification area).
final int NOTIFICATION_ID = 1;
// Our instance of our MusicRetriever, which handles scanning for media and
// providing titles and URIs as we need.
MusicRetriever mRetriever;
Notification mNotification = null;
/**
* Makes sure the media player exists and has been reset. This will create the media player
* if needed, or reset the existing media player if one already exists.
*/
void createMediaPlayerIfNeeded() {
if (mPlayer == null) {
mPlayer = new MediaPlayer();
// Make sure the media player will acquire a wake-lock while playing. If we don't do
// that, the CPU might go to sleep while the song is playing, causing playback to stop.
//
// Remember that to use this, we have to declare the android.permission.WAKE_LOCK
// permission in AndroidManifest.xml.
mPlayer.setWakeMode(getApplicationContext(), PowerManager.PARTIAL_WAKE_LOCK);
// we want the media player to notify us when it's ready preparing, and when it's done
// playing:
mPlayer.setOnPreparedListener(this);
mPlayer.setOnCompletionListener(this);
mPlayer.setOnErrorListener(this);
}
else
mPlayer.reset();
}
@Override
public void onCreate() {
Log.i(TAG, "debug: Creating service");
// Create the Wifi lock (this does not acquire the lock, this just creates it)
mWifiLock = ((WifiManager) getSystemService(Context.WIFI_SERVICE))
.createWifiLock(WifiManager.WIFI_MODE_FULL, "mylock");
mNotificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
// Create the retriever and start an asynchronous task that will prepare it.
mRetriever = new MusicRetriever(getContentResolver());
(new PrepareMusicRetrieverTask(mRetriever,this)).execute();
// create the Audio Focus Helper, if the Audio Focus feature is available (SDK 8 or above)
if (android.os.Build.VERSION.SDK_INT >= 8)
mAudioFocusHelper = new AudioFocusHelper(getApplicationContext(), this);
else
mAudioFocus = AudioFocus.Focused; // no focus feature, so we always "have" audio focus
}
/**
* Called when we receive an Intent. When we receive an intent sent to us via startService(),
* this is the method that gets called. So here we react appropriately depending on the
* Intent's action, which specifies what is being requested of us.
*/
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
String action = intent.getAction();
if (action.equals(ACTION_PLAY)) processPlayRequest();
else if (action.equals(ACTION_PAUSE)) processPauseRequest();
else if (action.equals(ACTION_SKIP)) processSkipRequest();
else if (action.equals(ACTION_STOP)) processStopRequest();
else if (action.equals(ACTION_REWIND)) processRewindRequest();
else if (action.equals(ACTION_URL)) processAddRequest(intent);
return START_NOT_STICKY; // Means we started the service, but don't want it to
// restart in case it's killed.
}
void processPlayRequest() {
if (mState == State.Retrieving) {
// If we are still retrieving media, just set the flag to start playing when we're
// ready
mWhatToPlayAfterRetrieve = null; // play a random song
mStartPlayingAfterRetrieve = true;
return;
}
tryToGetAudioFocus();
if (mState == State.Stopped) {
// If we're stopped, just go ahead to the next song and start playing
playNextSong(null);
}
else if (mState == State.Paused) {
// If we're paused, just continue playback and restore the 'foreground service' state.
mState = State.Playing;
setUpAsForeground(mSongTitle + " (playing)");
configAndStartMediaPlayer();
}
}
void processPauseRequest() {
if (mState == State.Retrieving) {
// If we are still retrieving media, clear the flag that indicates we should start
// playing when we're ready
mStartPlayingAfterRetrieve = false;
return;
}
if (mState == State.Playing) {
// Pause media player and cancel the 'foreground service' state.
mState = State.Paused;
mPlayer.pause();
relaxResources(false); // while paused, we always retain the MediaPlayer
giveUpAudioFocus();
}
}
void processRewindRequest() {
if (mState == State.Playing || mState == State.Paused)
mPlayer.seekTo(0);
}
void processSkipRequest() {
if (mState == State.Playing || mState == State.Paused) {
tryToGetAudioFocus();
playNextSong(null);
}
}
void processStopRequest() {
if (mState == State.Playing || mState == State.Paused) {
mState = State.Stopped;
// let go of all resources...
relaxResources(true);
giveUpAudioFocus();
// service is no longer necessary. Will be started again if needed.
stopSelf();
}
}
/**
* Releases resources used by the service for playback. This includes the "foreground service"
* status and notification, the wake locks and possibly the MediaPlayer.
*
* @param releaseMediaPlayer Indicates whether the Media Player should also be released or not
*/
void relaxResources(boolean releaseMediaPlayer) {
// stop being a foreground service
stopForeground(true);
// stop and release the Media Player, if it's available
if (releaseMediaPlayer && mPlayer != null) {
mPlayer.reset();
mPlayer.release();
mPlayer = null;
}
// we can also release the Wifi lock, if we're holding it
if (mWifiLock.isHeld()) mWifiLock.release();
}
void giveUpAudioFocus() {
if (mAudioFocus == AudioFocus.Focused && mAudioFocusHelper != null
&& mAudioFocusHelper.abandonFocus())
mAudioFocus = AudioFocus.NoFocusNoDuck;
}
/**
* Reconfigures MediaPlayer according to audio focus settings and starts/restarts it. This
* method starts/restarts the MediaPlayer respecting the current audio focus state. So if
* we have focus, it will play normally; if we don't have focus, it will either leave the
* MediaPlayer paused or set it to a low volume, depending on what is allowed by the
* current focus settings. This method assumes mPlayer != null, so if you are calling it,
* you have to do so from a context where you are sure this is the case.
*/
void configAndStartMediaPlayer() {
if (mAudioFocus == AudioFocus.NoFocusNoDuck) {
// If we don't have audio focus and can't duck, we have to pause, even if mState
// is State.Playing. But we stay in the Playing state so that we know we have to resume
// playback once we get the focus back.
if (mPlayer.isPlaying()) mPlayer.pause();
return;
}
else if (mAudioFocus == AudioFocus.NoFocusCanDuck)
mPlayer.setVolume(DUCK_VOLUME, DUCK_VOLUME); // we'll be relatively quiet
else
mPlayer.setVolume(1.0f, 1.0f); // we can be loud
if (!mPlayer.isPlaying()) mPlayer.start();
}
void processAddRequest(Intent intent) {
// user wants to play a song directly by URL or path. The URL or path comes in the "data"
// part of the Intent. This Intent is sent by {@link MainActivity} after the user
// specifies the URL/path via an alert box.
if (mState == State.Retrieving) {
// we'll play the requested URL right after we finish retrieving
mWhatToPlayAfterRetrieve = intent.getData();
mStartPlayingAfterRetrieve = true;
}
else if (mState == State.Playing || mState == State.Paused || mState == State.Stopped) {
Log.i(TAG, "Playing from URL/path: " + intent.getData().toString());
tryToGetAudioFocus();
playNextSong(intent.getData().toString());
}
}
/**
* Shortcut to making and displaying a toast. Seemed cleaner than repeating
* this code everywhere, at least for this sample.
*/
void say(String message) {
Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}
void tryToGetAudioFocus() {
if (mAudioFocus != AudioFocus.Focused && mAudioFocusHelper != null
&& mAudioFocusHelper.requestFocus())
mAudioFocus = AudioFocus.Focused;
}
/**
* Starts playing the next song. If manualUrl is null, the next song will be randomly selected
* from our Media Retriever (that is, it will be a random song in the user's device). If
* manualUrl is non-null, then it specifies the URL or path to the song that will be played
* next.
*/
void playNextSong(String manualUrl) {
mState = State.Stopped;
relaxResources(false); // release everything except MediaPlayer
try {
if (manualUrl != null) {
// set the source of the media player to a manual URL or path
createMediaPlayerIfNeeded();
mPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
mPlayer.setDataSource(manualUrl);
mSongTitle = manualUrl;
mIsStreaming = manualUrl.startsWith("http:") || manualUrl.startsWith("https:");
}
else {
mIsStreaming = false; // playing a locally available song
MusicRetriever.Item item = mRetriever.getRandomItem();
if (item == null) {
say("No song to play :-(");
return;
}
// set the source of the media player a a content URI
createMediaPlayerIfNeeded();
mPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
mPlayer.setDataSource(getApplicationContext(), item.getURI());
mSongTitle = item.getTitle();
}
mState = State.Preparing;
setUpAsForeground(mSongTitle + " (loading)");
// starts preparing the media player in the background. When it's done, it will call
// our OnPreparedListener (that is, the onPrepared() method on this class, since we set
// the listener to 'this').
//
// Until the media player is prepared, we *cannot* call start() on it!
mPlayer.prepareAsync();
// If we are streaming from the internet, we want to hold a Wifi lock, which prevents
// the Wifi radio from going to sleep while the song is playing. If, on the other hand,
// we are *not* streaming, we want to release the lock if we were holding it before.
if (mIsStreaming) mWifiLock.acquire();
else if (mWifiLock.isHeld()) mWifiLock.release();
}
catch (IOException ex) {
Log.e("MusicService", "IOException playing next song: " + ex.getMessage());
ex.printStackTrace();
}
}
/** Called when media player is done playing current song. */
@Override
public void onCompletion(MediaPlayer player) {
// The media player finished playing the current song, so we go ahead and start the next.
playNextSong(null);
}
/** Called when media player is done preparing. */
@Override
public void onPrepared(MediaPlayer player) {
// The media player is done preparing. That means we can start playing!
mState = State.Playing;
updateNotification(mSongTitle + " (playing)");
configAndStartMediaPlayer();
}
/** Updates the notification. */
void updateNotification(String text) {
PendingIntent pi = PendingIntent.getActivity(getApplicationContext(), 0,
new Intent(getApplicationContext(), MainActivity.class),
PendingIntent.FLAG_UPDATE_CURRENT);
mNotification.setLatestEventInfo(getApplicationContext(), "RandomMusicPlayer", text, pi);
mNotificationManager.notify(NOTIFICATION_ID, mNotification);
}
/**
* Configures service as a foreground service. A foreground service is a service that's doing
* something the user is actively aware of (such as playing music), and must appear to the
* user as a notification. That's why we create the notification here.
*/
void setUpAsForeground(String text) {
PendingIntent pi = PendingIntent.getActivity(getApplicationContext(), 0,
new Intent(getApplicationContext(), MainActivity.class),
PendingIntent.FLAG_UPDATE_CURRENT);
mNotification = new Notification();
mNotification.tickerText = text;
mNotification.icon = R.drawable.ic_stat_playing;
mNotification.flags |= Notification.FLAG_ONGOING_EVENT;
mNotification.setLatestEventInfo(getApplicationContext(), "RandomMusicPlayer",
text, pi);
startForeground(NOTIFICATION_ID, mNotification);
}
/**
* Called when there's an error playing media. When this happens, the media player goes to
* the Error state. We warn the user about the error and reset the media player.
*/
@Override
public boolean onError(MediaPlayer mp, int what, int extra) {
Toast.makeText(getApplicationContext(), "Media player error! Resetting.",
Toast.LENGTH_SHORT).show();
Log.e(TAG, "Error: what=" + String.valueOf(what) + ", extra=" + String.valueOf(extra));
mState = State.Stopped;
relaxResources(true);
giveUpAudioFocus();
return true; // true indicates we handled the error
}
@Override
public void onGainedAudioFocus() {
Toast.makeText(getApplicationContext(), "gained audio focus.", Toast.LENGTH_SHORT).show();
mAudioFocus = AudioFocus.Focused;
// restart media player with new focus settings
if (mState == State.Playing)
configAndStartMediaPlayer();
}
@Override
public void onLostAudioFocus(boolean canDuck) {
Toast.makeText(getApplicationContext(), "lost audio focus." + (canDuck ? "can duck" :
"no duck"), Toast.LENGTH_SHORT).show();
mAudioFocus = canDuck ? AudioFocus.NoFocusCanDuck : AudioFocus.NoFocusNoDuck;
// start/restart/pause media player with new focus settings
if (mPlayer != null && mPlayer.isPlaying())
configAndStartMediaPlayer();
}
@Override
public void onMusicRetrieverPrepared() {
// Done retrieving!
mState = State.Stopped;
// If the flag indicates we should start playing after retrieving, let's do that now.
if (mStartPlayingAfterRetrieve) {
tryToGetAudioFocus();
playNextSong(mWhatToPlayAfterRetrieve == null ?
null : mWhatToPlayAfterRetrieve.toString());
}
}
@Override
public void onDestroy() {
// Service is being killed, so make sure we release our resources
mState = State.Stopped;
relaxResources(true);
giveUpAudioFocus();
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
}
//src\com\example\android\musicplayer\PrepareMusicRetrieverTask.java
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.musicplayer;
import android.os.AsyncTask;
/**
* Asynchronous task that prepares a MusicRetriever. This asynchronous task essentially calls
* {@link MusicRetriever#prepare()} on a {@link MusicRetriever}, which may take some time to
* run. Upon finishing, it notifies the indicated {@MusicRetrieverPreparedListener}.
*/
public class PrepareMusicRetrieverTask extends AsyncTask {
MusicRetriever mRetriever;
MusicRetrieverPreparedListener mListener;
public PrepareMusicRetrieverTask(MusicRetriever retriever,
MusicRetrieverPreparedListener listener) {
mRetriever = retriever;
mListener = listener;
}
@Override
protected Void doInBackground(Void... arg0) {
mRetriever.prepare();
return null;
}
@Override
protected void onPostExecute(Void result) {
mListener.onMusicRetrieverPrepared();
}
public interface MusicRetrieverPreparedListener {
public void onMusicRetrieverPrepared();
}
}
//
//res\layout-land\main.xml
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:background="#000040"
>
android:layout_height="wrap_content"
android:padding="20dp"
android:textColor="#ffffff"
android:textSize="20sp"
android:textStyle="bold"
/>
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
>
android:background="@drawable/selector_rew"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
android:background="@drawable/selector_play"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
android:background="@drawable/selector_pause"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
android:background="@drawable/selector_ff"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
android:background="@drawable/selector_stop"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
android:background="@drawable/selector_eject"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
//
//res\layout-port\main.xml
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:background="#000040"
>
android:layout_height="wrap_content"
android:padding="20dp"
android:textColor="#ffffff"
android:textSize="20sp"
android:textStyle="bold"
/>
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_margin="10dp"
>
android:background="@drawable/selector_rew"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
android:background="@drawable/selector_play"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
android:background="@drawable/selector_pause"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
android:background="@drawable/selector_ff"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_margin="10dp"
>
android:background="@drawable/selector_stop"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>
android:background="@drawable/selector_eject"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_margin="5dp"
/>