递归遍历 SD 卡目录下的所有音乐文件，并点击条目后进入相应的播放界面

        在编写音乐 app 时，需要用到SD 卡目录下的音乐文件。遍历（递归） SD 卡目录下的所有音乐文件，显示在相应的条目后，点击相应条目后就可以进入播放界面。点击条目时还需要传递参数可以用 Parcelable 实现传参。在前文中也有该 Parcelable 传参的示例。

       效果如下：

遍历 SD 卡目录下的文件：

MusicCursorListActivity.java :

    

package com.crazy.crazymusicplayer;import android.app.Activity;import android.content.Context;import android.database.Cursor;import android.os.Bundle;import android.provider.MediaStore;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.CursorAdapter;import android.widget.ListView;import android.widget.TextView;/** * MediaStore.Audio.Media.EXTERNAL_CONTENT_URI 对应字段 * 歌曲ID：MediaStore.Audio.Media._ID  * 歌曲的名称：MediaStore.Audio.Media.TITLE * 歌曲的专辑名：MediaStore.Audio.Media.ALBUM  * 歌曲的歌手名：MediaStore.Audio.Media.ARTIST * 歌曲文件的路径：MediaStore.Audio.Media.DATA  * 歌曲的总播放时长：MediaStore.Audio.Media.DURATION * 歌曲文件的大小：MediaStore.Audio.Media.SIZE *  */public class MusicCursorListActivity extends Activity {private ListView mListView;private FileCursorAdapter mAdapter;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_music_list_layout);mListView = (ListView) findViewById(R.id.music_list_view);/** * Android自身具有维护媒体库的功能 * 1.系统创建了一个SQLITE数据库存放所有音乐资源 * 2.MediaScaner类负责扫描系统文件，添加音乐资源到数据库 。 * 什么时间执行扫描操作：1.启动手机,2.插入拔出Sdcard时,3.接收到扫描广播时 */Cursor cursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null,MediaStore.Audio.Media.TITLE_KEY);mAdapter = new FileCursorAdapter(this, cursor);mListView.setAdapter(mAdapter);}public class FileCursorAdapter extends CursorAdapter {private LayoutInflater layoutInflater;public FileCursorAdapter(Context context, Cursor c) {super(context, c, FLAG_AUTO_REQUERY);layoutInflater = LayoutInflater.from(context);}@Overridepublic void bindView(View view, Context arg1, Cursor cursor) {TextView titleTxt = (TextView) view.findViewById(R.id.music_title_txt);TextView articsTxt = (TextView) view.findViewById(R.id.music_artics_txt);String title = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.TITLE));titleTxt.setText(title);articsTxt.setText(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST)));}@Overridepublic View newView(Context arg0, Cursor arg1, ViewGroup arg2) {return layoutInflater.inflate(R.layout.item_music_cursor_layout,null);}}}

列表：

MusicListActivity.java :

package com.crazy.crazymusicplayer;import android.app.Activity;import android.content.Context;import android.content.Intent;import android.os.Bundle;import android.os.Environment;import android.os.Handler;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.BaseAdapter;import android.widget.ListView;import android.widget.TextView;import java.io.File;import java.util.ArrayList;public class MusicListActivity extends Activity implements OnItemClickListener{private ListView mListView;private Handler mHandler = new Handler();private ArrayList<MusicBean> mMusicList = new ArrayList<>();private FileAdapter mAdapter;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_music_list_layout);mListView = (ListView) findViewById(R.id.music_list_view);mListView.setOnItemClickListener(this);mAdapter = new FileAdapter(this);mListView.setAdapter(mAdapter);new Thread(new Runnable() {@Overridepublic void run() {scanFileList(Environment.getExternalStorageDirectory());/** ListView刷新必须在UI线程中 通过Handler消息机制发送刷新代码到UI主线程执行 */mHandler.post(new Runnable() {@Overridepublic void run() {mAdapter.setListData(mMusicList);}});}}).start();}/** * 扫描Sdcard（外部存储）下所有文件 */public void scanFileList(File parentFile) {File[] listFile = parentFile.listFiles();int length = listFile.length;if (listFile != null) {for (int i = 0; i < length; i++) {File file = listFile[i];if (file.isDirectory()) {scanFileList(file);} else {//file://music/p/xx.mp3if (file.getName().endsWith(".mp3")) {MusicBean music = new MusicBean();String fileName = file.getName();music.setMusicName(fileName.substring(0, fileName.length()-".mp3".length()));music.setMusicPath(file.getAbsolutePath());mMusicList.add(music);}}}}}public class FileAdapter extends BaseAdapter {private ArrayList<MusicBean> list = new ArrayList<>();private LayoutInflater layoutInflater;public FileAdapter(Context context) {layoutInflater = LayoutInflater.from(context);}public void setListData(ArrayList<MusicBean> list) {this.list = list;notifyDataSetChanged();}@Overridepublic int getCount() {return list.size();}@Overridepublic Object getItem(int position) {return list.get(position);}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {if (convertView == null) {convertView = layoutInflater.inflate(R.layout.item_music_list_layout, null);}MusicBean file = (MusicBean) getItem(position);TextView nameTxt = (TextView) convertView;nameTxt.setText(file.getMusicName());return convertView;}}@Overridepublic void onItemClick(AdapterView<?> parent, View view, int position,long id) {Intent intent = new Intent(this, MainActivity.class);intent.putParcelableArrayListExtra("MUSIC_LIST", mMusicList);intent.putExtra("CURRENT_POSITION", position);startActivity(intent);/*MusicBean musicBean = (MusicBean) parent.getAdapter().getItem(position);Intent intent = new Intent(this, MainActivity.class);intent.putExtra("MUSIC_BEAN",musicBean);startActivity(intent);*/}}

Parcelable.java :

package com.crazy.crazymusicplayer;import android.os.Parcel;import android.os.Parcelable;public class MusicBean implements Parcelable{private String musicName;private String musicPath;public String getMusicName() {return musicName;}public void setMusicName(String musicName) {this.musicName = musicName;}public String getMusicPath() {return musicPath;}public void setMusicPath(String musicPath) {this.musicPath = musicPath;}@Overridepublic int describeContents() {return 0;}@Overridepublic void writeToParcel(Parcel dest, int flags) {dest.writeString(musicName);dest.writeString(musicPath);}/** * 必须用 public static final 修饰符   * 对象必须用 CREATOR  */public static final Creator<MusicBean> CREATOR = new Creator<MusicBean>() {@Overridepublic MusicBean createFromParcel(Parcel source) {String name = source.readString();String path = source.readString();MusicBean music = new MusicBean();music.setMusicName(name);music.setMusicPath(path);return music;}@Overridepublic MusicBean[] newArray(int size) {return new MusicBean[size];}};}

所需的布局文件：

activity_music_list_layout.xml :

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    android:background="@drawable/player_bg_bar" >    <ListView        android:id="@+id/music_list_view"        android:layout_width="match_parent"        android:layout_height="match_parent" >    </ListView></LinearLayout>

item_music_cursor_layout.xml :

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >    <TextView        android:id="@+id/music_title_txt"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="center_vertical"        android:paddingLeft="?android:attr/listPreferredItemPaddingLeft"        android:paddingRight="?android:attr/listPreferredItemPaddingRight"        android:textSize="18sp"        android:text="小明"        android:textColor="@android:color/white" />    <TextView        android:id="@+id/music_artics_txt"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="center_vertical"        android:paddingLeft="?android:attr/listPreferredItemPaddingLeft"        android:paddingRight="?android:attr/listPreferredItemPaddingRight"        android:text="明天"        android:textColor="@android:color/holo_blue_dark" /></LinearLayout>

activity_music_list_layout.xml :

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    android:background="@drawable/player_bg_bar" >    <ListView        android:id="@+id/music_list_view"        android:layout_width="match_parent"        android:layout_height="match_parent" >    </ListView></LinearLayout>

item_music_list_layout.xml :

<?xml version="1.0" encoding="utf-8"?><TextView xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@android:id/text1"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:textAppearance="?android:attr/textAppearanceListItemSmall"    android:gravity="center_vertical"    android:textColor="@android:color/white"    android:paddingLeft="?android:attr/listPreferredItemPaddingLeft"    android:paddingRight="?android:attr/listPreferredItemPaddingRight"    android:minHeight="?android:attr/listPreferredItemHeightSmall"/>