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Android應用開發-MP3音樂播放器程式碼實現（三）

2013年5月29 簡、美音樂播放器開發記錄

這篇部落格是接著上一篇部落格的，點選列表會進入播放的Activity,在這個Activity會接收到從前面的Activity傳來的資料，在通過這些資料來啟動服務來播放音樂，整個過程很簡單，需要注意的是我們要接收的資料是哪些內容，還有我們向Service要傳什麼樣的資料，這是根據自己的開發思路和需求來決定的，等一下你們會看到小巫到底往Service傳了些什麼東西，然而這些資料到底起什麼作用，需要慢慢去體會，因為這是需要一點一點去除錯的。

好了，下面貼一下整個Activity的實現程式碼，主要是播放的各種狀態的實現，因為這個音樂播放器並沒有完全開發完，所以朋友們需要弄清楚這一點。如果對程式碼的實現有不清楚的，可以給小巫留言，小巫有空一定給大家解答。

PlayerActivity.java程式碼：

package com.wwj.sb.activity;import java.util.List;import android.app.Activity;import android.content.BroadcastReceiver;import
 
 android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.os.Bundle;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.SeekBar;import android.widget.SeekBar.OnSeekBarChangeListener;import
 
 android.widget.TextView;import android.widget.Toast;import com.wwj.sb.domain.AppConstant;import com.wwj.sb.domain.Mp3Info;import com.wwj.sb.utils.MediaUtil;/** * 播放音樂介面 * @author wwj * 從主介面傳遞過來歌曲的Id、歌曲名、歌手、歌曲路徑、播放狀態 */public class PlayerActivity extends Activity{ private TextView musicTitle = null; private TextView musicArtist = null; private Button previousBtn; // 上一首 private Button repeatBtn;  // 重複（單曲迴圈、全部迴圈） private Button playBtn;   // 播放（播放、暫停） private Button shuffleBtn; // 隨機播放 private Button nextBtn;  // 下一首 private Button searchBtn; //查詢歌曲 private Button queueBtn; //歌曲列表 private SeekBar music_progressBar;  //歌曲進度 private TextView currentProgress; //當前進度消耗的時間 private TextView finalProgress;  //歌曲時間   private String title;  //歌曲標題 private String artist;  //歌曲藝術家 private String url;   //歌曲路徑 private int listPosition; //播放歌曲在mp3Infos的位置 private int currentTime; //當前歌曲播放時間 private int duration;  //歌曲長度 private int flag;   //播放標識  private int repeatState; private final int isCurrentRepeat = 1; // 單曲迴圈 private final int isAllRepeat = 2;   // 全部迴圈 private final int isNoneRepeat = 3;  // 無重複播放 private boolean isPlaying;     // 正在播放 private boolean isPause;     // 暫停 private boolean isNoneShuffle;    // 順序播放 private boolean isShuffle;    // 隨機播放  private List<Mp3Info> mp3Infos;   private PlayerReceiver playerReceiver;  public static final String UPDATE_ACTION = "com.wwj.action.UPDATE_ACTION"; //更新動作 public static final String CTL_ACTION = "com.wwj.action.CTL_ACTION";  //控制動作 public static final String MUSIC_CURRENT = "com.wwj.action.MUSIC_CURRENT"; //音樂當前時間改變動作 public static final String MUSIC_DURATION = "com.wwj.action.MUSIC_DURATION";//音樂播放長度改變動作 public static final String MUSIC_PLAYING = "com.wwj.action.MUSIC_PLAYING"; //音樂正在播放動作 public static final String REPEAT_ACTION = "com.wwj.action.REPEAT_ACTION"; //音樂重複播放動作 public static final String SHUFFLE_ACTION = "com.wwj.action.SHUFFLE_ACTION";//音樂隨機播放動作  @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.play_activity_layout);  musicTitle = (TextView) findViewById(R.id.musicTitle);  musicArtist = (TextView) findViewById(R.id.musicArtist);    findViewById();  setViewOnclickListener();  mp3Infos = MediaUtil.getMp3Infos(PlayerActivity.this);  playerReceiver = new PlayerReceiver();  IntentFilter filter = new IntentFilter();  filter.addAction(UPDATE_ACTION);  filter.addAction(MUSIC_CURRENT);  filter.addAction(MUSIC_DURATION);  registerReceiver(playerReceiver, filter);   }  /**  * 從介面上根據id獲取按鈕  */ private void findViewById() {  previousBtn = (Button) findViewById(R.id.previous_music);  repeatBtn = (Button) findViewById(R.id.repeat_music);  playBtn = (Button) findViewById(R.id.play_music);  shuffleBtn = (Button) findViewById(R.id.shuffle_music);  nextBtn = (Button) findViewById(R.id.next_music);  searchBtn = (Button) findViewById(R.id.search_music);  queueBtn = (Button) findViewById(R.id.play_queue);  music_progressBar = (SeekBar) findViewById(R.id.audioTrack);  currentProgress = (TextView) findViewById(R.id.current_progress);  finalProgress = (TextView) findViewById(R.id.final_progress); }   /**  * 給每一個按鈕設定監聽器  */ private void setViewOnclickListener() {  ViewOnclickListener ViewOnClickListener = new ViewOnclickListener();  previousBtn.setOnClickListener(ViewOnClickListener);  repeatBtn.setOnClickListener(ViewOnClickListener);  playBtn.setOnClickListener(ViewOnClickListener);  shuffleBtn.setOnClickListener(ViewOnClickListener);  nextBtn.setOnClickListener(ViewOnClickListener);  searchBtn.setOnClickListener(ViewOnClickListener);  queueBtn.setOnClickListener(ViewOnClickListener);  music_progressBar.setOnSeekBarChangeListener(new SeekBarChangeListener()); }  /**  * 在OnResume中初始化和接收Activity資料  */ @Override protected void onResume() {  super.onResume();  Intent intent = getIntent();  Bundle bundle = intent.getExtras();  title = bundle.getString("title");  artist = bundle.getString("artist");  url = bundle.getString("url");  listPosition = bundle.getInt("listPosition");  repeatState = bundle.getInt("repeatState");  isShuffle = bundle.getBoolean("shuffleState");  flag = bundle.getInt("MSG");  currentTime = bundle.getInt("currentTime");  duration = bundle.getInt("duration");  initView(); }  /**  * 初始化介面  */ public void initView() {  musicTitle.setText(title);  musicArtist.setText(artist);  music_progressBar.setProgress(currentTime);  music_progressBar.setMax(duration);  switch (repeatState) {  case isCurrentRepeat: // 單曲迴圈   shuffleBtn.setClickable(false);   repeatBtn.setBackgroundResource(R.drawable.repeat_current_selector);   break;  case isAllRepeat: // 全部迴圈   shuffleBtn.setClickable(false);   repeatBtn.setBackgroundResource(R.drawable.repeat_all_selector);   break;  case isNoneRepeat: // 無重複   shuffleBtn.setClickable(true);   repeatBtn.setBackgroundResource(R.drawable.repeat_none_selector);   break;  }  if(isShuffle) {   isNoneShuffle = false;   shuffleBtn.setBackgroundResource(R.drawable.shuffle_selector);   repeatBtn.setClickable(false);  } else {   isNoneShuffle = true;   shuffleBtn.setBackgroundResource(R.drawable.shuffle_none_selector);   repeatBtn.setClickable(true);  }  if(flag == AppConstant.PlayerMsg.PLAYING_MSG) { //如果播放資訊是正在播放   Toast.makeText(PlayerActivity.this, "正在播放--" + title, 1).show();  }  else if(flag == AppConstant.PlayerMsg.PLAY_MSG) { //如果是點選列表播放歌曲的話   play();  }  playBtn.setBackgroundResource(R.drawable.play_selector);  isPlaying = true;  isPause = false; } /**  * 反註冊廣播  */ @Override protected void onStop() {  super.onStop();  unregisterReceiver(playerReceiver); }  @Override protected void onDestroy() {  super.onDestroy(); } /**  * 控制元件點選事件  * @author wwj  *  */ private class ViewOnclickListener implements OnClickListener {  Intent intent = new Intent();  @Override  public void onClick(View v) {   switch(v.getId()) {   case R.id.play_music:    if (isPlaying) {     playBtn.setBackgroundResource(R.drawable.pause_selector);     intent.setAction("com.wwj.media.MUSIC_SERVICE");     intent.putExtra("MSG", AppConstant.PlayerMsg.PAUSE_MSG);     startService(intent);     isPlaying = false;     isPause = true;         } else if (isPause) {     playBtn.setBackgroundResource(R.drawable.play_selector);     intent.setAction("com.wwj.media.MUSIC_SERVICE");     intent.putExtra("MSG", AppConstant.PlayerMsg.CONTINUE_MSG);     startService(intent);     isPause = false;     isPlaying = true;    }    break;   case R.id.previous_music:  //上一首歌曲    previous_music();    break;   case R.id.next_music:   //下一首歌曲    next_music();    break;   case R.id.repeat_music:   //重複播放音樂    if (repeatState == isNoneRepeat) {     repeat_one();     shuffleBtn.setClickable(false); //是隨機播放變為不可點選狀態     repeatState = isCurrentRepeat;     } else if (repeatState == isCurrentRepeat) {     repeat_all();     shuffleBtn.setClickable(false);     repeatState = isAllRepeat;    } else if (repeatState == isAllRepeat) {     repeat_none();     shuffleBtn.setClickable(true);     repeatState = isNoneRepeat;    }    Intent intent = new Intent(REPEAT_ACTION);    switch (repeatState) {    case isCurrentRepeat: // 單曲迴圈     repeatBtn       .setBackgroundResource(R.drawable.repeat_current_selector);     Toast.makeText(PlayerActivity.this, R.string.repeat_current,       Toast.LENGTH_SHORT).show();               intent.putExtra("repeatState", isCurrentRepeat);     sendBroadcast(intent);     break;    case isAllRepeat: // 全部迴圈     repeatBtn       .setBackgroundResource(R.drawable.repeat_all_selector);     Toast.makeText(PlayerActivity.this, R.string.repeat_all,       Toast.LENGTH_SHORT).show();     intent.putExtra("repeatState", isAllRepeat);     sendBroadcast(intent);     break;    case isNoneRepeat: // 無重複     repeatBtn       .setBackgroundResource(R.drawable.repeat_none_selector);     Toast.makeText(PlayerActivity.this, R.string.repeat_none,       Toast.LENGTH_SHORT).show();     intent.putExtra("repeatState", isNoneRepeat);     break;    }    break;   case R.id.shuffle_music:   //隨機播放狀態    Intent shuffleIntent = new Intent(SHUFFLE_ACTION);    if (isNoneShuffle) {   //如果當前狀態為非隨機播放，點選按鈕之後改變狀態為隨機播放     shuffleBtn       .setBackgroundResource(R.drawable.shuffle_selector);     Toast.makeText(PlayerActivity.this, R.string.shuffle,       Toast.LENGTH_SHORT).show();     isNoneShuffle = false;     isShuffle = true;     shuffleMusic();     repeatBtn.setClickable(false);     shuffleIntent.putExtra("shuffleState", true);     sendBroadcast(shuffleIntent);    } else if (isShuffle) {     shuffleBtn       .setBackgroundResource(R.drawable.shuffle_none_selector);     Toast.makeText(PlayerActivity.this, R.string.shuffle_none,       Toast.LENGTH_SHORT).show();     isShuffle = false;     isNoneShuffle = true;     repeatBtn.setClickable(true);     shuffleIntent.putExtra("shuffleState", false);     sendBroadcast(shuffleIntent);    }    break;   }  } }  /**  * 實現監聽Seekbar的類  * @author wwj  *  */ private class SeekBarChangeListener implements OnSeekBarChangeListener {  @Override  public void onProgressChanged(SeekBar seekBar, int progress,    boolean fromUser) {   if(fromUser) {    audioTrackChange(progress); //使用者控制進度的改變   }  }  @Override  public void onStartTrackingTouch(SeekBar seekBar) {     }  @Override  public void onStopTrackingTouch(SeekBar seekBar) {     }   }  /**  * 播放音樂  */ public void play() {  //開始播放的時候為順序播放  repeat_none();  Intent intent = new Intent();  intent.setAction("com.wwj.media.MUSIC_SERVICE");  intent.putExtra("url", url);  intent.putExtra("listPosition", listPosition);  intent.putExtra("MSG", flag);  startService(intent); } /**  * 隨機播放  */ public void shuffleMusic() {  Intent intent = new Intent(CTL_ACTION);  intent.putExtra("control", 4);  sendBroadcast(intent); } public void audioTrackChange(int progress) {  Intent intent = new Intent();  intent.setAction("com.wwj.media.MUSIC_SERVICE");  intent.putExtra("url", url);  intent.putExtra("listPosition", listPosition);  if(isPause) {   intent.putExtra("MSG", AppConstant.PlayerMsg.PAUSE_MSG);  }  else {   intent.putExtra("MSG", AppConstant.PlayerMsg.PROGRESS_CHANGE);  }  intent.putExtra("progress", progress);  startService(intent); } /**  * 單曲迴圈  */ public void repeat_one() {  Intent intent = new Intent(CTL_ACTION);  intent.putExtra("control", 1);  sendBroadcast(intent); }  /**  * 全部迴圈  */ public void repeat_all() {  Intent intent = new Intent(CTL_ACTION);  intent.putExtra("control", 2);  sendBroadcast(intent); } /**  * 順序播放  */ public void repeat_none() {  Intent intent = new Intent(CTL_ACTION);  intent.putExtra("control", 3);  sendBroadcast(intent); } /**  * 上一首  */ public void previous_music() {  playBtn.setBackgroundResource(R.drawable.play_selector);  listPosition = listPosition - 1;  if(listPosition >= 0) {   Mp3Info mp3Info = mp3Infos.get(listPosition);  //上一首MP3   musicTitle.setText(mp3Info.getTitle());   musicArtist.setText(mp3Info.getArtist());   url = mp3Info.getUrl();   Intent intent = new Intent();   intent.setAction("com.wwj.media.MUSIC_SERVICE");   intent.putExtra("url", mp3Info.getUrl());   intent.putExtra("listPosition", listPosition);   intent.putExtra("MSG", AppConstant.PlayerMsg.PRIVIOUS_MSG);   startService(intent);  }  else {   Toast.makeText(PlayerActivity.this, "沒有上一首了", Toast.LENGTH_SHORT).show();  } }  /**  * 下一首  */ public void next_music() {  playBtn.setBackgroundResource(R.drawable.play_selector);  listPosition = listPosition + 1;  if(listPosition <= mp3Infos.size() - 1) {   Mp3Info mp3Info = mp3Infos.get(listPosition);   url = mp3Info.getUrl();   musicTitle.setText(mp3Info.getTitle());   musicArtist.setText(mp3Info.getArtist());   Intent intent = new Intent();   intent.setAction("com.wwj.media.MUSIC_SERVICE");   intent.putExtra("url", mp3Info.getUrl());   intent.putExtra("listPosition", listPosition);   intent.putExtra("MSG", AppConstant.PlayerMsg.NEXT_MSG);   startService(intent);  } else {   Toast.makeText(PlayerActivity.this, "沒有下一首了", Toast.LENGTH_SHORT).show();  } }   /**  * 用來接收從service傳回來的廣播的內部類  * @author wwj  *  */ public class PlayerReceiver extends BroadcastReceiver {  @Override  public void onReceive(Context context, Intent intent) {   String action = intent.getAction();   if(action.equals(MUSIC_CURRENT)) {    currentTime = intent.getIntExtra("currentTime", -1);    currentProgress.setText(MediaUtil.formatTime(currentTime));    music_progressBar.setProgress(currentTime);   } else if(action.equals(MUSIC_DURATION)) {    int duration = intent.getIntExtra("duration", -1);    music_progressBar.setMax(duration);    finalProgress.setText(MediaUtil.formatTime(duration));   } else if(action.equals(UPDATE_ACTION)) {    //獲取Intent中的current訊息，current代表當前正在播放的歌曲    listPosition = intent.getIntExtra("current", -1);    url = mp3Infos.get(listPosition).getUrl();    if(listPosition >= 0) {     musicTitle.setText(mp3Infos.get(listPosition).getTitle());     musicArtist.setText(mp3Infos.get(listPosition).getArtist());    }    if(listPosition == 0) {     finalProgress.setText(MediaUtil.formatTime(mp3Infos.get(listPosition).getDuration()));     playBtn.setBackgroundResource(R.drawable.pause_selector);     isPause = true;    }   }  }   } }

1. 播放狀態（上一首、下一首、暫停音樂、播放音樂、重複播放、隨機播放）

2. 進度更新（自定義Seekbar，Seekbar觸發時間控制音樂播放的位置）

3. 接收來自Service的廣播，對播放時間，歌曲資訊的UI更新。

要注意的地方：

1. 在onResume裡接收來自HomeActivity裡通過Intent傳過來的資料，它是儲存在bundle當中的，所以可以通過Bundle來取資料。

2. 通過startSercice來啟動服務，在啟動之前我們往服務傳的資料

/**  * 播放音樂  */ public void play() {  //開始播放的時候為順序播放  repeat_none();  Intent intent = new Intent();  intent.setAction("com.wwj.media.MUSIC_SERVICE");  intent.putExtra("url", url);  intent.putExtra("listPosition", listPosition);  intent.putExtra("MSG", flag);  startService(intent); }

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