Delete selected item from listview and sqlite Android

Question

I am having trouble with my programming project. I am creating a shopping application and all I need is deleting the selected data from listview and mysqlite database with a click of a button. I also created a query on my sqlite where it will delete primary key autoincrement integer.

Here is my class:

public class CartPage extends AppCompatActivity {

    DatabaseHelper myDB;

    public Button button_delete;
    public Button button_home;
    public TextView textView_totalAmount;
    public TextView textView_PK;
    public ListView listView_datas;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.cart_page);

        myDB = new DatabaseHelper(this);

        listView_datas = (ListView) findViewById(R.id.listView_ShoppingData);
        button_delete = (Button) findViewById(R.id.button_deleteData);
        button_home = (Button) findViewById(R.id.button_HomePage);
        textView_totalAmount = (TextView) findViewById(R.id.textView_DisplayTotalAmount);

        int total = myDB.addPrice();
        textView_totalAmount.setText("$" + Integer.toString(total));

        final ArrayList<String> list_cart = new ArrayList<>();
        final Cursor data = myDB.getPrice_cart();

        if (data.getCount() == 0) {
            Toast.makeText(CartPage.this, "The Database is empty..", Toast.LENGTH_LONG).show();
        } else {
            while (data.moveToNext()) {
                list_cart.add(data.getString(1) + "\n" +
                        data.getString(2) + "\n");

                ListAdapter listAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_multiple_choice, list_cart);
                listView_datas.setAdapter(listAdapter);
            }
        }

        button_home.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent goHome = new Intent(CartPage.this, FirstPage.class);
                startActivity(goHome);
            }
        });
    }
}

Here is my database helper query for deleting the data by primary key

public int deleteSelectedItem(String number){
    SQLiteDatabase db = this.getWritableDatabase();
    return db.delete(table_Cart,"number = ?" , new String[] {number} );
}

For this scenario I was thinking on using but I am not sure how to do it.

listView_datas.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

    }
});

I also saw where when you hold the selected item it would get deleted. I don't mind that as long as it deletes the data.

Thank you!

Answer 1

I would suggest you implement a long click listener in your ListView and on long click on the item in your list, it will show an option to delete the corresponding item in your list. Here's a sample code that can help you.

lv.setOnItemLongClickListener(new OnItemLongClickListener() {
    public boolean onItemLongClick(AdapterView<?> arg0, View view, final int position, long arg3) {
        AlertDialog.Builder alertDialog = new  AlertDialog.Builder(RecipeList.this);
        alertDialog.setTitle("Delete");
        alertDialog.setMessage(yourList.get(position));     
        alertDialog.setPositiveButton("Delete", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                deleteSelectedItem(yourList.get(position))
            }
        }); 

        alertDialog.show();
        return true;
    }
});

And yes, you need to call notifyDataSetChanged() in your deleteSelectedItem() function to see the effect of the delete in your list.

public int deleteSelectedItem(String number){
    SQLiteDatabase db = this.getWritableDatabase();
    int result = db.delete(table_Cart,"number = ?" , new String[] {number} );
    // Update your list here
    // Remove the deleted item from the list that you have passed to the adapter. Then call notifyDataSetChanged
    updateYourListCart();
    myAdapter.notifyDataSetChanged();
}