我想查询给定播放列表的成员.我有正确的播放列表ID,并且想要使用managedQuery()来查看有问题的播放列表成员.
我所拥有的是：
private String [] columns = {
MediaStore.Audio.Playlists.Members.PLAYLIST_ID,MediaStore.Audio.Playlists.Members.TITLE,};
Uri membersUri = MediaStore.Audio.Playlists.Members.getContentUri(volume,playlistId);
Cursor tCursor = managedQuery(membersUri,columns,null,null);
我不知道音量参数是什么.我试过这个：
MediaStore.Audio.Playlists.EXTERNAL_CONTENT_URI.toString()为“volume”参数.
这给我一个有效的内容URI,看起来像：
content://media/external/audio/playlists/2/members
但是,我的光标返回null.我可能离开了基地 – 我知道我想做的很简单.
解决方法
字符串“external”用作MediaStore.Audio.Playlists.Members.getContentUri(volume,playlistId)中的卷
此活动将打印Android上的歌曲,播放列表及其内容.
import android.app.Activity;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
public class PlaylistActivity extends Activity {
private final String [] STAR= {"*"};
private final String TAG= "list";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.main);
Log.i(TAG,"All the titles");
Uri allaudio_uri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
Cursor ca= managedQuery(allaudio_uri,STAR,null);
for(ca.moveToFirst(); !ca.isAfterLast(); ca.moveToNext()){
if(ca.isFirst()){ // print all the fields of the first song
for(int k= 0; k<ca.getColumnCount(); k++)
Log.i(TAG," "+ca.getColumnName(k)+"="+ca.getString(k));
}else{ // but just the titles of the res
Log.i(TAG,ca.getString(ca.getColumnIndex("title")));
}
}
Log.i(TAG,"--------------------------");
Log.i(TAG,"All the playlists");
Uri playlist_uri= MediaStore.Audio.Playlists.EXTERNAL_CONTENT_URI;
Cursor cursor= managedQuery(playlist_uri,null);
cursor.moveToFirst();
for(int r= 0; r<cursor.getCount(); r++,cursor.moveToNext()){
Log.i(TAG,"-----");
Log.i(TAG,"Playlist " + cursor.getString(cursor.getColumnIndex("name")));
for(int k= 0; k<cursor.getColumnCount(); k++)
Log.i(TAG,cursor.getColumnName(k)+"="+cursor.getString(k));
// the members of this playlist
int id= cursor.getInt(0);
Uri membersUri = MediaStore.Audio.Playlists.Members.getContentUri("external",id);
Cursor membersCursor = managedQuery(membersUri,null);
membersCursor.moveToFirst();
for(int s= 0; s<membersCursor.getCount(); s++,membersCursor.moveToNext())
Log.i(TAG," "+membersCursor.getString(membersCursor.getColumnIndex("title")));
membersCursor.close();
}
cursor.close();
}
}
