如何对ListViewAdapter的MergeCursor进行排序或重新排序
如何对ListViewAdapter的MergeCursor进行排序或重新排序
提问于 2016-06-28 19:24:28
我正在为我的案例研究开发一个简单的社交媒体。我能够从用户关注的人那里检索到这篇文章。截图如下：
正如您所看到的，问题是帖子没有按照日期/id排序。相反，它是根据用户关注的人进行排序的。这是因为我只使用mergecursor合并游标。下面是我的代码的一部分：
ListView listviewFeed = (ListView) findViewById(R.id.listviewFeed);
Cursor cursorFeed = DataAdapters.getFeed(dbHelper, strUserID);
//This code is for retrieving user's own posts
Cursor cursorFollowing = DataAdapters.getFollowing(dbHelper,strUserID);
//This code is for retrieving the followed users.
if(cursorFollowing.getCount()>0) {
for (int intCtr = 0; intCtr < cursorFollowing.getCount(); intCtr++) {
int intUseridI = cursorFollowing.getColumnIndex(Tables.FollowTable.COLUMN_USERID);
String strUseridI = cursorFollowing.getString(intUseridI);
Cursor cursorFollowingFeed = DataAdapters.getFeed(dbHelper, strUseridI);
\\This code is for retrieving the posts of the people the user follows.
if(intCtr>0)
{
mergeCursor = new MergeCursor(new Cursor[]{mergeCursor, cursorFollowingFeed});
}else {
mergeCursor = new MergeCursor(new Cursor[]{cursorFeed, cursorFollowingFeed});
}
//This code is for merging the cursors.
if (intCtr + 1 == cursorFollowing.getCount()) {
cursorFollowing.close();
} else {
cursorFollowing.moveToNext();
}
}
ListViewAdapterMeasurement adapterMeasurement = new ListViewAdapterMeasurement(this, mergeCursor);
listviewFeed.setAdapter(adapterMeasurement);
}else
{
ListViewAdapterMeasurement adapterMeasurement = new ListViewAdapterMeasurement(this, cursorFeed);
listviewFeed.setAdapter(adapterMeasurement);
}这一切都运行良好。我只想按日期或ID排序帖子。
有没有办法对MergeCursor进行排序？
回答 1
Stack Overflow用户
发布于 2016-06-28 20:55:29
我想没有办法对MergeCursor进行排序，所以我试着考虑其他方法。
我像这样修改了我的查询：
public static Cursor getFeed (DBHelper dbHelper, String strUserID)
{
SQLiteDatabase db = dbHelper.getReadableDatabase();
Cursor cursorFollowing = getFollowing(dbHelper,strUserID);
String strQuery = "SELECT * FROM feed_tbl WHERE "+ Tables.FeedTable.COLUMN_USERID + "="+strUserID;
if(cursorFollowing.getCount()>0)
{
for(int intCtr=0;intCtr<cursorFollowing.getCount();intCtr++)
{
int intUseridI = cursorFollowing.getColumnIndex(Tables.FollowTable.COLUMN_USERID);
String strUseridI = cursorFollowing.getString(intUseridI);
String strConcatQuery = " OR "+ Tables.FeedTable.COLUMN_USERID + "="+strUseridI;
if (intCtr + 1 == cursorFollowing.getCount()) {
cursorFollowing.close();
} else {
cursorFollowing.moveToNext();
}
strQuery = strQuery +""+strConcatQuery;
Log.v(TAG,strQuery);
}
}
Cursor cursor = db.rawQuery(strQuery+" ORDER BY "+ Tables.FeedTable.COLUMN_ID + " DESC",null);
if (cursor != null) {
cursor.moveToFirst();
}
return cursor;
}日志标记上的结果如下：
V/FeedMe: SELECT * FROM feed_tbl WHERE feed_userid=1 OR feed_userid=2 OR feed_userid=4 OR feed_userid=5
只是为了让那些和我有同样问题的人明白这一点，那就是MergeCursor排序。没有这样的方法来排序MERGECURSOR :)
谢谢！
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/38074914
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