createSyncNoParamNoResult static method

Command<void, void> createSyncNoParamNoResult(void action(), { ValueListenable<bool>? restriction, void ifRestrictedExecuteInstead()?, ErrorFilter? errorFilter, bool notifyOnlyWhenValueChanges = false, String? debugName, })

////////////////////// Factory functions from here on //////////////////////

Creates a Command for a synchronous handler function with no parameter and no return type action : handler function restriction : ValueListenable<bool> that can be used to enable/disable the command based on some other state change. true means that the Command cannot be executed. If omitted the command can be executed always except it's already executing ifRestrictedExecuteInstead if restriction is set for the command and its value is true this function will be called instead of the wrapped function. This is useful if you want to execute a different function when the command is restricted. For example you could show a dialog to let the user logg in if the restriction is because the user is not logged in. If you don't set this function, the command will just do nothing when it's restricted. As synchronous function doesn't give any the UI any chance to react on on a change of .isExecuting,isExecuting isn't supported for synchronous commands ans will throw an assert if you try to use it. Can't be used with an ValueListenableBuilder because it doesn't have a value, but you can register a handler to wait for the completion of the wrapped function. errorFilter : overrides the default set by errorFilterDefault. If false, Exceptions thrown by the wrapped function won't be caught but rethrown unless there is a listener on errors or results. notifyOnlyWhenValueChanges : the default is that the command notifies it's listeners even if the value hasn't changed. If you set this to true the command will only notify it's listeners if the value has changed. debugName optional identifier that is included when you register a globalExceptionHandler or a loggingHandler

Implementation

///
  /// Creates  a Command for a synchronous handler function with no parameter and no return type
  /// [action] : handler function
  /// [restriction] : `ValueListenable<bool>` that can be used to enable/disable
  /// the command based on some other state change. `true` means that the Command cannot be executed.
  /// If omitted the command can be executed always except it's already executing
  /// [ifRestrictedExecuteInstead] if  [restriction] is set for the command and its value is `true`
  /// this function will be called instead of the wrapped function.
  /// This is useful if you want to execute a different function when the command
  /// is restricted. For example you could show a dialog to let the user logg in
  /// if the restriction is because the user is not logged in.
  /// If you don't set this function, the command will just do nothing when it's
  /// restricted.
  /// As synchronous function doesn't give any the UI any chance to react on on a change of
  /// `.isExecuting`,isExecuting isn't supported for synchronous commands ans will throw an
  /// assert if you try to use it.
  /// Can't be used with an `ValueListenableBuilder` because it doesn't have a value, but you can
  /// register a handler to wait for the completion of the wrapped function.
  /// [errorFilter] : overrides the default set by [errorFilterDefault].
  /// If `false`, Exceptions thrown by the wrapped function won't be caught but rethrown
  /// unless there is a listener on [errors] or [results].
  /// [notifyOnlyWhenValueChanges] : the default is that the command notifies it's listeners even
  /// if the value hasn't changed. If you set this to `true` the command will only notify
  /// it's listeners if the value has changed.
  /// [debugName] optional identifier that is included when you register a [globalExceptionHandler]
  /// or a [loggingHandler]
  static Command<void, void> createSyncNoParamNoResult(
    void Function() action, {
    ValueListenable<bool>? restriction,
    void Function()? ifRestrictedExecuteInstead,
    ErrorFilter? errorFilter,
    bool notifyOnlyWhenValueChanges = false,
    String? debugName,
  }) {
    return CommandSync<void, void>(
      funcNoParam: action,
      initialValue: null,
      restriction: restriction,
      ifRestrictedExecuteInstead: ifRestrictedExecuteInstead != null
          ? (_) => ifRestrictedExecuteInstead()
          : null,
      includeLastResultInCommandResults: false,
      noReturnValue: true,
      errorFilter: errorFilter,
      notifyOnlyWhenValueChanges: notifyOnlyWhenValueChanges,
      debugName: debugName,
      noParamValue: true,
    );
  }