Swift 3 - 投掷函数类型的转换无效

Question

我是新手,
我不明白为什么即使做了do catch治疗也会出现这个错误.

我正在阅读类似的问题,到目前为止,他们都没有解决这个错误:
Invalid conversion from throwing function type '(_) throws -> (). to non-throwing function type '([BeaconModel]) -> ()'在线 BeaconModel.fetchBeaconsFromRestApi(completionHandler: { .....

带有错误的代码段:

do{

    let path = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
    let db = try Connection("\(path)/db.sqlite3")

    let beaconsTbl = Table("beacons")
    let id = Expression<Int64>("id")
    let uuid = Expression<String>("uuid")
    let major = Expression<String>("major")
    let minor = Expression<String>("minor")

    try db.run(beaconsTbl.create { t in
        t.column(id, primaryKey: true)
        t.column(uuid)
        t.column(major)
        t.column(minor)
    })

    BeaconModel.fetchBeaconsFromRestApi(completionHandler: {
        beacons in
        for item in beacons{

            let insert = beaconsTbl.insert(id <- item.id!, uuid <- item.uuid!, major <- item.major!, minor <- item.minor!)
            try db.run(insert)
        }
    })

} catch {
    print("Error creating the database")
}

获取方法:

static func fetchBeaconsFromRestApi( completionHandler: @escaping (_ beacons: [BeaconModel]) -> ()){

    Alamofire.request(Constants.Beacons.URLS.ListAllbeacons).responseArray(keyPath: "data") { (response: DataResponse<[BeaconModel]>) in

        let beaconsArray = response.result.value
        if let beaconsArray = beaconsArray {
            completionHandler(beaconsArray)
        }
    }
}

它使用Alamofire和AlamofireObjectMapper.你能看到我错过的东西吗？

谢谢你的帮助

Answer 1

completionHandler在fetchBeaconsFromRestApi不应该扔.所以,你应该换了所有投掷电话do - catch:

BeaconModel.fetchBeaconsFromRestApi(completionHandler: {
    beacons in
    for item in beacons{

        let insert = beaconsTbl.insert(id <- item.id!, uuid <- item.uuid!, major <- item.major!, minor <- item.minor!
        do {
            try db.run(insert)
        } catch {
            print("Error creating the database")
        }
    }
})