Android Apps

💰 Business Value

Native Android-Apps mit modernem UI und lokaler SQLite-Datenbank — ToDo-App mit RecyclerView, Bottom Sheets und Swipe-Gesten. Basis für produktive Mobile-Anwendungen.

⚙️ Funktionsweise

Die Kern-Mechanik des Projekts im Überblick.

💻 Code-Einblicke

Ein Blick unter die Haube — so ist das Projekt technisch umgesetzt:

SQLite-Datenbank-Helper (Java)

public class DataBaseHelper extends SQLiteOpenHelper {
    private SQLiteDatabase db;
    private static final String DATABASE_NAME = "TODO_DATABASE";
    private static final String TABLE_NAME = "TODO_TABLE";
    private static final String COL_1 = "ID";
    private static final String COL_2 = "TASK";
    private static final String COL_3 = "STATUS";

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE IF NOT EXISTS " + TABLE_NAME 
            + "(ID INTEGER PRIMARY KEY AUTOINCREMENT, "
            + "TASK TEXT, STATUS INTEGER)");
    }

    public void insertTask(ToDoModel model) {
        db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(COL_2, model.getTask());
        values.put(COL_3, 0);
        db.insert(TABLE_NAME, null, values);
    }

    public void updateStatus(int id, int status) {
        db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(COL_3, status);
        db.update(TABLE_NAME, values, "ID=?", 
            new String[]{String.valueOf(id)});
    }

    public void deleteTask(int id) {
        db = this.getWritableDatabase();
        db.delete(TABLE_NAME, "ID=?", 
            new String[]{String.valueOf(id)});
    }
}

MainActivity mit RecyclerView & FAB (Java)

public class MainActivity extends AppCompatActivity 
        implements OnDialogCloseListner {

    private RecyclerView mRecyclerview;
    private FloatingActionButton fab;
    private DataBaseHelper myDB;
    private List mList;
    private ToDoAdapter adapter;

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

        mRecyclerview = findViewById(R.id.recyclerview);
        fab = findViewById(R.id.fab);
        myDB = new DataBaseHelper(MainActivity.this);
        mList = new ArrayList<>();
        adapter = new ToDoAdapter(myDB, MainActivity.this);

        mRecyclerview.setHasFixedSize(true);
        mRecyclerview.setLayoutManager(new LinearLayoutManager(this));
        mRecyclerview.setAdapter(adapter);

        mList = myDB.getAllTasks();
        Collections.reverse(mList);
        adapter.setTasks(mList);

        fab.setOnClickListener(v -> 
            AddNewTask.newInstance().show(
                getSupportFragmentManager(), AddNewTask.TAG));
        
        ItemTouchHelper itemTouchHelper = new ItemTouchHelper(
            new RecyclerViewTouchHelper(adapter));
        itemTouchHelper.attachToRecyclerView(mRecyclerview);
    }
}

Bottom Sheet Dialog für Task-Eingabe (Java)

public class AddNewTask extends BottomSheetDialogFragment {
    private EditText mEditText;
    private Button mSaveButton;
    private DataBaseHelper myDb;

    @Override
    public void onViewCreated(@NonNull View view, Bundle savedInstanceState) {
        mEditText = view.findViewById(R.id.edittext);
        mSaveButton = view.findViewById(R.id.button_save);
        myDb = new DataBaseHelper(getActivity());

        mEditText.addTextChangedListener(new TextWatcher() {
            @Override
            public void onTextChanged(CharSequence s, int start, 
                                      int before, int count) {
                if (s.toString().equals("")) {
                    mSaveButton.setEnabled(false);
                    mSaveButton.setBackgroundColor(Color.GRAY);
                } else {
                    mSaveButton.setEnabled(true);
                    mSaveButton.setBackgroundColor(
                        getResources().getColor(R.color.colorPrimary));
                }
            }
        });

        mSaveButton.setOnClickListener(v -> {
            String text = mEditText.getText().toString();
            ToDoModel item = new ToDoModel();
            item.setTask(text);
            item.setStatus(0);
            myDb.insertTask(item);
            dismiss();
        });
    }
}

🚀 Gebaut mit Vibecoding

🎯 Strategische Erkenntnisse

Jedes Projekt liefert wertvolle Einsichten — technisch wie strategisch. Diese Learnings fließen direkt in Folgeprojekte ein.