java - SQLite returned rows count is zero -

   public class sqliteprovider extends sqliteopenhelper {      private static sqlitedatabase sqlitedatabase ;        public sqliteprovider ( context context ) {         super ( context , database_name , null , database_version ) ;     }      @override     public void oncreate ( sqlitedatabase sqlitedatabase ) {         try {             . sqlitedatabase = . getwriteabaledatabase ( ) ;             . sqlitedatabase . execsql ( table_create ) ;             . sqlitedatabase . close ( ) ;         } catch ( exception exception ) {             log . ( log_tag , "exception `" + exception . tostring ( ) + "`" ) ;         }     }      private void insert ( string column1value , string column2value ) {         try {             sqlitedatabase = . getwritabledatabase ( ) ;             sqlitedatabase . execsql ( query_to_insert ) ;             sqlitedatabase . close ( ) ;         } catch ( exception exception ) {             log . ( log_tag , "exception `" + exception . tostring ( ) + "`" ) ;         }     }      private string selectcolumn1bycolumn2 ( string column2value ) {         try {             sqlitedatabase . getwritabledatabase ( ) ;             cursor = sqlitedatabase . rawquery ( select_query ) ;             sqlitedatabase . close ( )         } catch ( exception exception ) {             log . ( log_tag , "exception `" + exception . tostring ( ) + "`" ) ;         }         if ( cursor . getcount ( ) > 0 ) {             return cursor . getstring ( 0 ) ;         } else {              log . ( log_tag , "selectcolumn1bycolumn2 row count 0 " ) ;              return "";         }     }      public string doit ( ) {         insert ( variable1 , variable2 ) ;         return selectcolumn1bycolumn2 ( variable2 ) ;     } } 

all methods use same sqlitedatabase object , each of calls getwritabledatabase in beginning. function doit ( ) return empty string , log row count 0 ( selectcolumn1bycolumn2 row count zero ) , no 1 exception. transaction , without , both of not work how right?

update april 8

i have done

add block sqlitedatabase . close ( )

add cursor . close ( ) when necessary before sqlitedatabase . close ( )

change cursor . getstring ( 0 ) cursor . getstring ( cursor . getcolumnindex ( table_column1 ) )

change if ( cursor . getcount ( ) > 0 ) if ( cursor . movetofirst ( ) )

and returns row count 0 , don`t work on jelly bean 4.2 - android application crashes

the reason why not getting desired result because closing database first , reading cursor.

if first read cursur, , when finished using cursor close database, should work.

the user named alibi gives explanation in answer: clicky

1) cursor pointer data returned query, doesn't contain data query. increase performance/efficiency (large resultsets aren't read @ once -> less memory used). therefore, if close database, cursor can't retrieve data -> it's empty.

2) when close cursor, associated resources released -> can't access data associated cursor (since has been released), can make new queries using or other cursors. when close database, can't query anymore (until re-open it).

3) close cursors. otherwise run problems - gc complain if cursor isn't closed , new queries blocked.

4) if close when app finishes, yes

again, credit goes alibi.

update

private string selectcolumn1bycolumn2 ( string column2value ) {     try {         sqlitedatabase . getwritabledatabase ( ) ;         cursor = sqlitedatabase . rawquery ( select_query ) ;          cursor.movetofirst();         if ( cursor . getcount ( ) > 0 ) {             return cursor . getstring ( 0 ) ;         } else {              log . ( log_tag , "selectcolumn1bycolumn2 row count 0 " ) ;              return "";         }     } catch ( exception exception ) {         log . ( log_tag , "exception `" + exception . tostring ( ) + "`" ) ;     } {         cursor.close();          sqlitedatabase . close ( );     } } 

cursor.close , sqlitedatabase.close() moved block. ensure database , cursor gets cleaned when done using it.

also added cursor.movetofirst(); call before first call getcount();

not 100% sure it's needed it's worth try.