大图：GUI向用户显示其播放列表的列表.用户选择一个.程序将所选的播放列表传递到下一个活动,该活动将显示该播放列表中的歌曲.
问题：我可以显示播放列表并注册用户选择,但似乎无法显示该播放列表中的歌曲.
是的,我看到以下问题：
How to query for songs in playlists on Android SDK?
Given an Android music playlist name, how can one find the songs in the playlist?
如您在我的代码中看到的那样,我已尽力实现这些解决方案,但无济于事.
注意事项：我正在Galaxy Nexus上进行测试,因此没有SD卡.只是内部存储和云中的音乐.我需要它在任何情况下(内部,外部或云)都可以工作.目前,它们都不起作用.
//@SuppressWarnings ("serial)")
public class CreationActivity extends Activity {
private final String [] STAR= {"*"};
//reads in all songs to an array
@Override
public void onCreate (Bundle savedInstanceState){
super.onCreate(savedInstanceState);
//set layout view and assign to variable
setContentView(R.layout.creation);
TableLayout myLayout = (TableLayout)findViewById(R.id.creationLayout);
try {
Bundle extras = getIntent().getExtras();
if (extras!=null){
//get the desired playlist and ID
String playlist = extras.getString("playlist");
Long playlistID = extras.getLong("playlistID");
ArrayList<song> songs = new ArrayList<song>();
//read in the songs from the playlist
String[] proj = {MediaStore.Audio.Playlists.Members.TITLE,
MediaStore.Audio.Playlists.Members.ARTIST,
MediaStore.Audio.Playlists.Members.DURATION};
//method 1
Cursor songCursor = getContentResolver().query(MediaStore.Audio.Playlists.Members.getContentUri(null,playlistID),
proj,
null,
null,
null);
//method 2
/*
Cursor songCursor = getContentResolver().query(Uri.parse("content://com.google.android.music.MusicContent/playlists/members"),
proj,
null,
null,
null);
*/
//method 3
/*
Uri membersUri = MediaStore.Audio.Playlists.Members.getContentUri("internal", playlistID);
Cursor membersCursor = managedQuery(membersUri, STAR, null, null, null);
*/
//then this part with methods 1 and 2
/*
if (songCursor.getCount() > 0) {
songCursor.moveToFirst();
do {
song currSong = new song();
currSong.title = songCursor.getString(0);
currSong.artist = songCursor.getString(1);
songs.add(currSong);
} while (songCursor.moveToNext());
}
songCursor.close();
*/
//or this part with method 3
/*
membersCursor.moveToFirst();
for(int s= 0; s<membersCursor.getCount(); s++,
membersCursor.moveToNext()){
song currSong = new song();
currSong.title = songCursor.getString(0);
currSong.artist = songCursor.getString(1);
songs.add(currSong);
}
membersCursor.close();
*/
}else{
Toast.makeText(getBaseContext(), "No songs",Toast.LENGTH_LONG).show();
}
} catch (NumberFormatException e){
}
}
}
编译期间没有错误.但是“不幸的是,音乐应用程序意外退出了.”每次.
谢谢您的帮助！
解决方法:
我想到了.关键是将播放列表ID用作URI中的字符串.请参见下面的代码.
这是将获得播放列表名称和ID的部分：
String[] proj = {MediaStore.Audio.Playlists.NAME, MediaStore.Audio.Playlists._ID};
Uri playlistUri = Uri.parse("content://com.google.android.music.MusicContent/playlists");
Cursor playlistCursor = getContentResolver().query(playlistUri, proj, null, null, null);
if (playlistCursor.getCount() > 0) {
playlistCursor.moveToFirst();
do {
nameList.add(playlistCursor.getString(0));
idList.add(playlistCursor.getLong(1));
} while (playlistCursor.moveToNext());
}
然后,一旦获得播放列表ID,便可以在播放列表中查询歌曲.这是代码中实际查询信息并将其全部放入数组列表的部分.注意：“歌曲”是我在其他地方定义的类,其中readSong是一种将值分配给各种值(标题,艺术家等)的方法.
ArrayList<song> songs = new ArrayList<song>();
//read songs into library from the correct playlist
String[] proj = {MediaStore.Audio.Playlists.Members.TITLE, MediaStore.Audio.Playlists.Members.ARTIST, MediaStore.Audio.Playlists.Members.DURATION, MediaStore.Audio.Playlists.Members._ID};
Uri songUri = Uri.parse("content://com.google.android.music.MusicContent/playlists/" + playlistID + "/members");
Cursor songCursor = getContentResolver().query(songUri, proj, null, null, null);
if (songCursor.getCount() > 0) {
songCursor.moveToFirst();
do {
//create dummy song
song currSong = new song();
//read info to dummy var
currSong.readSong(songCursor);
//add instance to collection
songs.add(currSong);
} while (songCursor.moveToNext());
}
songCursor.close();
我希望这对其他为此感到挣扎的人有所帮助！让我知道您是否对我的方法或方法有任何意见！
标签：mediastore,android 来源： https://codeday.me/bug/20191101/1980291.html
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