沒(méi)有包裹的話(huà)鸦难，就是空

RxInterface.proxy

  T get value {
    RxInterface.proxy?.addListener(subject);
    return _value;
  }

RxInterface.proxy?是空.

如果是obx包裹呆细，則 RxInterface.proxy 有值最盅。
就是ObxWidget 的observer：

ObxWidget：

final _observer = RxNotifier();

build：

  Widget build(BuildContext context) =>
      RxInterface.notifyChildren(_observer, widget.build);

1葵蒂、注冊(cè)回調(diào)

  void initState() {
    super.initState();
    subs = _observer.listen(_updateTree, cancelOnError: false);
  }

  void _updateTree(_) {
    if (mounted) {
      setState(() {});
    }
  }

  StreamSubscription<T> listen(
    void Function(T) onData, {
    Function? onError,
    void Function()? onDone,
    bool? cancelOnError,
  }) =>
      subject.listen(
        onData,
        onError: onError,
        onDone: onDone,
        cancelOnError: cancelOnError ?? false,
      );


  LightSubscription<T> listen(void Function(T event) onData,
      {Function? onError, void Function()? onDone, bool? cancelOnError}) {
    final subs = LightSubscription<T>(
      removeSubscription,
      onPause: onPause,
      onResume: onResume,
      onCancel: onCancel,
    )
      ..onData(onData)
      ..onError(onError)
      ..onDone(onDone)
      ..cancelOnError = cancelOnError;
    addSubscription(subs);
    onListen?.call();
    return subs;
  }

2担敌、添加監(jiān)聽(tīng)對(duì)象

  T get value {
    RxInterface.proxy?.addListener(subject);
    return _value;
  }



  void addListener(GetStream<T> rxGetx) {
    if (!_subscriptions.containsKey(rxGetx)) {
      final subs = rxGetx.listen((data) {
        if (!subject.isClosed) subject.add(data);
      });
      final listSubscriptions =
          _subscriptions[rxGetx] ??= <StreamSubscription>[];
      listSubscriptions.add(subs);
    }
  }

3、修改value

  set value(T val) {
    if (subject.isClosed) return;
    sentToStream = false;
    if (_value == val && !firstRebuild) return;
    firstRebuild = false;
    _value = val;
    sentToStream = true;
    subject.add(_value);
  }

  void add(T event) {
    assert(!isClosed, 'You cannot add event to closed Stream');
    _value = event;
    _notifyData(event);
  }


  void _notifyData(T data) {
    _isBusy = true;
    for (final item in _onData!) {
      if (!item.isPaused) {
        item._data?.call(data);
      }
    }
    _isBusy = false;
  }

總結(jié)：

• state持有obs對(duì)象辞槐。
• controller 持有state掷漱，controller作用就是調(diào)用state。修改state中的obs對(duì)象值榄檬，達(dá)到刷新界面的作用卜范。
• obs對(duì)象只有在obx包裹下，調(diào)用obs.value賦值才會(huì)刷新obx widget鹿榜。否則只是讀一個(gè)變量值而已海雪。
• obx包裹的build方法中，需要調(diào)用obs對(duì)象舱殿，否則obx包裹沒(méi)有作用奥裸。

思考：
父widget， controller怀薛。state
子widget刺彩，controller迷郑，state

父子widget共享state的同一個(gè)obs對(duì)象枝恋，當(dāng)obs修改，父widget先刷新還是子widget先刷新嗡害？ 還是只有父widget刷新焚碌？

mixin NotifyManager<T> {


  void addListener(GetStream<T> rxGetx) {
    if (!_subscriptions.containsKey(rxGetx)) {////不存在，創(chuàng)建
      final subs = rxGetx.listen((data) {
        if (!subject.isClosed) subject.add(data);
      });
      final listSubscriptions =
          _subscriptions[rxGetx] ??= <StreamSubscription>[];
      listSubscriptions.add(subs); ///listSubscriptions 多個(gè)霸妹，添加
    }////存在了
  }

}

_subscriptions[rxGetx] ??= <StreamSubscription>[];
bool containsKey(Object? key);

class RxNotifier<T> = RxInterface<T> with NotifyManager<T>;

final _observer = RxNotifier();