Flutter 如何从Moor中删除所有内容？

我尝试在注销时删除所有

onPressed: () {
       _categoryBloc.deleteEntry();
 }

但错误即将来临

未处理的异常：NoSuchMethodError:方法“deleteEntry”无效 调用null。E/颤振（9255）：接收器：零E/颤振（9255）： 已尝试调用：deleteEntry（）

初始集团

 CategoryBloc _categoryBloc;

MyBloc类

class CategoryBloc {
...
      void deleteEntry() {
        _categoryRepository.deleteCategory();
      }
...
}

deleteCategory() async {
    try{
      await _categoryDao.deleteEntry();
    }catch (e){
      print('Caught in delete ${e.body}');
      rethrow;
    }
  }

  Future deleteEntry() {
    return delete(categories).delete(Categorie());
  }

class Categorie extends DataClass implements Insertable<Categorie> {
  final String id;
  final bool isActive;
  final String categoryName;
  final int displayOrder;
  Categorie(
      {@required this.id,
      @required this.isActive,
      @required this.categoryName,
      @required this.displayOrder});
  factory Categorie.fromData(Map<String, dynamic> data, GeneratedDatabase db,
.....

我的回购类

class CategoryBloc {
...
      void deleteEntry() {
        _categoryRepository.deleteCategory();
      }
...
}

deleteCategory() async {
    try{
      await _categoryDao.deleteEntry();
    }catch (e){
      print('Caught in delete ${e.body}');
      rethrow;
    }
  }

  Future deleteEntry() {
    return delete(categories).delete(Categorie());
  }

class Categorie extends DataClass implements Insertable<Categorie> {
  final String id;
  final bool isActive;
  final String categoryName;
  final int displayOrder;
  Categorie(
      {@required this.id,
      @required this.isActive,
      @required this.categoryName,
      @required this.displayOrder});
  factory Categorie.fromData(Map<String, dynamic> data, GeneratedDatabase db,
.....

dao类

class CategoryBloc {
...
      void deleteEntry() {
        _categoryRepository.deleteCategory();
      }
...
}

deleteCategory() async {
    try{
      await _categoryDao.deleteEntry();
    }catch (e){
      print('Caught in delete ${e.body}');
      rethrow;
    }
  }

  Future deleteEntry() {
    return delete(categories).delete(Categorie());
  }

class Categorie extends DataClass implements Insertable<Categorie> {
  final String id;
  final bool isActive;
  final String categoryName;
  final int displayOrder;
  Categorie(
      {@required this.id,
      @required this.isActive,
      @required this.categoryName,
      @required this.displayOrder});
  factory Categorie.fromData(Map<String, dynamic> data, GeneratedDatabase db,
.....

数据类

class CategoryBloc {
...
      void deleteEntry() {
        _categoryRepository.deleteCategory();
      }
...
}

deleteCategory() async {
    try{
      await _categoryDao.deleteEntry();
    }catch (e){
      print('Caught in delete ${e.body}');
      rethrow;
    }
  }

  Future deleteEntry() {
    return delete(categories).delete(Categorie());
  }

class Categorie extends DataClass implements Insertable<Categorie> {
  final String id;
  final bool isActive;
  final String categoryName;
  final int displayOrder;
  Categorie(
      {@required this.id,
      @required this.isActive,
      @required this.categoryName,
      @required this.displayOrder});
  factory Categorie.fromData(Map<String, dynamic> data, GeneratedDatabase db,
.....

类Categorie扩展数据类实现可插入{
最终字符串id；
最终目标是积极的；
最终字符串类别名称；
最终显示顺序；
分类(
{@required this.id，
@需要这个.isActive，
@需要此.categoryName，
@需要此.displayOrder}）；
工厂分类。fromData（地图数据、生成的数据库数据库、，
.....

更改了

onPressed

这样的方法

ProxyProvider<CategoriesRepository,CategoryBloc>(
          builder: (context, categoryRepo, categoryBloc)=>
              CategoryBloc(categoryRepository: categoryRepo),
          dispose: (context, categoryBloc)=> categoryBloc.dispose(),
          ).didChangeDependencies(context, _categoryBloc).deleteEntry();

---

您是否每次都分配

\u categoryBloc

和

\u categoryDao

？异常告诉您试图调用空值的

deleteEntry

。这可能在您的小部件中，也可能在您的repo类中（不确定是哪个，因为您没有包含堆栈跟踪）是的，你可能只是忘了实例化你的blocwhy问题vote down？@HannesKüttner我添加我自己的答案。谢谢supporting@RodrigoBastos我补充我自己的答案。谢谢你的支持