[英]Calling GraphQL appSync requests and wait for the result to come back Swift iOS
我希望我的应用程序等到请求结果返回。 所以在下面的块中,我想要做的是如果请求的查询返回空结果,我想调用“self.insertCreditRecord”。 有人做过吗? appSyncClient?.fetch(query: selectQuery, cachePolicy: .fetchIgnoringCacheData) {(result, error) in if error?= nil { print(error.?localizedDescription?? "") return }
result?.data?.listTranscriberConfigs?.items!.forEach {
if let credit = Double($0?.value ?? "0.0")
{
UserCredit.id = ""
UserCredit.id = $0?.id ?? ""
UserCredit.email = $0?.param ?? ""
UserCredit.credit = credit
}
if UserCredit.id == "" {
self.insertCreditRecord(email: email)
}
print(($0?.param)! + " " + ($0?.value)!)
}
}
您只需要在 function 中使用完成处理程序即可忽略 null 返回
例如
typealias CompletionHandler = (success:Bool) -> Void
func downloadFileFromURL(url: NSURL,completionHandler: CompletionHandler) {
// download code.
let flag = true // true if download succeed,false otherwise
completionHandler(success: flag)
}
// How to use it.
downloadFileFromURL(NSURL(string: "url_str")!, { (success) -> Void in
// When download completes,control flow goes here.
if success {
// download success
} else {
// download fail
}
})
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