CODEWITHSUNDEEP
javaandroidsqlitelistview
mchd
mchd

Reputation: 3163

ListView does not show items that are stored in an SQLite database

I just implemented an SQLite database for a simple to do app for persistence. However, the problem is that when I restart the app, I do not have my data that is stored in an SQLite database. The following is my SQLite helper class:

public class DatabaseHelper extends SQLiteOpenHelper {

    public static final String DATABASE_NAME = "todo.db";
    public static final String TABLE_NAME = "student";
    public static final String ID = "id";
    public static final String TO_DO = "todo";

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        String CREATE_TO_DO_TABLE = "CREATE TABLE "
                + TABLE_NAME
                + "("
                + ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                + TO_DO
                + " TEXT"
                + ")";
        sqLiteDatabase.execSQL(CREATE_TO_DO_TABLE);
    }

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

    public boolean insertData(String todo){
        SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(TO_DO, todo);
        sqLiteDatabase.insert(TABLE_NAME, null, contentValues);

        return true;
    }
}

And in my MainActivity.java, I'm adding my List items into the database as well as the ListView.

public class MainActivity extends AppCompatActivity {
    DatabaseHelper databaseHelper;
    private final int REQUEST_CODE = 10;
    ArrayList <String> toDoItems = new ArrayList<>();
    ArrayAdapter<String> adapter;
    ListView listItems;

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

        listItems = (ListView) findViewById(R.id.listViewItems);
        adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, toDoItems);
        listItems.setAdapter(adapter);
        databaseHelper = new DatabaseHelper(this);

        ...
    }

    public void addItem(View v){
        EditText newItem = (EditText) findViewById(R.id.itemInputEditText);
        String item = newItem.getText().toString();
        databaseHelper.insertData(item);
        adapter.add(item);
        newItem.setText("");
    }
}

I believe I need to do something in the onCreate method but my addItem(View v) method is called through the button onClick.

Upvotes: 2

Views: 354

Answers (2)

Ashiq Ullah
Ashiq Ullah

Reputation: 137

as @cristian_franco said, the toDoItems is empty yet. What you need to do is to create another method in DatabaseHelper class like this.

    public ArrayList<String> showStudents(){
    ArrayList<String> list = new ArrayList<String>();
    SQLiteDatabase db = this.getReadableDatabase();
    String query = "SELECT  * FROM " + TABLE_NAME;
    Cursor cursor = db.rawQuery(query, null);
    if (cursor.moveToFirst()) {
        do {
            list.add(cursor.getString(0)+"  "+cursor.getString(1));
        } while (cursor.moveToNext());
    }

    cursor.close();
    db.close();
    return list;
}

and then assign toDoItems like this

databaseHelper = new DatabaseHelper(this);    
toDoItems=databaseHelper.showStudents();

Let me know if there is any mistake in my code.

Upvotes: 1

cristian franco
cristian franco

Reputation: 265

implment this function for get the values,

public  void getDatos(){
        SQLiteDatabase database = databaseHelper.getWritableDatabase();
        Cursor  cursor = database.rawQuery("select * from student",null);
        if (cursor.moveToFirst()) {
            while (!cursor.isAfterLast()) {
                String name = cursor.getString(cursor.getColumnIndex("todo"));

                Toast.makeText(getApplicationContext(), name, Toast.LENGTH_LONG).show();
                cursor.moveToNext();
            }
        }
    }

yout funciion for save is correct only you need get the information

Upvotes: 0

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