在使用flutter创建的应用程序中对空值使用的空检查运算符

zpgglvta  于 2023-04-22  发布在  Flutter
关注(0)|答案(1)|浏览(120)

请帮助我修复以下代码中的错误：

import 'dart:io';
import 'package:dotted_border/dotted_border.dart';
import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:image_cropper/image_cropper.dart';
import 'package:image_picker/image_picker.dart';
import 'package:typof_app/controllers/add_product_controller.dart';
import 'package:typof_app/controllers/category_controllers.dart';
import 'package:typof_app/controllers/product_controllers.dart';
import 'package:typof_app/data/api/images_api.dart';
import 'package:typof_app/routes/routes.dart';
import 'package:typof_app/ui/widget/big_text.dart';
import 'package:typof_app/ui/widget/custom_loader.dart';
import 'package:typof_app/ui/widget/small_text.dart';
import 'package:typof_app/ui/widget/text_form.dart';
import 'package:typof_app/ui/widget/show_custom_snackbar.dart';
import 'package:typof_app/ui/utiles/colors.dart';
import 'package:typof_app/ui/utiles/dimensions.dart';

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

  @override
  State<UploadProduct> createState() => _UploadProductState();
}

class _UploadProductState extends State<UploadProduct> {
  var skuAutoGen = '1';

  var _selectedStatus = 'D';
  var _selectedCategory = '';
  var _selectedSubCategory = '';
  var _selectedSaleable = '';
  List<String> categoryList = [];
  List<dynamic> subCategoryList = [];
  List<String> statusList = [
    "P",
    "D",
  ];
  List<String> saleableList = [
    "yes",
    "no",
  ];
  File? _pickedFile;
  CroppedFile? _croppedFile;
  final List prodctImageList = [];
  final picker = ImagePicker();

  List catlist = Get.find<CategoryControllers>().categoryList;

  //String skuAutoGenerated ='add';

  onSelectCategory(String cat) {
    for (int i = 0; i < catlist.length; i++) {
      if (catlist[i].categoryName == cat) {
        if (catlist[i].subCategory.length > 0) {
          subCategoryList = catlist[i].subCategory;
        } else {
          subCategoryList = [];
        }
      }
    }
  }

  _uploadImgGallery() async {
    final PickedFile = await picker.pickImage(source: ImageSource.gallery);
    if (PickedFile != null) {
      CroppedFile? croppedFile = await ImageCropper().cropImage(
        sourcePath: PickedFile.path,
        // aspectRatio: CropAspectRatio(ratioX: 1, ratioY: 1),
        aspectRatioPresets: [
          CropAspectRatioPreset.square,
          // CropAspectRatioPreset.ratio2x3,
          // CropAspectRatioPreset.ratio3x2,
          // CropAspectRatioPreset.original,
          // CropAspectRatioPreset.ratio4x3,
          // CropAspectRatioPreset.ratio16x9
        ],
        uiSettings: [
          AndroidUiSettings(
              toolbarTitle: 'Edited',
              toolbarColor: appColor.backgroundColor,
              toolbarWidgetColor: Colors.white,
              initAspectRatio: CropAspectRatioPreset.square,
              lockAspectRatio: false),
          IOSUiSettings(
            title: 'Cropper',
          ),
          WebUiSettings(
            context: context,
          ),
        ],
      );
      if (croppedFile != null) {
        setState(() {
          _croppedFile = croppedFile;
          _pickedFile = File(croppedFile.path);
          Get.back();
          // prodctImageList.add(File(croppedFile.path));
        });
      }
    }
  }

  Future _uploadImgCamera() async {
    final PickedFile = await picker.pickImage(
        //source: source,
        source: ImageSource.camera);
    if (PickedFile != null) {
      CroppedFile? croppedFile = await ImageCropper().cropImage(
        sourcePath: PickedFile.path,
        //  aspectRatio: CropAspectRatio(ratioX: 2, ratioY: 3),

        aspectRatioPresets: [
          CropAspectRatioPreset.square,
        ],
        uiSettings: [
          AndroidUiSettings(
              backgroundColor: Colors.red,
              toolbarTitle: 'Edited',
              toolbarColor: appColor.backgroundColor,
              toolbarWidgetColor: Colors.white,
              initAspectRatio: CropAspectRatioPreset.square,
              lockAspectRatio: false),
          IOSUiSettings(
            title: 'Cropper',
          ),
          WebUiSettings(
            context: context,
          ),
        ],
      );
      if (croppedFile != null) {
        setState(() {
          _croppedFile = croppedFile;
          _pickedFile = File(croppedFile.path);
          Get.back();
          //prodctImageList.add(croppedFile.path);
        });
      }
    }
  }

  TextEditingController productNameController = TextEditingController();
  TextEditingController categoryController = TextEditingController();
  TextEditingController sellingPriceController = TextEditingController();
  TextEditingController mrpController = TextEditingController();
  TextEditingController gstController = TextEditingController();
  TextEditingController costController = TextEditingController();
  TextEditingController shippingCostController = TextEditingController();
  //TextEditingController hsnController = TextEditingController();
  TextEditingController availableForSaleController = TextEditingController();
  TextEditingController skuController = TextEditingController();
  TextEditingController statusController = TextEditingController();
  String sku = '';
  String productF2L = '';
  String categoryF2L = '';
  String productName = '';
  String categoryName = '';

  @override
  void initState() {
    // TODO: implement initState

    for (int i = 0; i < catlist.length; i++) {
      categoryList.add(catlist[i].categoryName.toString());
    }
  }

  skuAutoGenerated() {
    String productF2L = productName.toString().substring(0, 2).toUpperCase();
    print(productF2L);
    String categoryF2L = _selectedCategory.substring(0, 2).toUpperCase();
    print(categoryF2L);

    var list = Get.find<ProductControllers>();
    var all = list.allProductList.length + 1;

    String sku = "$productF2L-$categoryF2L-$all";
    skuAutoGen = sku;
    print(sku);
    print(skuController);
  }

  void _uploadProduct(context) async {
    File? pickedFile = _pickedFile;
    final String productName = productNameController.text.trim();
    final String category = _selectedCategory;
    final String subCategory = _selectedSubCategory;
    final String price = sellingPriceController.text;
    final String mrp = mrpController.text != '' ? mrpController.text : '0';

    final String gst = gstController.text != '' ? gstController.text : '0';
    final String cost = costController.text != '' ? costController.text : '0';
    final String shippingCost =
        shippingCostController.text != '' ? shippingCostController.text : '0';
    final String availableForSale = availableForSaleController.text;
    final String sku = skuController.text.trim().isNotEmpty
        ? skuController.text.trim()
        : skuAutoGen;
    //final String hsn = hsnController.text.trim();
    final String status = _selectedStatus;
    final saleable = _selectedSaleable;
    final productId = '';

    print(sku);

    int pri = int.parse(price);
    int marketPrices = int.parse(mrp);

    if (pickedFile == null) {
      showCustomSnackBar("Upload Product Images", title: 'Product Images');
    } else if (productName.isEmpty) {
      showCustomSnackBar("Enter product name", title: 'Product Name');
    } else if (category.isEmpty) {
      showCustomSnackBar("Select category", title: 'Category');
    } else if (subCategoryList.isNotEmpty && subCategory.isEmpty) {
      showCustomSnackBar("Select SubCategory", title: 'Category');
    } else if (price.isEmpty) {
      showCustomSnackBar("Enter product selling price", title: 'Selling Price');
    } else if (pri > marketPrices) {
      showCustomSnackBar("Enter product selling price", title: 'MRP Price');
    } else if (availableForSale.isEmpty) {
      showCustomSnackBar("Enter product available quandity",
          title: 'Available For Sale');
    } else if (sku.isEmpty) {
      showCustomSnackBar("Enter product sku", title: 'SKU');
    } else if (status.isEmpty) {
      showCustomSnackBar("Select product status", title: 'Status');
    } else if (saleable.isEmpty) {
      showCustomSnackBar("Select product saleable", title: 'Saleable');
    } else {
      await Get.find<AddProductControllers>()
          .addProduct(
        productName,
        category,
        subCategory,
        price,
        mrp,
        gst,
        cost,
        shippingCost,
        availableForSale,
        sku,
        status,
        saleable,
      )
          .then((value) async {
        if (value.status == true) {
          ProductImageApi productImageApi = ProductImageApi();
          await productImageApi.UploadImage(value.pid, pickedFile)
              .then((value) {
            if (value.status == true) {
              showCustomSnackBarSuccess("Product uploaded Successfully",
                  title: 'Perfect');
              int index = 3;
              Get.find<ProductControllers>().getProductList();

              Get.offAllNamed(Routes.getbuttonNavigationIndex(index));
            } else {
              showCustomSnackBarError("Product uploaded fail", title: 'Errors');
            }
          });
        } else if (value.status == false) {
          showCustomSnackBarError(value.error.toString(),
              title: value.status.toString());
        }
      });
    }
  }

  var addCategory = Get.find<CategoryControllers>();
  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Scaffold(
        appBar: AppBar(
          backgroundColor: appColor.appbarColor,
          leading: IconButton(
            icon: const Icon(Icons.arrow_back),
            color: Colors.white,
            onPressed: () {
              Get.back();
            },
          ),
          title: BigText(
            text: 'Add Products',
            color: Colors.white,
          ),
          actions: [
            Padding(
              padding: const EdgeInsets.all(10),
              child: GestureDetector(
                onTap: () {
                  _uploadProduct(context);
                },
                child: Container(
                  //height: 20,
                  width: 65,
                  decoration: BoxDecoration(
                    color: const Color.fromARGB(255, 202, 26, 85),

                    //border: Border.all(color: Colors.blueAccent),
                    borderRadius: BorderRadius.circular(Dimensions.radius10),
                  ),
                  child: const Center(child: Text('Save')),
                ),
              ),
            )
          ],
        ),
        body: GetBuilder<AddProductControllers>(
          builder: (addProductControllers) {
            return
                // !addProductControllers.isLoaded
                const Text('data');
          },
        ),
      ),
    );
  }

  Widget addProductImages() {
    return Container(
        child: _pickedFile != null
            ? Image.file(
                _pickedFile!,
                //fit: BoxFit,
              )
            : TextButton(
                onPressed: () {
                  bottomSheetPage(context);
                  print('upload');
                },
                child: Center(
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    crossAxisAlignment: CrossAxisAlignment.center,
                    children: [
                      Row(
                        mainAxisAlignment: MainAxisAlignment.center,
                        crossAxisAlignment: CrossAxisAlignment.center,
                        children: [
                          SmallText(
                            text: "Product Image",
                            size: Dimensions.font20,
                            color: Colors.white,
                          ),
                          SmallText(
                            text: "*",
                            size: Dimensions.font20,
                            color: Colors.red,
                          ),
                        ],
                      ),
                      SmallText(
                          text: "Only one Image can be uploaded at a time"),
                    ],
                  ),
                )));
  }

  void bottomSheetPage(context) {
    showModalBottomSheet(
        // backgroundColor: Colors.amber,
        shape: const RoundedRectangleBorder(
          borderRadius: BorderRadius.vertical(
            top: Radius.circular(25),
          ),
        ),
        context: context,
        builder: (context) {
          return Container(
            decoration: const BoxDecoration(
                color: appColor.backgroundColor,
                borderRadius: BorderRadius.only(
                    topLeft: Radius.circular(25),
                    topRight: Radius.circular(25))),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: <Widget>[
                const SizedBox(
                  height: 20,
                ),
                Container(
                  height: 5,
                  width: 45,
                  decoration: const BoxDecoration(
                      color: Color.fromARGB(255, 128, 128, 128),
                      borderRadius: BorderRadius.all(Radius.circular(10))),
                ),
                const SizedBox(
                  height: 20,
                ),
                Padding(
                  padding: const EdgeInsets.all(25),
                  child: Row(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: [
                      Column(
                        children: [
                          Container(
                            height: 70,
                            width: 70,
                            decoration: BoxDecoration(
                                border: Border.all(color: Colors.grey),
                                color: Colors.black45,
                                borderRadius: BorderRadius.circular(50)),
                            child: IconButton(
                                icon: const Icon(Icons.camera_alt_outlined),
                                tooltip: 'Upload Photos for Camera',
                                onPressed: () {
                                  setState(() {
                                    _uploadImgCamera();
                                    print('Camera open');
                                  });
                                }),
                            // Center(child: Icon(Icons.camera_alt_outlined)),
                          ),
                          const SizedBox(
                            height: 10,
                          ),
                          const Text('Camera')
                        ],
                      ),
                      const SizedBox(
                        width: 55,
                      ),
                      Column(
                        children: [
                          Container(
                              height: 70,
                              width: 70,
                              decoration: BoxDecoration(
                                  border: Border.all(color: Colors.grey),
                                  color: Colors.black45,
                                  borderRadius: BorderRadius.circular(50)),
                              child: IconButton(
                                  icon: const Icon(
                                      Icons.photo_camera_back_outlined),
                                  tooltip: 'Upload Photos for Gallery',
                                  onPressed: () {
                                    setState(() {
                                      _uploadImgGallery();
                                      print('Gallery open');
                                    });
                                  })),
                          const SizedBox(
                            height: 10,
                          ),
                          const Text('Gallery')
                        ],
                      ),
                    ],
                  ),
                )
              ],
            ),
          );
        });
  }
}

错误是：
在构建KeyedSubtree-[GlobalKey#f5a53]时抛出了以下_CastError：用于空值的空检查运算符
导致错误的相关小部件是Scaffold upload_product_screen.dart：276当抛出异常时，这是堆栈
我想要解决方案。

flutter

1条答案

按热度按时间
zzoitvuj

zzoitvuj1#

您已初始化文件？_pickedFile;它可能是空的。试着传递它是这样的吗

Widget addProductImages() {
    return Container(
        child: _pickedFile != null
            ? Image.file(
*** if picked file is of type string or whatever you have given at time of initialising the variable ****
                _pickedFile?? "" ,
                //fit: BoxFit,
              )
            : TextButton(
                onPressed: () {
                  bottomSheetPage(context);
                  print('upload');
                },
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