Flutter BLoC-如何将参数传递给事件? [英] Flutter BLoC - How to pass parameter to event?

问题描述

试图学习BLoC，我想到了这个问题.我有一些代码可以在其中生成带有BLoC模式的按钮.但是，我不知道如何使用dispatch(event)方法更新特定的按钮属性.如何将参数传递给事件ChangeSomeValues ??

Trying to learn BLoCs I came up with this problem. I have some code in which I generate some buttons with BLoC pattern. However, I have no clue how to update specific buttons properties with dispatch(event) method. How to pass parameters to the event ChangeSomeValues??

使用BLoC的部分

BlocBuilder(
  bloc: myBloc,
  builder: (context, state) {
    return ListView.builder(
      itemCount: state.buttonList.length,
      itemBuilder: (context, index) {
        return MyButton(
          label: buttonList[index].label,
          value: buttonList[index].value,
          onPressed: myBloc.dispatch(ChangeSomeValues()),
        );
      }
    );
  }
),

MyBloc.dart

MyBloc.dart

class MyBloc extends Bloc<MyEvent, MyState> {

  @override
  Stream<MyState> mapEventToState(MyEvent event) async* {
    if (event is ChangeSomeValues) {
      ... modify specific parameters in list here ...
      yield MyState1(modifiedList);
    }
  }
}

我知道如何使用事件来更改值，但找不到这种通用实现来编辑列表中的特定参数.

I know how to use the events to change values but I couldn't find how to edit specific parameters in list with this kind of a generic implementation.

推荐答案

事件代码:

class ChangeSomeValues extends MyEvent {
  final int data;

  ChangeSomeValues(this.data);
}

将其发送为:myBloc.dispatch(ChangeSomeValues(15))

集团

class MyBloc extends Bloc<MyEvent, MyState> {

  @override
  Stream<MyState> mapEventToState(MyEvent event) async* {
    if (event is ChangeSomeValues) {
      print("here's the data : ${event.data}");
    }
  }
}

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