将反应性 Cocoa doNext^ 转换为 Swift

Question

我有以下 Obj-C 方法：

- (RACSignal *)updateCurrentConditions {
    return [[self.client fetchCurrent:self.coordinate] doNext:^(WXCondition *condition) {
        self.currentCondition = condition;
    }];
}

我正试图弄清楚如何将其转换为 Swift，但我不确定如何正确返回它。

我该怎么做：

[[self.client fetchCurrent:self.coordinate] doNext:^(WXCondition *condition) {}];?

func updateCurrentConditions() -> RACSignal {
    return client.fetchCurrent(coordinate: coordinate) {
        currentCondition = condition
    }
}

这里是ReactiveCocoa 的链接以及有关-doNext: 的信息

Answer 1

你可以试试这个：

func updateCurrentConditions() -> RACSignal {
  let fetchSignal = client.fetchCurrent(coordinate: coordinate)
  return fetchSignal.doNext(block: {condition: WXCondition? -> Void in
    let wxCondition = condition as WXCondition
    currentCondition = wxCondition
  })
}

Answer 2

fetchCurrent 方法返回一个 RACSignal。另外，doNext 将id 作为方法参数，所以我猜你需要强制转换：

func updateCurrentConditions() -> RACSignal {
    let fetchSignal = client.fetchCurrent(coordinate: coordinate)
    return fetchSignal.doNext(condition) {
        let wxCondition = condition as WXCondition
        currentCondition = wxCondition
    }
}