MATCH with selectArgs looking like *queryTerm* stopped working on Android 5.0+

问题

This is addendum to my question SQLiteDatabase Cursor empty only on Android 5.0+ devices. That one will be closed as I was not sure what is causing the bug - thought it was a cursor note being properly filled. Now I have discovered what is causing empty cursor.

Up to Android 5.0, search suggestions work by querying the database with the query:

SELECT rowid AS _id, suggest_text_1, suggest_text_2, rowid AS suggest_intent_data_id 
FROM fts 
WHERE (fts MATCH ?) //for example '*e*'

As of Android 5.0+, this does not work any more. I've done dozens of testings and the select query returns nothing to the Cursor object if I set selectionArgs to "*" + query + "*"

String selection = FTS3_TABLE + " MATCH ?";
String[] selectionArgs = new String[]{"*" + query + "*"};

On Android 5.0+ it will work ONLY if selectionArgs are either query or query + "*". If I put asterisk before the query, it will stop working.

NOTE: I tested by querying a letter e, not a special character.

Database querying looks like this and it worked flawlessly up to Android 5.0:

String[] columns = new String[]{
                BaseColumns._ID,
                KEY_QUESTION,
                KEY_ANSWER,
                SearchManager.SUGGEST_COLUMN_INTENT_DATA_ID};
String selection = FTS3_TABLE + " MATCH ?";
String[] selectionArgs = new String[]{"*" + query + "*"};    

//mColumnMap
map.put(KEY_QUESTION, KEY_QUESTION);
map.put(KEY_ANSWER, KEY_ANSWER);
map.put(KEY_CARDID, KEY_CARDID);
map.put(KEY_CARDSET, KEY_CARDSET);
map.put(BaseColumns._ID, "rowid AS " +
         BaseColumns._ID);
map.put(SearchManager.SUGGEST_COLUMN_INTENT_DATA_ID, "rowid AS " +
                SearchManager.SUGGEST_COLUMN_INTENT_DATA_ID);
map.put(SearchManager.SUGGEST_COLUMN_SHORTCUT_ID, "rowid AS " +
                SearchManager.SUGGEST_COLUMN_SHORTCUT_ID);
//mColumnMap part ends

SQLiteQueryBuilder builder = new SQLiteQueryBuilder();
        builder.setTables(FTS3_TABLE);
        builder.setProjectionMap(mColumnMap);

Cursor cursor = builder.query(db,
                columns, selection, selectionArgs, null, null, null);

String temp = DatabaseUtils.dumpCursorToString(cursor); //empty string on Android 5.0+

As you can see, nothing complex or extraordinary.

Why I can no longer use query with asterisk on both sides of it?

What has changed as of Android 5.0 in this part?

回答1:

MATCH '*foo*' queries never worked correctly in any version of sqlite. The fact that you got some results earlier was just a coincidence. Just the prefix form MATCH 'foo*' (and MATCH 'foo') are supported.

Lollipop ships with a newer version of sqlite. For detailed list of changes between sqlite versions, see the changelog.

来源：https://stackoverflow.com/questions/30709715/match-with-selectargs-looking-like-queryterm-stopped-working-on-android-5-0

标签

android

android-sqlite

android-5.0-lollipop