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Android应用开发-MP3音乐播放器代码实现（三）
2013年5月29 简、美音乐播放器开发记录
这篇博客是接着上一篇博客的，点击列表会进入播放的Activity,在这个Activity会接收到从前面的Activity传来的数据，在通过这些数据来启动服务来播放音乐，整个过程很简单，需要注意的是我们要接收的数据是哪些内容，还有我们向Service要传什么样的数据，这是根据自己的开发思路和需求来决定的，等一下你们会看到小巫到底往Service传了些什么东西，然而这些数据到底起什么作用，需要慢慢去体会，因为这是需要一点一点去调试的。
好了，下面贴一下整个Activity的实现代码，主要是播放的各种状态的实现，因为这个音乐播放器并没有完全开发完，所以朋友们需要弄清楚这一点。如果对代码的实现有不清楚的，可以给小巫留言，小巫有空一定给大家解答。
PlayerActivity.java代码：
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;/** * 播放音乐界面 * @author wwj * 从主界面传递过来歌曲的Id、歌曲名、歌手、歌曲路径、播放状态 */public class PlayerActivity extends Activity{ private TextView musicTitle = null; private TextView musicArtist = null; private Button previousBtn; // 上一首 private Button repeatBtn; // 重复（单曲循环、全部循环） private Button playBtn; // 播放（播放、暂停） private Button shuffleBtn; // 随机播放 private Button nextBtn; // 下一首 private Button searchBtn; //查找歌曲 private Button queueBtn; //歌曲列表 private SeekBar music_progressBar; //歌曲进度 private TextView currentProgress; //当前进度消耗的时间 private TextView finalProgress; //歌曲时间 private String title; //歌曲标题 private String artist; //歌曲艺术家 private String url; //歌曲路径 private int listPosition; //播放歌曲在mp3Infos的位置 private int currentTime; //当前歌曲播放时间 private int duration; //歌曲长度 private int flag; //播放标识 private int repeatState; private final int isCurrentRepeat = 1; // 单曲循环 private final int isAllRepeat = 2; // 全部循环 private final int isNoneRepeat = 3; // 无重复播放 private boolean isPlaying; // 正在播放 private boolean isPause; // 暂停 private boolean isNoneShuffle; // 顺序播放 private boolean isShuffle; // 随机播放 private List<Mp3Info> mp3Infos; private PlayerReceiver playerReceiver; public static final String UPDATE_ACTION = "com.wwj.action.UPDATE_ACTION"; //更新动作 public static final String CTL_ACTION = "com.wwj.action.CTL_ACTION"; //控制动作 public static final String MUSIC_CURRENT = "com.wwj.action.MUSIC_CURRENT"; //音乐当前时间改变动作 public static final String MUSIC_DURATION = "com.wwj.action.MUSIC_DURATION";//音乐播放长度改变动作 public static final String MUSIC_PLAYING = "com.wwj.action.MUSIC_PLAYING"; //音乐正在播放动作 public static final String REPEAT_ACTION = "com.wwj.action.REPEAT_ACTION"; //音乐重复播放动作 public static final String SHUFFLE_ACTION = "com.wwj.action.SHUFFLE_ACTION";//音乐随机播放动作 @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); } /** * 从界面上根据id获取按钮 */ 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); } /** * 给每一个按钮设置监听器 */ 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数据 */ @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(); } /** * 初始化界面 */ public void initView() { musicTitle.setText(title); musicArtist.setText(artist); music_progressBar.setProgress(currentTime); music_progressBar.setMax(duration); switch (repeatState) { case isCurrentRepeat: // 单曲循环 shuffleBtn.setClickable(false); repeatBtn.setBackgroundResource(R.drawable.repeat_current_selector); break; case isAllRepeat: // 全部循环 shuffleBtn.setClickable(false); repeatBtn.setBackgroundResource(R.drawable.repeat_all_selector); break; case isNoneRepeat: // 无重复 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) { //如果播放信息是正在播放 Toast.makeText(PlayerActivity.this, "正在播放--" + title, 1).show(); } else if(flag == AppConstant.PlayerMsg.PLAY_MSG) { //如果是点击列表播放歌曲的话 play(); } playBtn.setBackgroundResource(R.drawable.play_selector); isPlaying = true; isPause = false; } /** * 反注册广播 */ @Override protected void onStop() { super.onStop(); unregisterReceiver(playerReceiver); } @Override protected void onDestroy() { super.onDestroy(); } /** * 控件点击事件 * @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: //重复播放音乐 if (repeatState == isNoneRepeat) { repeat_one(); shuffleBtn.setClickable(false); //是随机播放变为不可点击状态 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: // 单曲循环 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: // 全部循环 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: // 无重复 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: //随机播放状态 Intent shuffleIntent = new Intent(SHUFFLE_ACTION); if (isNoneShuffle) { //如果当前状态为非随机播放，点击按钮之后改变状态为随机播放 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; } } } /** * 实现监听Seekbar的类 * @author wwj * */ private class SeekBarChangeListener implements OnSeekBarChangeListener { @Override public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { if(fromUser) { audioTrackChange(progress); //用户控制进度的改变 } } @Override public void onStartTrackingTouch(SeekBar seekBar) { } @Override public void onStopTrackingTouch(SeekBar seekBar) { } } /** * 播放音乐 */ public void play() { //开始播放的时候为顺序播放 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); } /** * 随机播放 */ 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); } /** * 单曲循环 */ public void repeat_one() { Intent intent = new Intent(CTL_ACTION); intent.putExtra("control", 1); sendBroadcast(intent); } /** * 全部循环 */ public void repeat_all() { Intent intent = new Intent(CTL_ACTION); intent.putExtra("control", 2); sendBroadcast(intent); } /** * 顺序播放 */ 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, "没有上一首了", 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, "没有下一首了", Toast.LENGTH_SHORT).show(); } } /** * 用来接收从service传回来的广播的内部类 * @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)) { //获取Intent中的current消息，current代表当前正在播放的歌曲 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; } } } } }以上代码主要有以下几点实现：
1. 播放状态（上一首、下一首、暂停音乐、播放音乐、重复播放、随机播放）
2. 进度更新（自定义Seekbar，Seekbar触发时间控制音乐播放的位置）
3. 接收来自Service的广播，对播放时间，歌曲信息的UI更新。
要注意的地方：
1. 在onResume里接收来自HomeActivity里通过Intent传过来的数据，它是保存在bundle当中的，所以可以通过Bundle来取数据。
2. 通过startSercice来启动服务，在启动之前我们往服务传的数据
/** * 播放音乐 */ public void play() { //开始播放的时候为顺序播放 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); }可以看到只有url（音乐播放路径）、listPosition(列表的点击位置，也就是mp3Infos的位置）、MSG(代表播放信息）。这几个是来控制播放的，在Service会很清楚看到这几个参数的作用。这会在下一篇博客中介绍。
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