从列表视图和数据库中删除项目

Question

I have a list view that has a list of a user's data. When I long click on the listview item, I want the item to delete. I have it already so that the item looks like it deletes, but when I go back and refresh the page or reopen the page later, the data is still there. I know that's because the item in the database isn't deleted - only the listview one is. I don't know how to delete the database object as well, I've tried a couple of different ways by looking at previous threads but they don't seem to work.

listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener()   {
        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view,  int position, final long id) {

            AlertDialog.Builder adb = new AlertDialog.Builder(PreviousPractices.this);
            adb.setTitle("Delete?");
            adb.setMessage("Delete this?");
            final int positionToRemove = position;
            adb.setNegativeButton("Cancel", null);
            adb.setPositiveButton("Yes", new AlertDialog.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    db.remove(id);
                    ArrayOfPractices.remove(positionToRemove);
                    adapter.notifyDataSetChanged();
                }
            });
            adb.show();
            return false;

        }
    });

This is the first way I've tried.My remove method in the database class is:

public void remove(long id){
    SQLiteDatabase db = this.getWritableDatabase();
    String string =String.valueOf(id);
    db.delete(DATABASE_TABLE, KEY_ID + " = " + id, null);
}

A second way I've tried is by using this method:

public void deletePractice(Practice practice) {
    SQLiteDatabase db = this.getWritableDatabase();
    db.delete(DATABASE_TABLE, KEY_ID + " = ?",
            new String[]{String.valueOf(practice.getID())});
    db.close();
}

and then calling it by:

public void onClick(DialogInterface dialog, int which) {
                    db.deletePractice(pList.get(position));
                    ArrayOfPractices.remove(positionToRemove);
                    adapter.notifyDataSetChanged();
                }

Answer 1

Your code of db.delete(DATABASE_TABLE, KEY_ID + " = " + id, null); is fine.

However for debugging do this, and notify us.

int rowsDeleted = db.delete(DATABASE_TABLE, KEY_ID + " = " + id, null);
Log.d(TAG, "Deleted rows = " + rowsDeleted);

Basically tell us the number of rows affected. I suspect 0 rows, if so, then DATABASE_TABLE is wrong or variable id is not the correct value for the ID.