如何从数据库中删除选定的列表视图项

Question

how to delete listview selected possition id value from database my code just only listview position value which is not equal to database value i want to delete listview selected position value from listview also from database and show KEY_TIME value of selected item in toast how to do that??

          msglist.setOnItemLongClickListener(new OnItemLongClickListener() {
   // setting onItemLongClickListener and passing the position to the function
          @Override
  public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
        int position, long arg3) {

              DatabaseHandler db = new DatabaseHandler(MsgActivity.this);


        Log.d("LOGInG VALUE", "Value: " + String.valueOf(arg3));


                      db.Delete_Contact(position);



              return true;
   }
 });


   public class DatabaseHandler extends SQLiteOpenHelper {

    String CREATE_INBOX_TABLE = "CREATE TABLE " + TABLE_INBOX + "("
+ KEY_INBOXID + " INTEGER PRIMARY KEY," + KEY_MSG + " TEXT,"+ KEY_TIME + " TEXT" + ")";
public void Delete_Contact(int id) {
//   String string =String.valueOf(id);
    SQLiteDatabase db = this.getWritableDatabase();
    db.delete(TABLE_INBOX, KEY_INBOXID + " =? ",  new String[] { 
       String.valueOf(id) });

            db.close();
}


    }

Answer 1

  DataBaseManager  data = new DataBaseManager(context.getApplicationContext());

                 String QUERY = "SELECT * FROM Cart Where id= "your id";

                    Cursor  cursor = data.selectQuery(QUERY);
    int count = cursor.getCount();
                   if (count <= 0) {

                }
             else {
                data.Delete("YOUR DATABASE NAME", "YOUR ID");
                list.remove(position);
                notifyDataSetChanged();
                }

DatabaseMangerClass

        public class DataBaseManager extends SQLiteOpenHelper {

            // The Android's default system path of your application database.

            @SuppressLint("SdCardPath")
            private static String DB_PATH = "data/data/com.Salsoft.pharmapacks/";
            private static String DB_NAME = "Cart.sqlite";
            private SQLiteDatabase myDataBase;
            private SQLiteDatabase myData;
            private Context myContext;

            // /data/data/com.salsoft.savingdata/db/SavingData.sqlite

            /**
             * Constructor Takes and keeps a reference of the passed context in order to
             * access to the application assets and resources.
             * 
             * @param context
             */
            public DataBaseManager(Context context) {
                super(context, DB_NAME, null, 1);
                this.myContext = context;
                Boolean isSDPresent = android.os.Environment.getExternalStorageState()
                        .equals(android.os.Environment.MEDIA_MOUNTED);

                if (isSDPresent) {
                    // yes SD-card is present
                } else {
                    // Sorry
                }
            }

            /**
             * Creates a empty database on the system and rewrites it with your own
             * database.
             * */
            public void createDataBase() throws IOException {

                boolean dbExist = checkDataBase();
                if (dbExist) {
                    // do nothing - database already exist
                } else {
                    File directory = new File(DB_PATH);
                    directory.mkdirs();
                    CopyFiles();
                }
            }

            private void CopyFiles() {
                try {
                    InputStream is = myContext.getAssets().open(DB_NAME);
                    File outfile = new File(DB_PATH, DB_NAME);
                    outfile.getParentFile().mkdirs();
                    outfile.createNewFile();

                    if (is == null) {
                        throw new RuntimeException("stream is null");
                    } else {
                        FileOutputStream out = new FileOutputStream(outfile);
                        byte buf[] = new byte[128];
                        do {
                            int numread = is.read(buf);
                            if (numread <= 0)
                                break;
                            out.write(buf, 0, numread);
                        } while (true);

                        is.close();
                        out.close();
                    }

                } catch (IOException e) {
                    throw new RuntimeException(e);
                }

            }

            /**
             * Check if the database already exist to avoid re-copying the file each
             * time you open the application.
             * 
             * @return true if it exists, false if it doesn't
             */
            private boolean checkDataBase() {

                SQLiteDatabase checkDB = null;

                try {
                    String myPath = DB_PATH + DB_NAME;
                    checkDB = SQLiteDatabase.openDatabase(myPath, null,
                            SQLiteDatabase.OPEN_READWRITE);

                } catch (SQLiteException e) {

                }

                if (checkDB != null) {
                    checkDB.close();
                }

                return checkDB != null ? true : false;
            }

            public void openDataBase() throws SQLException {

                // Open the database
                String myPath = DB_PATH + DB_NAME;
                myDataBase = SQLiteDatabase.openDatabase(myPath, null,
                        SQLiteDatabase.OPEN_READWRITE);
            }

            @Override
            public synchronized void close() {
                if (myDataBase != null)
                    myDataBase.close();
                super.close();
            }

            public void insert(String table, String num, ContentValues content) {
                String myPath = DB_PATH + DB_NAME;

                myData = SQLiteDatabase.openDatabase(myPath, null,
                        SQLiteDatabase.OPEN_READWRITE);
                myData.insert(table, num, content);

            }

            public void update(String tablename, ContentValues content, String productid) {
                String myPath = DB_PATH + DB_NAME;
                myData = SQLiteDatabase.openDatabase(myPath, null,
                        SQLiteDatabase.OPEN_READWRITE);
                myData.update(tablename, content, "productid = ?",
                        new String[] { productid });

            }

            public void Delete(String tablename, String productid) {
                String myPath = DB_PATH + DB_NAME;
                myData = SQLiteDatabase.openDatabase(myPath, null,
                        SQLiteDatabase.OPEN_READWRITE);

                myData.delete(tablename, "productid = ?", new String[] { productid });

            }

            @Override
            public void onCreate(SQLiteDatabase db) {
            }

            @Override
            public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            }

            // ---retrieve records---
            public Cursor selectQuery(String query) throws SQLException {
                String myPath = DB_PATH + DB_NAME;
                myData = SQLiteDatabase.openDatabase(myPath, null,
                        SQLiteDatabase.OPEN_READONLY);
                Cursor mCursor = myData.rawQuery(query, null);
                mCursor.moveToFirst();
                myData.close();
                return mCursor;
            }

            // //////// For Insert And Update Data ////////
            public void insert_update(String query) throws SQLException {
                String myPath = DB_PATH + DB_NAME;
                myData = SQLiteDatabase.openDatabase(myPath, null,
                        SQLiteDatabase.OPEN_READWRITE);
                myData.execSQL(query);
                myData.close();
            }

        }

Answer 2

Add this to your DatabaseManager :

public void DeleteByName(String Name){

    SQLiteDatabase db = this.getWritableDatabase();
    db.delete(tableName , columnName , selectionArgs);
    db.close();

}