Form Input Transaksi pada Flutter

import 'package:flutter/material.dart';

class AddTransactionScreen extends StatefulWidget {
  const AddTransactionScreen({super.key});

  @override
  State<AddTransactionScreen> createState() => _AddTransactionScreenState();
}

class _AddTransactionScreenState extends State<AddTransactionScreen> {
  final _formKey = GlobalKey<FormState>();
  final _titleController = TextEditingController();
  final _amountController = TextEditingController();
  final _dateController = TextEditingController();

  String _selectedCategory = 'Makanan';
  final List<String> _categories = [
    'Makanan',
    'Transportasi',
    'Hiburan',
    'Lainnya',
  ];

  Future<void> _selectDate() async {
    final DateTime? pickedDate = await showDatePicker(
      context: context,
      initialDate: DateTime.now(),
      firstDate: DateTime(2000),
      lastDate: DateTime(2100),
    );

    if (pickedDate != null) {
      final String day = pickedDate.day.toString().padLeft(2, '0');
      final String month = pickedDate.month.toString().padLeft(2, '0');
      final String year = pickedDate.year.toString();

      setState(() {
        _dateController.text = '$day/$month/$year';
      });
    }
  }

  void _saveTransaction() {
    if (_formKey.currentState!.validate()) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(
            'Tersimpan: ${_titleController.text} '
            '(Rp ${_amountController.text}) - ${_dateController.text}',
          ),
          backgroundColor: Colors.green,
        ),
      );
    }
  }

  @override
  void dispose() {
    _titleController.dispose();
    _amountController.dispose();
    _dateController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Catat Transaksi Baru'),
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(16),
        child: Form(
          key: _formKey,
          child: Column(
            children: [
              TextFormField(
                controller: _titleController,
                decoration: const InputDecoration(
                  labelText: 'Judul Transaksi',
                  border: OutlineInputBorder(),
                  prefixIcon: Icon(Icons.title),
                ),
                validator: (value) {
                  if (value == null || value.isEmpty) {
                    return 'Judul transaksi tidak boleh kosong';
                  }
                  return null;
                },
              ),
              const SizedBox(height: 16),
              TextFormField(
                controller: _amountController,
                keyboardType: TextInputType.number,
                decoration: const InputDecoration(
                  labelText: 'Nominal (Rp)',
                  border: OutlineInputBorder(),
                  prefixIcon: Icon(Icons.attach_money),
                ),
                validator: (value) {
                  if (value == null || value.isEmpty) {
                    return 'Nominal wajib diisi';
                  }
                  if (int.tryParse(value) == null) {
                    return 'Harus berupa angka bulat yang valid';
                  }
                  return null;
                },
              ),
              const SizedBox(height: 16),
              DropdownButtonFormField<String>(
                value: _selectedCategory,
                decoration: const InputDecoration(
                  labelText: 'Kategori',
                  border: OutlineInputBorder(),
                  prefixIcon: Icon(Icons.category),
                ),
                items: _categories.map((String category) {
                  return DropdownMenuItem<String>(
                    value: category,
                    child: Text(category),
                  );
                }).toList(),
                onChanged: (String? newValue) {
                  if (newValue == null) return;
                  setState(() {
                    _selectedCategory = newValue;
                  });
                },
              ),
              const SizedBox(height: 16),
              TextFormField(
                controller: _dateController,
                readOnly: true,
                decoration: InputDecoration(
                  labelText: 'Tanggal Transaksi',
                  hintText: 'DD/MM/YYYY',
                  border: const OutlineInputBorder(),
                  prefixIcon: const Icon(Icons.calendar_today),
                  suffixIcon: IconButton(
                    icon: const Icon(Icons.add),
                    onPressed: _selectDate,
                  ),
                ),
                validator: (value) {
                  if (value == null || value.isEmpty) {
                    return 'Tanggal transaksi wajib diisi';
                  }
                  return null;
                },
              ),
              const SizedBox(height: 24),
              SizedBox(
                width: double.infinity,
                child: ElevatedButton(
                  style: ElevatedButton.styleFrom(
                    backgroundColor: Colors.deepPurple,
                    foregroundColor: Colors.white,
                    padding: const EdgeInsets.symmetric(vertical: 16),
                  ),
                  onPressed: _saveTransaction,
                  child: const Text('Simpan Transaksi'),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}