mediaplaybackservice.java

来自「Android平台上的media player, iPhone风格」· Java 代码 · 共 1,619 行 · 第 1/4 页

/*
 * Copyright (C) 2007 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.android.imusic;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.BroadcastReceiver;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.database.Cursor;
import android.media.AudioManager;
import android.media.MediaFile;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Environment;
import android.os.FileUtils;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.PowerManager;
import android.os.SystemClock;
import android.os.PowerManager.WakeLock;
import android.provider.MediaStore;
import android.provider.Settings;
//import com.android.internal.telephony.Phone;
//import com.android.internal.telephony.PhoneStateIntentReceiver;
import android.util.Log;
import android.widget.RemoteViews;
import android.widget.Toast;

import java.io.IOException;
import java.util.Random;
import java.util.Vector;

/**
 * Provides "background" audio playback capabilities, allowing the
 * user to switch between activities without stopping playback.
 */
public class MediaPlaybackService extends Service {
    /** used to specify whether enqueue() should start playing
     * the new list of files right away, next or once all the currently
     * queued files have been played
     */
    public static final int NOW = 1;
    public static final int NEXT = 2;
    public static final int LAST = 3;
    public static final int PLAYBACKSERVICE_STATUS = 1;
    
    public static final int SHUFFLE_NONE = 0;
    public static final int SHUFFLE_NORMAL = 1;
    public static final int SHUFFLE_AUTO = 2;
    
    public static final int REPEAT_NONE = 0;
    public static final int REPEAT_CURRENT = 1;
    public static final int REPEAT_ALL = 2;

    public static final String PLAYSTATE_CHANGED = "com.android.imusic.playstatechanged";
    public static final String META_CHANGED = "com.android.imusic.metachanged";
    public static final String QUEUE_CHANGED = "com.android.imusic.queuechanged";
    public static final String PLAYBACK_COMPLETE = "com.android.imusic.playbackcomplete";
    public static final String ASYNC_OPEN_COMPLETE = "com.android.imusic.asyncopencomplete";

    public static final String SERVICECMD = "com.android.imusic.musicservicecommand";
    public static final String CMDNAME = "command";
    public static final String CMDTOGGLEPAUSE = "togglepause";
    public static final String CMDPAUSE = "pause";
    public static final String CMDNEXT = "next";
    
    private static final int PHONE_CHANGED = 1;
    private static final int TRACK_ENDED = 1;
    private static final int RELEASE_WAKELOCK = 2;
    private static final int SERVER_DIED = 3;
    private static final int MAX_HISTORY_SIZE = 10;

    private MultiPlayer mPlayer;
    private String mFileToPlay;
//    private PhoneStateIntentReceiver mPsir;
    private int mShuffleMode = SHUFFLE_NONE;
    private int mRepeatMode = REPEAT_NONE;
    private int mMediaMountedCount = 0;
    private int [] mAutoShuffleList = null;
    private boolean mOneShot;
    private int [] mPlayList = null;
    private int mPlayListLen = 0;
    private Vector<Integer> mHistory = new Vector<Integer>(MAX_HISTORY_SIZE);
    private Cursor mCursor;
    private int mPlayPos = -1;
    private static final String LOGTAG = "MediaPlaybackService";
    private final Shuffler mRand = new Shuffler();
    private int mOpenFailedCounter = 0;
    String[] mCursorCols = new String[] {
            "audio._id AS _id",
            MediaStore.Audio.Media.ARTIST,
            MediaStore.Audio.Media.ALBUM,
            MediaStore.Audio.Media.TITLE,
            MediaStore.Audio.Media.DATA,
            MediaStore.Audio.Media.MIME_TYPE,
            MediaStore.Audio.Media.ALBUM_ID,
            MediaStore.Audio.Media.ARTIST_ID
    };
    private BroadcastReceiver mUnmountReceiver = null;
    private WakeLock mWakeLock;
    private int mServiceStartId = -1;
    private boolean mServiceInUse = false;
    private boolean mResumeAfterCall = false;
    private boolean mWasPlaying = false;
    
    private SharedPreferences mPreferences;
    // We use this to distinguish between different cards when saving/restoring playlists.
    // This will have to change if we want to support multiple simultaneous cards.
    private int mCardId;
    
    // interval after which we stop the service when idle
    private static final int IDLE_DELAY = 60000; 

    private Handler mPhoneHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case PHONE_CHANGED:
////                    Phone.State state = mPsir.getPhoneState();
////                    if (state == Phone.State.RINGING) {
//                        AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
//                        int ringvolume = audioManager.getStreamVolume(AudioManager.STREAM_RING);
//                        if (ringvolume > 0) {
//                            mResumeAfterCall = (isPlaying() || mResumeAfterCall) && (getAudioId() >= 0);
//                            pause();
//                        }
//                    } else if (state == Phone.State.OFFHOOK) {
//                        // pause the music while a conversation is in progress
//                        mResumeAfterCall = (isPlaying() || mResumeAfterCall) && (getAudioId() >= 0);
//                        pause();
//                    } else if (state == Phone.State.IDLE) {
//                        // start playing again
//                        if (mResumeAfterCall) {
//                            // resume playback only if music was playing
//                            // when the call was answered
//                            play();
//                            mResumeAfterCall = false;
//                        }
//                    }
                    break;
                default:
                    break;
            }
        }
    };

    private Handler mMediaplayerHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case SERVER_DIED:
                    if (mWasPlaying) {
                        next(true);
                    } else {
                        // the server died when we were idle, so just
                        // reopen the same song (it will start again
                        // from the beginning though when the user
                        // restarts)
                        openCurrent();
                    }
                    break;
                case TRACK_ENDED:
                    if (mRepeatMode == REPEAT_CURRENT) {
                        seek(0);
                        play();
                    } else if (!mOneShot) {
                        next(false);
                    } else {
                        notifyChange(PLAYBACK_COMPLETE);
                    }
                    break;
                case RELEASE_WAKELOCK:
                    mWakeLock.release();
                    break;
                default:
                    break;
            }
        }
    };

    private BroadcastReceiver mIntentReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String cmd = intent.getStringExtra("command");
            if (CMDNEXT.equals(cmd)) {
                next(true);
            } else if (CMDTOGGLEPAUSE.equals(cmd)) {
                if (isPlaying()) {
                    pause();
                } else {
                    play();
                }
            } else if (CMDPAUSE.equals(cmd)) {
                pause();
            }
        }
    };

    public MediaPlaybackService() {
//        mPsir = new PhoneStateIntentReceiver(this, mPhoneHandler);
//        mPsir.notifyPhoneCallState(PHONE_CHANGED);
    }

    @Override
    public void onCreate() {
        super.onCreate();
        
        mPreferences = getSharedPreferences("Music", MODE_WORLD_READABLE | MODE_WORLD_WRITEABLE);
        mCardId = FileUtils.getFatVolumeId(Environment.getExternalStorageDirectory().getPath());
        
        registerExternalStorageListener();

        // Needs to be done in this thread, since otherwise ApplicationContext.getPowerManager() crashes.
        mPlayer = new MultiPlayer();
        mPlayer.setHandler(mMediaplayerHandler);

        // Clear leftover notification in case this service previously got killed while playing
        NotificationManager nm = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        nm.cancel(PLAYBACKSERVICE_STATUS);
        
        reloadQueue();

        registerReceiver(mIntentReceiver, new IntentFilter(SERVICECMD));
//        mPsir.registerIntent();
        PowerManager pm = (PowerManager)getSystemService(Context.POWER_SERVICE);
        mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, this.getClass().getName());
        mWakeLock.setReferenceCounted(false);
    }

    @Override
    public void onDestroy() {
        unregisterReceiver(mIntentReceiver);
        if (mUnmountReceiver != null) {
            unregisterReceiver(mUnmountReceiver);
            mUnmountReceiver = null;
        }
//        mPsir.unregisterIntent();
        mWakeLock.release();
        super.onDestroy();
    }
    
    private final char hexdigits [] = new char [] {
            '0', '1', '2', '3',
            '4', '5', '6', '7',
            '8', '9', 'a', 'b',
            'c', 'd', 'e', 'f'
    };

    private void saveQueue(boolean full) {
        if (mOneShot) {
            return;
        }
        Editor ed = mPreferences.edit();
        //long start = System.currentTimeMillis();
        if (full) {
            StringBuilder q = new StringBuilder();
            
            // The current playlist is saved as a list of "reverse hexadecimal"
            // numbers, which we can generate faster than normal decimal or
            // hexadecimal numbers, which in turn allows us to save the playlist
            // more often without worrying too much about performance.
            // (saving the full state takes about 40 ms under no-load conditions
            // on the phone)
            int len = mPlayListLen;
            for (int i = 0; i < len; i++) {
                int n = mPlayList[i];
                if (n == 0) {
                    q.append("0;");
                } else {
                    while (n != 0) {
                        int digit = n & 0xf;
                        n >>= 4;
                        q.append(hexdigits[digit]);
                    }
                    q.append(";");
                }
            }
            //Log.i("@@@@ service", "created queue string in " + (System.currentTimeMillis() - start) + " ms");
            ed.putString("queue", q.toString());
            ed.putInt("cardid", mCardId);
        }
        ed.putInt("curpos", mPlayPos);
        if (mPlayer.isInitialized()) {
            ed.putLong("seekpos", mPlayer.position());
        }
        ed.putInt("repeatmode", mRepeatMode);
        ed.putInt("shufflemode", mShuffleMode);
        ed.commit();
  
        //Log.i("@@@@ service", "saved state in " + (System.currentTimeMillis() - start) + " ms");
    }

    private void reloadQueue() {
        String q = null;
        
        boolean newstyle = false;
        int id = mCardId;
        if (mPreferences.contains("cardid")) {
            newstyle = true;
            id = mPreferences.getInt("cardid", ~mCardId);
        }
        if (id == mCardId) {
            // Only restore the saved playlist if the card is still
            // the same one as when the playlist was saved
            q = mPreferences.getString("queue", "");
        }
        if (q != null && q.length() > 1) {
            //Log.i("@@@@ service", "loaded queue: " + q);
            String [] entries = q.split(";");
            int len = entries.length;
            ensurePlayListCapacity(len);
            for (int i = 0; i < len; i++) {
                if (newstyle) {
                    String revhex = entries[i];
                    int n = 0;
                    for (int j = revhex.length() - 1; j >= 0 ; j--) {
                        n <<= 4;
                        char c = revhex.charAt(j);
                        if (c >= '0' && c <= '9') {
                            n += (c - '0');
                        } else if (c >= 'a' && c <= 'f') {
                            n += (10 + c - 'a');
                        } else {
                            // bogus playlist data
                            len = 0;
                            break;
                        }
                    }
                    mPlayList[i] = n;
                } else {
                    mPlayList[i] = Integer.parseInt(entries[i]);
                }
            }
            mPlayListLen = len;

            int pos = mPreferences.getInt("curpos", 0);
            if (pos < 0 || pos >= len) {
                // The saved playlist is bogus, discard it
                mPlayListLen = 0;
                return;
            }
            mPlayPos = pos;
            
            // When reloadQueue is called in response to a card-insertion,
            // we might not be able to query the media provider right away.
            // To deal with this, try querying for the current file, and if
            // that fails, wait a while and try again. If that too fails,
            // assume there is a problem and don't restore the state.
            Cursor c = MusicUtils.query(this,
                        MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                        new String [] {"_id"}, "_id=" + mPlayList[mPlayPos] , null, null);
            if (c == null || c.getCount() == 0) {
                // wait a bit and try again
                SystemClock.sleep(3000);
                c = getContentResolver().query(
                        MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                        mCursorCols, "_id=" + mPlayList[mPlayPos] , null, null);
            }
            if (c != null) {
                c.close();
            }

            // Make sure we don't auto-skip to the next song, since that
            // also starts playback. What could happen in that case is:
            // - music is paused
            // - go to UMS and delete some files, including the currently playing one
            // - come back from UMS
            // (time passes)
            // - music app is killed for some reason (out of memory)
            // - music service is restarted, service restores state, doesn't find
            //   the "current" file, goes to the next and: playback starts on its
            //   own, potentially at some random inconvenient time.
            mOpenFailedCounter = 20;
            openCurrent();
            if (!mPlayer.isInitialized()) {
                // couldn't restore the saved state
                mPlayListLen = 0;
                return;
            }
            
            long seekpos = mPreferences.getLong("seekpos", 0);
            seek(seekpos >= 0 && seekpos < duration() ? seekpos : 0);