제가 초보라서 잘 모르겠는데요..

ListDB가 아래의 클랙스 쪽으로 연결이 되더군요..SQL인가..

public boolean deleteNode(int rowId){
  return mDB.delete(DB_TABLE,  "=" +rowId , null)>0;
  
 }
 
 public DB_source deleteAll(){
  Log.v("log_del","DB_del");
  mDB.execSQL("DELETE FROM protect_v1");
  return this; 
 }
아래처럼 쓰고 지우고 해도 안되요..
getDB_write();
DB_del();
closeDB();
arGeneral.remove(ListDB);
arGeneral.clear();
Adapter.notifyDataSetChanged();

저도 다른 소스를 가져온 거라서요.. 쫌 어렵네요..도와주세요..

이게 ListDB 클래스입니다.

public class List_DB extends ListActivity {
 ArrayList<String> arGeneral;
 public DB_source ListDB;
 private Cursor LCursor;
 private Toast mToast;
 private ArrayAdapter<String> Adapter;
 protected static final int DIALOG_YES_NO_MESSAGE = 0;
 
 protected void onCreate(Bundle savedInstanceState){
  super.onCreate(savedInstanceState);
  getDB_read();
  DB_look();
  
  
  Adapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,arGeneral);
  setListAdapter(Adapter);
  closeDB();
 }
 
 public void onListItemClick(ListView list,View view,int position,long id){
  String mes;
  //mes="Select Item="+arGeneral.get(position);
  //Toast.makeText(List_DB.this, mes, Toast.LENGTH_SHORT).show();
    
 }
 void getDB_write()
     {
   ListDB = new DB_source(this);
   ListDB.open("getwrite");
     }
 void getDB_read(){
   ListDB=new DB_source(this);
   ListDB.open("getread");
  }
    
 void closeDB()
 {
  if(ListDB != null)
   ListDB.close();
  
  ListDB = null;
 }
 void DB_input(String location)
 {
  ListDB.creatNode(location);
 }
 void DB_look()
 {
  arGeneral=new ArrayList<String>();
  Cursor cursor;
  cursor=ListDB.fetchAllNotes();
  String Result="";
  cursor.moveToFirst();
  
  if(cursor.isFirst())
     {
      Log.v("cursor loc","it's first of Cursor");
      String location=cursor.getString(0);
   arGeneral.add(location);
     }
  while(cursor.moveToNext()){
   String location=cursor.getString(0);
   arGeneral.add(location);
   
  }
  if(cursor.getCount()!=0){
   //mToast.makeText(List_DB.this, "안녕",Toast.LENGTH_SHORT);
   
  }else{
   //mToast.makeText(List_DB.this, "안녕",Toast.LENGTH_SHORT);
   
  }
  
  cursor.close();
  
  
 }
 void DB_del_All()
 {
  ListDB.deleteAll(); 
 }
 public boolean onCreateOptionsMenu(Menu menu) {
  super.onCreateOptionsMenu(menu);
  MenuItem item=menu.add(0,1,0,"DB_del");
  item.setIcon(R.drawable.icon);
  item.setAlphabeticShortcut('a');
  //menu.add(0,1,0,"吏쒖옣").setIcon(R.drawable.icon).setAlphabeticShortcut('a');
  menu.add(0,2,0,"萸먮꽔?꾧퉴?").setIcon(R.drawable.icon);
 
  return true;
 }

 public boolean onOptionsItemSelected(MenuItem item) {
  switch (item.getItemId()) {
  case 1:
   getDB_write();
   DB_del_All();
   closeDB();
    
   arGeneral.remove(arGeneral);
   arGeneral.clear();
   Adapter.notifyDataSetChanged();
   
   return true;
  
  }
  return false;
 }
}

그리고 이건 DB_soure 입니다.
public class DB_source {
 
 
 private static final String KEY_LOCATION ="db_location";
 

 
 
 private static final String DB_NAME="child_protected.db";
 private static final String DB_TABLE="protect_v1";
 private static final int DB_VERSION=1;
 
 private final Context mCtx;
 
 private DBHelper mDBHelper;
 private SQLiteDatabase mDB;
 
 private static final String DB_creat_table =
  "CREATE TABLE protect_v1(_id INTEGER PRIMARY KEY AUTOINCREMENT,"
   
   +"db_location TEXT NOT NULL"
   +");";
 
 private static final String ON_UPGRADE= "DROP TABLE IF EXISTS protect_v1";
 
 private static  class DBHelper extends SQLiteOpenHelper{
  DBHelper(Context context){
   super(context, DB_NAME, null, DB_VERSION);
  }

  @Override
  public void onCreate(SQLiteDatabase db) {
   // TODO Auto-generated method stub
   Log.v("DB.onc","DB_start");
   db.execSQL(DB_creat_table);
   
  }

  @Override
  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
   // TODO Auto-generated method stub
   db.execSQL(ON_UPGRADE);
   onCreate(db);
   
  } 
 }
 
 public DB_source(Context ctx){
  this.mCtx=ctx;
 }
 
 public DB_source open(String select) throws SQLException{
  
  mDBHelper = new DBHelper(mCtx);
  if(select =="getwrite"){
  mDB=mDBHelper.getWritableDatabase();
  Log.v("log_open","DB_wirte_open");
  }
  else if(select=="getread"){
  mDB=mDBHelper.getWritableDatabase();
  Log.v("log_open","DB_read_open"); 
  }
  else{
  Log.v("log_open_fall","DB_read_open_fall");  
  }
  return this;
 }
 
 public void close(){
  mDBHelper.close();
  Log.v("log_close","DB_close");
 }
 
 public long creatNode(String location){
  ContentValues row=new ContentValues();
  Log.v("log_input","DB_input");
  row.put(KEY_LOCATION, location);
  
  return mDB.insert(DB_TABLE, null, row);
 }
 
 
 public boolean deleteNode(int rowId){
  return mDB.delete(DB_TABLE,  "=" +rowId , null)>0;
  
 }
 
 public DB_source deleteAll(){
  Log.v("log_del","DB_del");
  mDB.execSQL("DELETE FROM protect_v1");
  return this;
  
 }
 
 public Cursor fetchAllNotes(){
  return mDB.query(DB_TABLE, new String[]{KEY_LOCATION}
  , null, null, null, null, null);
 }
 public Cursor fetchNote(int rowId) throws SQLException{
  Cursor mCursor=
   mDB.query(false, DB_TABLE,  new String[]{KEY_LOCATION},
    "="+rowId, null, null, null, null, null);
  if(mCursor !=null){
   mCursor.moveToFirst();
  }
  return mCursor;
 }
  public boolean updateNote(int rowId,int day,int time,String location,String gps_point){
      
         ContentValues args = new ContentValues();
         args.put(KEY_LOCATION, location);
               
         return mDB.update(DB_TABLE, args,  "=" + rowId, null) > 0;
     }
 

}