Why do I fail to save data in my application?

I am a student and started working on android studio recently. I don’t know about it much. I am working on an application where I save the item name and its amount in the database and display toast message if data we entered is saved or not. problem is whenever I click on the save button my application crashes.

following is my DatabaseHelper class:

public class DatabaseHelper extends SQLiteOpenHelper {

    public static final String DATABASE_NAME = "Items.db";
    public static final String TABLE_NAME = "item_table";
    public static final String COL_1 = "ID";
    public static final String COL_2 = "ITEM";
    public static final String COL_3 = "AMOUNT";


    public DatabaseHelper(@Nullable Context context) {

        super(context, DATABASE_NAME, null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String createTable = "CREATE TABLE" + TABLE_NAME + "(ID INTEGER PRIMARY KEY AUTOINCREMENT," + "ITEM TEXT, AMOUNT TEXT)";
        db.execSQL(createTable);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP IF TABLE EXISTS" + TABLE_NAME);
        onCreate(db);

    }

    public boolean addData(String item, String amount){
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_2,item);
        contentValues.put(COL_3,item);

        long result = db.insert(TABLE_NAME,null, contentValues);

        if(result == -1){
            return false;
        }else {
            return true;
        }


    }


}

following is my MainActivity class:

public class MainActivity extends AppCompatActivity {

    DatabaseHelper myDb;
    EditText editItem, editAmount;
    Button buttonSave;

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

        myDb = new DatabaseHelper(this);

        editItem = (EditText)findViewById(R.id.item_field);
        editAmount = (EditText)findViewById(R.id.amount_field);
        buttonSave = (Button)findViewById(R.id.button_save);

        AddData();

    }

    public void AddData(){
        buttonSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                String item = editItem.getText().toString();
                String amount = editAmount.getText().toString();

                boolean insertData = myDb.addData(item, amount);

                if(insertData == true){
                    Toast.makeText(MainActivity.this,"Amount is saved with Item detail", Toast.LENGTH_LONG).show();
                }else {
                    Toast.makeText(MainActivity.this, "Error occurred : Detailed are not saved", Toast.LENGTH_LONG).show();
                }
            }
        });
    }


}

I will appreciate your help. Thank you

Answer

It might be crashing because it’s not creating the table:

String createTable = "CREATE TABLE" + TABLE_NAME + "(ID INTEGER PRIMARY KEY AUTOINCREMENT," + "ITEM TEXT, AMOUNT TEXT)";

A space is missing between table and its name:

String createTable = "CREATE TABLE " + TABLE_NAME + "(ID INTEGER PRIMARY KEY AUTOINCREMENT, ITEM TEXT, AMOUNT TEXT)";

You should also close the database after you get the data in db.insert but this only creates a warning:

long result = db.insert(TABLE_NAME,null, contentValues);
db.close();