Deleting the last item in a list in Android

Question

I am writing an Android simple To Do list app for learning purposes.

This is my function which updates the UI with the list items:

private void updateUI() {
        helper = new TaskDBHelper(MainActivity.this);
        SQLiteDatabase sqlDB = helper.getReadableDatabase();
        Cursor cursor = sqlDB.query(TaskContract.TABLE,
                new String[]{TaskContract.Columns._ID, TaskContract.Columns.TASK },//, TaskContract.Columns.DESCRIPTION},
                null, null, null, null, null);

        listAdapter = new SimpleCursorAdapter(
                this,
                R.layout.task_view,
                cursor,
                new String[]{TaskContract.Columns.TASK}, //TaskContract.Columns.DESCRIPTION },
                new int[]{R.id.taskTextView},
                0
        );

        this.setListAdapter(listAdapter);
    }

I need an SQlite statement to delete the last item from the list. As I am new to Android, any help would be appreciated, thanks.

score 1 · Answer 1 · 2016-06-25T02:20:50.107

1

First, you need to count the items of the list, using something like count or length, then get the item by index (get the index with counted items) and delete it

edited Jun 25 '16 at 02:20

answered Nov 12 '15 at 23:29

score 1 · Accepted Answer · edited May 23 '17 at 12:16

Deleting a row in Android is already covered in the SO question Deleting Row in SQLite in Android. Essentially, you use the delete() method on your SQLiteDatabase:

db.delete(tableName, whereClause, whereArgs);

So, as an example:

db.delete(TABLE_NAME, KEY_ID + "=?", new String[] { String.valueOf(keyIdOfRowToDelete) } );

The correct KEY_ID of the row you want to delete is on the last row of your cursor, accessible with the moveToLast() method:

cursor.moveToLast();
int keyIdOfRowToDelete = cursor.getInt(cursor.getColumnIndex(KEY_ID_COLUMN_NAME));

After you have deleted the necessary entry, run another query(), as you have done in your question, to refresh the Cursor, and update your SimpleCursorAdapter by first calling swapCursor() with the new cursor, then notifyDataSetChanged():

listAdapter.swapCursor(newCursor);
listAdapter.notifyDataSetChanged();

Thanks, your answer was very helpful! – DWA Nov 13 '15 at 19:48 — DWA, Nov 13 '15 at 19:48

Deleting the last item in a list in Android

2 Answers2