Android SQLite not deleting row by id -

i trying delete row given specific id , see update reflected in listview, row not deleted. same process works update, not delete. here code:

mainactivity.java

...  @override     public void onpositiveclick(dialogfragment dialog, int which) {              //shared preferences             sharedpreferences pref = getsharedpreferences(editlog.pref_filename, 0);             long id = 0;             string date = "";             string hours = "";             string lessontype = "";             string weathercondition = "";             if (!(pref == null)) {                 id = pref.getlong("rowid", 0);                 date = pref.getstring("date", "");                 hours = pref.getstring("hours", "");                 lessontype = pref.getstring("lessontype", "");                 weathercondition = pref.getstring("weathercondition", "");             }              if (which == 2) {                 lessonlogdbhelper dbhelp = new lessonlogdbhelper(getapplicationcontext());                 final sqlitedatabase db = dbhelp.getwritabledatabase();                 db.delete(lessonlogcontract.logentry.table_name, "_id=?", new string[]{long.tostring(id)});             } else {                 lessonlogdbhelper dbhelp = new lessonlogdbhelper(getapplicationcontext());                 final sqlitedatabase db = dbhelp.getwritabledatabase();                 final contentvalues values = new contentvalues();                 values.put(lessonlogcontract.logentry.cn_date, date);                 values.put(lessonlogcontract.logentry.cn_hours, hours);                 values.put(lessonlogcontract.logentry.cn_lesson_type, lessontype);                 values.put(lessonlogcontract.logentry.cn_weather, weathercondition);                 db.update(lessonlogcontract.logentry.table_name, values, "_id=" + id, null);              }              fragmenttransaction transaction = getsupportfragmentmanager().begintransaction();             transaction.replace(r.id.content_main, new drivinglog());             transaction.commit();      }  ... 

if == 2, means user clicked on delete button, id (in db) of item clicked passed, , call delete. process works update, not delete.

edit: neat things

something weird found if try update entry, delete any single entry db. if don't try update first, can't.

here table def:

lessonlogcontract

package com.example.name.drivinglessona3;  import android.provider.basecolumns; import android.util.stringbuilderprinter;  public class lessonlogcontract {     private lessonlogcontract() {}      public static class logentry implements basecolumns {         public static final string table_name = "lesson";         public static final string cn_date = "date";         public static final string cn_hours = "hours";         public static final string cn_lesson_type = "lesson_type";         public static final string cn_weather = "weather";     } } 

lessonlogdbhelper

package com.example.name.drivinglessona3;  import android.content.context; import android.database.sqlite.sqlitedatabase; import android.database.sqlite.sqliteopenhelper;    public class lessonlogdbhelper extends sqliteopenhelper {     // if change database schema, must increment database version.     private static final string sql_create_entries =             "create table " + lessonlogcontract.logentry.table_name + " (" +                     lessonlogcontract.logentry._id + " integer primary key," +                     lessonlogcontract.logentry.cn_date+ " text," +                     lessonlogcontract.logentry.cn_hours+ " text," +                     lessonlogcontract.logentry.cn_lesson_type+ " text," +                     lessonlogcontract.logentry.cn_weather + " text)";      private static final string sql_delete_entries =             "drop table if exists " + lessonlogcontract.logentry.table_name;      public static final int database_version = 1;     public static final string database_name = "logentry.db";      public lessonlogdbhelper(context context) {         super(context, database_name, null, database_version);     }     public void oncreate(sqlitedatabase db) {         db.execsql(sql_create_entries);     }     public void onupgrade(sqlitedatabase db, int oldversion, int newversion) {         // database cache online data, upgrade policy         // discard data , start on         db.execsql(sql_delete_entries);         oncreate(db);     }     public void ondowngrade(sqlitedatabase db, int oldversion, int newversion) {         onupgrade(db, oldversion, newversion);     } } 

solved

when clicking delete button, wasn't saving _id sharedpreferences, in mainactivity getting wrong value of id.

try this:

public void delete(int id) {         sqlitedatabase db = getwritabledatabase();         db.delete("mst_item", "itemid=" + id, null);         db.close(); }