android初学者的探索之路（Android音乐播放器）

简单介绍一下自己，二流大学毕业，cs专业，为了找工作学习android，一直不能入门，觉得光看书不行，还是的写代码。

于是我想到一个项目可以把android的知识点串联起来，音乐播放器。

1.activity ，各种界面

2.contentprovider，从手机上读取本地音乐

3.service，音乐播放写在service中，即使没有界面也可以放

4.broadcastreceiver，activity和service的数据传递，用intent，但是的用sendbroadcast传送最好

5.mediaplay，实现音乐的播放暂停，等操作

由于本人水品有限，一切都在摸索中，先贴上没有用service和broadcastreceiver的音乐播放器的代码。

public class MainActivity extends ActionBarActivity {ListView lv;RelativeLayout rLayout;Button forwButton;Button nextButton;Button stopButton;MediaPlayer mediaPlayer = new MediaPlayer();ArrayList musicList = new ArrayList();// 当前点击音乐内容的时间轴位置int music_content_postion;// 当前点击音乐的位置int music_postion;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);initView();putMusicToList();setMusicListToAdapter();musicEvent();}// 当当前activity状态破坏时保存变量，以便恢复时使用@Overrideprotected void onSaveInstanceState(Bundle outState) {super.onSaveInstanceState(outState);outState.putInt("music_postion", music_postion);outState.putInt("music_content_postion", music_content_postion);}// 以便恢复时使用@Overrideprotected void onRestoreInstanceState(Bundle savedInstanceState) {super.onRestoreInstanceState(savedInstanceState);this.music_postion = savedInstanceState.getInt("music_postion");this.music_content_postion = savedInstanceState.getInt("music_content_postion");}@Overrideprotected void onPause() {super.onPause();if (mediaPlayer.isPlaying()) {music_content_postion = mediaPlayer.getCurrentPosition();mediaPlayer.stop();}}@Overrideprotected void onResume() {super.onResume();if (music_content_postion > 0) {if (music_postion == 0) {startMediaPlayer(1);} else {startMediaPlayer(music_postion);mediaPlayer.seekTo(music_content_postion);music_content_postion = 0;}}}@Overrideprotected void onDestroy() {super.onDestroy();mediaPlayer.release();}private void initView() {lv = (ListView) findViewById(R.id.listView_show_music);forwButton = (Button) findViewById(R.id.button_forward);nextButton = (Button) findViewById(R.id.button_next);stopButton = (Button) findViewById(R.id.button_show_music);rLayout = (RelativeLayout) findViewById(R.id.con_music);}private void putMusicToList() {// 用contentresolver获得音乐Cursor cursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null,null);while (cursor.moveToNext()) {Music music = new Music();String musicName = cursor.getString(cursor.getColumnIndex(Media.DISPLAY_NAME));music.setMusic_name(musicName);byte[] musicPath = cursor.getBlob(cursor.getColumnIndex(Media.DATA));music.setMusic_path(new String(musicPath, 0, musicPath.length - 1));String musicAut = cursor.getString(cursor.getColumnIndex(Media.ARTIST));music.setMusic_author(musicAut);musicList.add(music);}}private void setMusicListToAdapter() {List> listitems = new ArrayList>();for (int i = 0; i < musicList.size(); i++) {Map item = new HashMap();item.put("name", musicList.get(i).getMusic_name());item.put("author", musicList.get(i).getMusic_author());listitems.add(item);}SimpleAdapter simpleAdapter = new SimpleAdapter(this, listitems,R.layout.line, new String[] { "name", "author" }, new int[] {R.id.textView_name, R.id.textView_author });lv.setAdapter(simpleAdapter);}private void musicEvent() {lv.setOnItemClickListener(new OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> parent, View view,int position, long id) {rLayout.setVisibility(View.VISIBLE);music_postion = position;startMediaPlayer(position);}});stopButton.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Button button = (Button) v;if (mediaPlayer.isPlaying()) {mediaPlayer.pause();button.setText("Start");} else {mediaPlayer.start();button.setText("Stop");}}});forwButton.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {if (music_postion == 0) {music_postion=musicList.size() - 1;startMediaPlayer(musicList.size() - 1);} else {music_postion=music_postion - 1;startMediaPlayer(music_postion);}}});nextButton.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {if (music_postion == musicList.size() - 1) {music_postion=0;startMediaPlayer(music_postion);} else {music_postion=music_postion+1;startMediaPlayer(music_postion);}}});}private void startMediaPlayer(int position) {try {if (mediaPlayer.isPlaying()) {mediaPlayer.stop();}mediaPlayer.reset();mediaPlayer.setDataSource(musicList.get(position).getMusic_path());mediaPlayer.prepare();mediaPlayer.start();} catch (IOException e) {e.printStackTrace();}}}

这个仅仅是开始雏形，我会继续重构，添加代码

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