"Attempted to access a cursor after it has been closed"
"Attempted to access a cursor after it has been closed"
我无法理解这个问题。我试图从其他 Whosebug 问题中获得解决方案,但未能获得解决方案。我之前没有收到此错误。但是,现在我不知道下面所述的代码有什么问题。请帮我解决一下这个。我被这个问题困住了。
public void getAlbumsLists() {
final Uri uri = MediaStore.Audio.Albums.EXTERNAL_CONTENT_URI;
final String _id = MediaStore.Audio.Albums._ID;
final String album = MediaStore.Audio.Media.ALBUM;
final String album_name = MediaStore.Audio.AlbumColumns.ALBUM;
final String artist = MediaStore.Audio.AlbumColumns.ARTIST;
final String tracks = MediaStore.Audio.AlbumColumns.NUMBER_OF_SONGS;
// final String data=MediaStore.Audio.Albums.ALBUM_ID; // NO
// final String id1=MediaStore.Audio.Albums.ALBUM_ID;
final String tit = MediaStore.Audio.Albums.ALBUM; //NO
final String nam = MediaStore.Audio.Albums.ALBUM_KEY; // NO
final String typ = MediaStore.Audio.Media.MIME_TYPE; // NO
final String art = MediaStore.Audio.Albums.ALBUM_ART; //<<<< CAN GET
final String artstkey = MediaStore.Audio.Artists.ARTIST_KEY; //<<<< CAN GET
final String frstyr = MediaStore.Audio.AlbumColumns.FIRST_YEAR; //<<<< CAN GET
final String lstyr = MediaStore.Audio.AlbumColumns.LAST_YEAR; //<<<< CAN GET
final String artstid = "artist_id"; //<<<< CAN GET
final String[] columns = {"*"};
Cursor cursor = getActivity().getContentResolver().query(uri, columns, null, null, null);
// Lists the columns in the cursor
for (String s : cursor.getColumnNames()) {
Log.d("COLUMNS", "Column = " + s);
}
while (cursor.moveToNext()) {
String id = (cursor.getString(cursor.getColumnIndex(_id)));
String name = cursor.getString(cursor.getColumnIndex(album_name));
String artist2 = cursor.getString(cursor.getColumnIndex(artist));
String nr = cursor.getString(cursor.getColumnIndex(tracks));
String x = (cursor.getString(cursor.getColumnIndex(album)));
//String data1=cursor.getString(cursor.getColumnIndexOrThrow(data)); //<<<< NOT A COLUMN
// String id2=cursor.getString(cursor.getColumnIndex(data));
//String title=cursor.getString(cursor.getColumnIndex(tit)); //<<<< NOT A COLUMN
//String name1=cursor.getString(cursor.getColumnIndex(nam)); //<<<< NOT A COLUMN
//String type=cursor.getString(cursor.getColumnIndex(typ)); //<<<< NOT A COLUMN
// AVAIALABLE COLUMNS
String artwork = cursor.getString(cursor.getColumnIndex(art)); //<<<< ADDED
String artistkey = cursor.getString(cursor.getColumnIndex(artstkey)); //<<<< ADDED
String artistid = cursor.getString(cursor.getColumnIndex(artstid)); //<<<< ADDED
String minyear = cursor.getString(cursor.getColumnIndex(frstyr));
String maxyear = cursor.getString(cursor.getColumnIndex(lstyr));
s = new albumInfo(id, name, artist2, nr, artwork, x); // EXCLUDED
albumList.add(s);
cursor.close();
recyclerView1.setAdapter(albumAdapter); // EXCLUDED
}
}
将 cursor.close();
移到 while 循环之外。
已编辑..
while 循环迭代后第一次关闭游标,因此需要将其放在 while 之外。
我可以提出三个改进方案。
- 您需要先将光标移动到 first 才能访问它以从光标中获取数据。
- 没有返回或游标为空时需要关闭游标。
- 将光标移到 while 循环之外。
所以我想建议你像下面这样重写代码。
// After you have fetched the data from cursor
if(cursor == null) return;
if(cursor.size() == 0) {
cursor.close();
return;
}
for (String s : cursor.getColumnNames()) {
Log.d("COLUMNS", "Column = " + s);
}
// Move the cursor to the first position.
cursor.moveToFirst();
do {
String id = (cursor.getString(cursor.getColumnIndex(_id)));
String name = cursor.getString(cursor.getColumnIndex(album_name));
String artist2 = cursor.getString(cursor.getColumnIndex(artist));
String nr = cursor.getString(cursor.getColumnIndex(tracks));
String x = (cursor.getString(cursor.getColumnIndex(album)));
// ... Other code
} while (cursor.moveToNext());
recyclerView1.setAdapter(albumAdapter); // EXCLUDED
// Move the cursor outside of while loop
cursor.close();
我无法理解这个问题。我试图从其他 Whosebug 问题中获得解决方案,但未能获得解决方案。我之前没有收到此错误。但是,现在我不知道下面所述的代码有什么问题。请帮我解决一下这个。我被这个问题困住了。
public void getAlbumsLists() {
final Uri uri = MediaStore.Audio.Albums.EXTERNAL_CONTENT_URI;
final String _id = MediaStore.Audio.Albums._ID;
final String album = MediaStore.Audio.Media.ALBUM;
final String album_name = MediaStore.Audio.AlbumColumns.ALBUM;
final String artist = MediaStore.Audio.AlbumColumns.ARTIST;
final String tracks = MediaStore.Audio.AlbumColumns.NUMBER_OF_SONGS;
// final String data=MediaStore.Audio.Albums.ALBUM_ID; // NO
// final String id1=MediaStore.Audio.Albums.ALBUM_ID;
final String tit = MediaStore.Audio.Albums.ALBUM; //NO
final String nam = MediaStore.Audio.Albums.ALBUM_KEY; // NO
final String typ = MediaStore.Audio.Media.MIME_TYPE; // NO
final String art = MediaStore.Audio.Albums.ALBUM_ART; //<<<< CAN GET
final String artstkey = MediaStore.Audio.Artists.ARTIST_KEY; //<<<< CAN GET
final String frstyr = MediaStore.Audio.AlbumColumns.FIRST_YEAR; //<<<< CAN GET
final String lstyr = MediaStore.Audio.AlbumColumns.LAST_YEAR; //<<<< CAN GET
final String artstid = "artist_id"; //<<<< CAN GET
final String[] columns = {"*"};
Cursor cursor = getActivity().getContentResolver().query(uri, columns, null, null, null);
// Lists the columns in the cursor
for (String s : cursor.getColumnNames()) {
Log.d("COLUMNS", "Column = " + s);
}
while (cursor.moveToNext()) {
String id = (cursor.getString(cursor.getColumnIndex(_id)));
String name = cursor.getString(cursor.getColumnIndex(album_name));
String artist2 = cursor.getString(cursor.getColumnIndex(artist));
String nr = cursor.getString(cursor.getColumnIndex(tracks));
String x = (cursor.getString(cursor.getColumnIndex(album)));
//String data1=cursor.getString(cursor.getColumnIndexOrThrow(data)); //<<<< NOT A COLUMN
// String id2=cursor.getString(cursor.getColumnIndex(data));
//String title=cursor.getString(cursor.getColumnIndex(tit)); //<<<< NOT A COLUMN
//String name1=cursor.getString(cursor.getColumnIndex(nam)); //<<<< NOT A COLUMN
//String type=cursor.getString(cursor.getColumnIndex(typ)); //<<<< NOT A COLUMN
// AVAIALABLE COLUMNS
String artwork = cursor.getString(cursor.getColumnIndex(art)); //<<<< ADDED
String artistkey = cursor.getString(cursor.getColumnIndex(artstkey)); //<<<< ADDED
String artistid = cursor.getString(cursor.getColumnIndex(artstid)); //<<<< ADDED
String minyear = cursor.getString(cursor.getColumnIndex(frstyr));
String maxyear = cursor.getString(cursor.getColumnIndex(lstyr));
s = new albumInfo(id, name, artist2, nr, artwork, x); // EXCLUDED
albumList.add(s);
cursor.close();
recyclerView1.setAdapter(albumAdapter); // EXCLUDED
}
}
将 cursor.close();
移到 while 循环之外。
已编辑..
while 循环迭代后第一次关闭游标,因此需要将其放在 while 之外。
我可以提出三个改进方案。
- 您需要先将光标移动到 first 才能访问它以从光标中获取数据。
- 没有返回或游标为空时需要关闭游标。
- 将光标移到 while 循环之外。
所以我想建议你像下面这样重写代码。
// After you have fetched the data from cursor
if(cursor == null) return;
if(cursor.size() == 0) {
cursor.close();
return;
}
for (String s : cursor.getColumnNames()) {
Log.d("COLUMNS", "Column = " + s);
}
// Move the cursor to the first position.
cursor.moveToFirst();
do {
String id = (cursor.getString(cursor.getColumnIndex(_id)));
String name = cursor.getString(cursor.getColumnIndex(album_name));
String artist2 = cursor.getString(cursor.getColumnIndex(artist));
String nr = cursor.getString(cursor.getColumnIndex(tracks));
String x = (cursor.getString(cursor.getColumnIndex(album)));
// ... Other code
} while (cursor.moveToNext());
recyclerView1.setAdapter(albumAdapter); // EXCLUDED
// Move the cursor outside of while loop
cursor.close();