Ios Swift 2：调用可以抛出，但它没有用'try'标记并且错误没有处理

发布于06月10日

在我安装了Xcode7测试版并将我的快速代码转换成SWIFT 2之后，我遇到了一些我无法解决的代码问题.我知道SWIFT 2是新的，所以我搜索了一下，想既然没有关于它的任何东西，我应该写一个问题.

Here is the error:个

调用可以引发，但它没有标记为"try"，错误也不是已处理

Code:

func deleteAccountDetail(){
        let entityDescription = NSEntityDescription.entityForName("AccountDetail", inManagedObjectContext: Context!)
        let request = NSFetchRequest()
        request.entity = entityDescription

        //The Line Below is where i expect the error
        let fetchedEntities = self.Context!.executeFetchRequest(request) as! [AccountDetail]

        for entity in fetchedEntities {
        self.Context!.deleteObject(entity)
        }

        do {
            try self.Context!.save()
        } catch _ {
        }

    }

Snapshot:个在此处输入图像描述

推荐答案

您必须捕获错误，就像您已经对save()Call所做的那样，并且因为您在这里处理多个错误，所以您可以在单个do-catch挡路中顺序捕获多个呼叫，如下所示:

func deleteAccountDetail() {
    let entityDescription = NSEntityDescription.entityForName("AccountDetail", inManagedObjectContext: Context!)
    let request = NSFetchRequest()
    request.entity = entityDescription

    do {
        let fetchedEntities = try self.Context!.executeFetchRequest(request) as! [AccountDetail]

        for entity in fetchedEntities {
            self.Context!.deleteObject(entity)
        }

        try self.Context!.save()
    } catch {
        print(error)
    }
}

或者正如@bames53在下面的 comments 中指出的那样，通常更好的做法是不要捕捉抛出错误的地方.可以将该方法标记为throws，然后标记为try来调用该方法.例如:

func deleteAccountDetail() throws {
    let entityDescription = NSEntityDescription.entityForName("AccountDetail", inManagedObjectContext: Context!)
    let request = NSFetchRequest()

    request.entity = entityDescription

    let fetchedEntities = try Context.executeFetchRequest(request) as! [AccountDetail]

    for entity in fetchedEntities {
        self.Context!.deleteObject(entity)
    }

    try self.Context!.save()
}