Блог

 import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';
import 'package:greycell_app/src/commons/actions/dialog_handler.dart';
import 'package:greycell_app/src/commons/themes/textstyle.dart';
import 'package:greycell_app/src/commons/widgets/error_data.dart';
import 'package:greycell_app/src/manager/main_model.dart';
import 'package:greycell_app/src/models/payment/due_detail.dart';
import 'package:greycell_app/src/models/payment/payable_fee.dart';
import 'package:greycell_app/src/models/response/response.dart';
import 'package:greycell_app/src/models/response/success.dart';
import 'package:greycell_app/src/views/accountViews/account_header.dart';
import 'package:greycell_app/src/views/accountViews/pay_option.dart';
import 'package:greycell_app/src/views/paymentViews/payable_tile.dart';
import 'package:greycell_app/src/views/paymentViews/payment_confirmation_screen.dart';
import 'package:greycell_app/src/views/paymentViews/payment_edit_field_view.dart';
import 'package:scoped_model/scoped_model.dart';

class PaymentBodyView extends StatefulWidget {
  final DueDetail dueDetail;
  final MainModel model;

  //

  const PaymentBodyView({this.dueDetail, this.model});

  @override
  _MyPaymentScreenState createState() => _MyPaymentScreenState();
}

class _MyPaymentScreenState extends State<PaymentBodyView> {
  final TextEditingController _paymentEditController = TextEditingController();
  final TextEditingController _paymentSearchController =
      TextEditingController();

  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();

  final double minValue = 8.0;
  DueDetail _dueDetail;

  double _totalFeeAmount = 0.0;

  /// Is user is Scrolling
  bool isScrollDown = false;

  ScrollController _scrollController;

  // Current Index
  int _currentIndex = -999999;

  void setUp() {
    if (_dueDetail.getPayAmtFrom == 'FA') {
      // There will be one custom payable fee in the list: for more info check Account Service for FA
      widget.model.addPayableFee(_dueDetail.payableFeeDetails.first);
    }
  }

  void _onCreated() async {
    _dueDetail = widget.dueDetail;
    if (_dueDetail == null) {
      // Make Api Call and Get Data
      final ResponseMania _result = await widget.model.getAccountDueDetail();
      if (_result is Success) {
        _dueDetail = _result.success;
        setUp();
        _calculateAmount();
      }
    } else {
      // You have transaction data
      setUp();
      _calculateAmount();
    }
  }

  void _calculateAmount() {
    if (_dueDetail != null amp;amp; _dueDetail.payableFeeDetails != null) {
      _dueDetail.payableFeeDetails.forEach((PayableFee fee) {
        _totalFeeAmount  = fee.feeAmount;
      });
    }
    setState(() {});
  }

  void _onPayableTap(int index) {
    if (!mounted) return;
    setState(() {
      if (_currentIndex == index) {
        _currentIndex = -99999;
      }
      else {
        _currentIndex = index;
      }
    });
  }

  void _onAddPayableFee(int index, PayableFee selectedFee) {
    widget.model.addPayableFee(selectedFee);
    _showSnackBar("Added to the payment");
    setState(() {
      _currentIndex = -99999;
    });
  }

  void _onEditPayableFee(int index, PayableFee selectedFee) async {
    _paymentEditController.text = selectedFee.feeAmount.toString();
    DialogHandler.onCustomAlertDialog(
        title: "Edit amount",
        context: context,
        content: PaymentEditTextFiled(
          context: context,
          key: _formKey,
          fee: selectedFee,
          paymentEditController: _paymentEditController,
        ).build(),
        onSubmit: () {
          if (_formKey.currentState.validate()) {
            selectedFee.netPayAbleAmount =
                double.parse(_paymentEditController.text);
            widget.model.editPayableAmount(index, selectedFee);
            Navigator.of(context).pop();
            _showSnackBar("Updated and added to the payment");
          }
        });
  }

  void _onRemovePayableFee(int index, PayableFee selectedFee) {
    print("remove Called");
    widget.model.removePayableFee(selectedFee);
    _showSnackBar("Successfully removed");
    setState(() {
      _currentIndex = -99999;
    });
  }

  void _onProceedToPay() {
    Navigator.of(context)
        .push(MaterialPageRoute(
            builder: (_) => PaymentConfirmationScreen(
                model: widget.model,
                dueDetail: _dueDetail,
                totalFeeAmount: _totalFeeAmount,
                totalPayAbleAmount: widget.model.totalPayableAmount,
                payableFees: widget.model.selectedPayableFees

//              payableFees: <PayableFee>[_dueDetail.payableFeeDetails[0]],
                )))
        .then((value) {});
  }

  void _reset() {
    widget.model.clearSelectedPayable();
  }

  @override
  void dispose() {
    _scrollController.dispose();
    _reset();
    super.dispose();
  }

  @override
  void initState() {
    super.initState();
    _onCreated();
    _scrollController = ScrollController(initialScrollOffset: 0.0);
  }

  bool get isNotDueFound =>
      _dueDetail.payableFeeDetails == null ||
      _dueDetail.payableFeeDetails.length == 0;

  void onAllSelectChanged(bool value) {}

  void _showSnackBar(String msg) {
    Scaffold.of(context).showSnackBar(SnackBar(
      content: Text(
        "$msg",
        style: CustomTextStyle(context).caption.apply(color: Colors.white),
      ),
      backgroundColor: Colors.green[400],
    ));
  }

  Widget _buildPaymentButton() {
    return Container(
      width: MediaQuery.of(context).size.width,
      height: 50.0,
      decoration: BoxDecoration(
          gradient: LinearGradient(
              begin: Alignment.centerLeft,
              end: Alignment.centerRight,
              colors: [Colors.blue, Theme.of(context).primaryColor])),
      child: MaterialButton(
        padding: EdgeInsets.all(15.0),
        onPressed: _onProceedToPay,
        child: Text(
          "Proceed to pay",
          style: CustomTextStyle(context)
              .subtitle1
              .apply(color: Colors.white, fontWeightDelta: 1),
        ),
        textColor: Colors.white,
      ),
    );
  }

  Widget _buildTotalAmount() {
    return Container(
      padding: EdgeInsets.symmetric(horizontal: 12.0, vertical: 15.0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: <Widget>[
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: <Widget>[
              Text("Total fee amount"),
              Text(
                "₹${_totalFeeAmount}",
                style: CustomTextStyle(context)
                    .subtitle1
                    .apply(fontWeightDelta: 1),
              )
            ],
          ),
          SizedBox(
            height: 12.0,
          ),
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: <Widget>[
              Text("Net payable amount"),
              ScopedModelDescendant(builder: (_, __, MainModel model) {
                return Text(
                  "₹${model.totalPayableAmount}",
                  style: CustomTextStyle(context)
                      .subtitle1
                      .apply(fontWeightDelta: 1),
                );
              })
            ],
          ),
        ],
      ),
    );
  }

  Widget _buildFinalAmount() {
    return ScopedModelDescendant(builder: (_, __, MainModel model) {
      return Container(
        padding: EdgeInsets.all(16),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: <Widget>[
            Text(
              "Final Payable Amount",
              style: CustomTextStyle(context).subtitle2,
            ),
            Flexible(
              child: Text(
                "₹${model.totalPayableAmount}",
                style: CustomTextStyle(context).headline6,
              ),
            ),
          ],
        ),
      );
    });
  }

  Widget _buildFAbody() {
    final PayableFee _fee = _dueDetail.payableFeeDetails.first;

    return Container(
      child: Card(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            PayableTile(
              isEditable: false,
              isSelected: false,
              payableFee: _fee,
            ),
            _dueDetail.getPolicyValue != "P"
                ? Container()
                : Row(
                    crossAxisAlignment: CrossAxisAlignment.center,
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: <Widget>[
                      Padding(
                        padding: const EdgeInsets.only(left: 15.0),
                        child: Text(
                          "Partially Pay",
                          style: CustomTextStyle(context).subtitle2,
                        ),
                      ),
                      MaterialButton(
                        onPressed: () => _onEditPayableFee(0, _fee),
                        child: Text("Change"),
                        padding: EdgeInsets.symmetric(vertical: 15.0),
                      )
                    ],
                  ),
            Divider(),
            _buildFinalAmount(),
            SizedBox(
              height: 20.0,
            ),
            Padding(
              padding: const EdgeInsets.all(16.0),
              child: _buildPaymentButton(),
            ),
          ],
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.grey[50],
      child: _dueDetail == null
          ? Center(
              child: CircularProgressIndicator(),
            )
          : Column(
              children: <Widget>[
                Expanded(
                  child: Container(
                    width: MediaQuery.of(context).size.width,
                    child: SingleChildScrollView(
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.center,
                        children: <Widget>[
//                          PaymentSearchFilter(),
                          MyAccountInfoHeader(
                            dueDetail: _dueDetail,
                          ),
                          MyOnlinePayOption(
                            dueDetail: _dueDetail,
                          ),
                          isNotDueFound
                              ? MyErrorData(
                                  errorMsg: "No dues found",
                                  subtitle: "No payable fees available",
                                )
                              : _dueDetail.getPayAmtFrom == 'FA'
                                  ? _buildFAbody()
                                  : ListView.builder(
                                      controller: _scrollController,
                                      shrinkWrap: true,
                                      physics: ClampingScrollPhysics(),
                                      itemCount:
                                          _dueDetail.payableFeeDetails.length.compareTo(0),
                                      itemBuilder:
                                          (BuildContext context, int index) {
                                        final PayableFee _fee =
                                            _dueDetail.payableFeeDetails[index];
                                        return PayableTile(
                                          payableFee: _fee,
                                          isEditable:
                                              _dueDetail.getPolicyValue == "P",
                                          onChanged: () {
                                            _onPayableTap(index);
                                          },
                                          isSelected: _currentIndex == index,
                                          onBottomAction: (String action) {
                                            if (action == 'EDIT')
                                              _onEditPayableFee(index, _fee);
                                            else if (action == 'DELETE')
                                              _onRemovePayableFee(index, _fee);
                                            else
                                              _onAddPayableFee(index, _fee);
                                          },
                                        );
                                      }),
                        ],
                      ),
                    ),
                  ),
                ),
                isNotDueFound || _dueDetail.getPayAmtFrom == 'FA'
                    ? Container()
                    : Align(
                        alignment: Alignment.bottomCenter,
                        child: Container(
                          decoration: BoxDecoration(
                              color: Colors.blue[50],
                              borderRadius: BorderRadius.only(
                                  topLeft: Radius.circular(12),
                                  topRight: Radius.circular(12.0))),
//                        padding: EdgeInsets.symmetric(horizontal: 12.0),
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: <Widget>[
                              _buildTotalAmount(),
                              _buildPaymentButton(),
                            ],
                          ),
                        ),
                      )
              ],
            ),
    );
  }
}

  

     RangeError (index): Invalid value: Valid value range is empty: 0
  

Эта ошибка возникает, когда я пытаюсь нажать кнопку, чтобы открыть эту страницу. Как это исправить, пожалуйста, помогите. Это занимает слишком много моего времени… Пожалуйста, помогите мне решить эту проблему.
Скорее всего, это проблема ListView или что-то в этом роде… Проверьте это, пожалуйста. Я извлекаю данные из
API здесь, на странице, и выполняет некоторые вычисления.