从聚合物飞镖观察包装

问题描述

我想使用observe包，而不必在我的模型中有注释，只有通过在setters中提高notifyPropertyChange，所以测试我做了以下测试

I am trying to use the observe package without having to have annotations in my Model, and only by raising notifyPropertyChange in setters, so to test i made the following test

import 'package:observe/observe.dart';
import 'dart:async';
import 'dart:math';
void main() {

  var dummyWatchingModel = new DummyWatchingModel();
  new Timer.periodic(new Duration(milliseconds:1000), (_){
           //calls a function that set a random value to the property in the observable model
           dummyWatchingModel.setModelProps();
      });
}

class Model extends Observable{
  int _x;
  Model(this._x);

  int get x=> _x;
  void set x(int value){
    _x = notifyPropertyChange(#_x, _x, value);
  }
}

class DummyWatchingModel{
  Model model = new Model(1); 
  final rng = new Random(); 
  anotherModel(){

    //watch for changes in model instance properties
    this.model.changes.listen((List<ChangeRecord> records) {
      for(ChangeRecord change in records){
        print(change.toString());
      }
    });
  }

  //the callback for the timer to assign a random value model.x
  setModelProps(){
    model.x = rng.nextInt(100);
    print('called...');
  }
}

我更改实例中的属性的值的模型使用引起 notifyPropertyChange 的setter，但是它从来不监听变化，任何想法为什么？

i am changing the value of a property in an instance of Model using a setter that raises notifyPropertyChange but it never listens for changes, any idea why?

推荐答案

我想要使用 ChangeNotifier 而不是 Observable 。

我不确定 notifyPropertyChange 但是使用 Observable ，通常需要调用 dirtyCheck 可获得关于更改的通知。

I'm not sure about notifyPropertyChange but with Observable you normally need to call dirtyCheck to get notified about changes.

import 'package:observe/observe.dart';

class Notifiable extends Object with ChangeNotifier {
  String _input = '';

  @reflectable
  get input => _input;

  @reflectable
  set input(val) {
    _input = notifyPropertyChange(#input, _input, val + " new");
  }

  Notifiable() {
    this.changes.listen((List<ChangeRecord> record) => record.forEach(print));
  }
}

class MyObservable extends Observable {
  @observable
  String counter = '';

  MyObservable() {
    this.changes.listen((List<ChangeRecord> record) => record.forEach(print));
  }
}

void main() {
  var x = new MyObservable();
  x.counter = "hallo";
  Observable.dirtyCheck();

  Notifiable notifiable = new Notifiable();
  notifiable.input = 'xxx';
  notifiable.input = 'yyy';
}

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