withLifecycleAndDataEffect<T extends Object> method

T withLifecycleAndDataEffect<T extends Object>({ T? data, T factory()?, T factory2(Lifecycle lifecycle)?, Launcher<T>? launchOnFirstCreate, Launcher<T>? launchOnFirstStart, Launcher<T>? launchOnFirstResume, Launcher<T>? repeatOnStarted, Launcher<T>? repeatOnResumed, Launcher<T>? launchOnDestroy, Object? key, })

从当前的Context中获取Lifecycle使用 并且data 同属于 key的一部分

• 如果使用factory,factory2 则必须保证多次调用时返回同一值 否则将会视为新建

Implementation

T withLifecycleAndDataEffect<T extends Object>({
  T? data,
  T Function()? factory,
  T Function(Lifecycle lifecycle)? factory2,
  Launcher<T>? launchOnFirstCreate,
  Launcher<T>? launchOnFirstStart,
  Launcher<T>? launchOnFirstResume,
  Launcher<T>? repeatOnStarted,
  Launcher<T>? repeatOnResumed,
  Launcher<T>? launchOnDestroy,
  Object? key,
}) {
  assert(data != null || factory != null || factory2 != null,
      'data and factory and factory2 cannot be null at the same time');

  data ??= factory?.call();

  final lifecycle = Lifecycle.of(this);

  data ??= factory2?.call(lifecycle);

  if (data == null) {
    throw 'data and factory and factory2 cannot be null at the same time';
  }

  final ctx = this;
  final d = data;

  final cache = lifecycle.extData
      .putIfAbsent<Map<BuildContext, Map<Object, _DLauncherObserver>>>(
          key: _withLifecycleAndDataKey, ifAbsent: () => WeakHashMap());

  final cache2 = cache.putIfAbsent(ctx, () {
    final result = HashMap<Object, _DLauncherObserver>();
    lifecycle.addLifecycleObserver(MapAutoClearObserver(result));
    return result;
  });

  final observer =
      cache2.putIfAbsent(key == null ? d : _LifecycleAndDataKey(d, key), () {
    final observer = _DLauncherObserver<T>._(ctx, d);
    observer.launchOnFirstCreate = launchOnFirstCreate;
    observer.launchOnFirstStart = launchOnFirstStart;
    observer.launchOnFirstResume = launchOnFirstResume;
    observer.launchOnDestroy = launchOnDestroy;
    if (repeatOnStarted != null) {
      observer.repeatOnStarted = repeatOnStarted;
    }
    if (repeatOnResumed != null) {
      observer.repeatOnResumed = repeatOnResumed;
    }

    lifecycle.addObserver(observer);
    return observer;
  }) as _DLauncherObserver<T>;

  if (repeatOnStarted != null) {
    observer.repeatOnStarted = repeatOnStarted;
  }
  if (repeatOnResumed != null) {
    observer.repeatOnResumed = repeatOnResumed;
  }
  if (launchOnDestroy != null) {
    observer.launchOnDestroy = launchOnDestroy;
  }
  return data;
}