我正在尝试执行以下代码，但是dispatch_after方法中的代码没有运行。在我运行的实例中，else条件将始终为true，如果我在dispatch_after之前放置一个print语句，则按预期打印。是否有人可以看到会阻止它运行？
func afterAsyncRun(ref:FIRDatabaseReference, ended:Bool, count:Int, batterName:UILabel, pitcherName:UILabel) {
var count2 = count
while(ended != true) {
if(count2 < 2) {
print("current count is < 2")
} else {
let seconds = 2.0
let delay = seconds * Double(NSEC_PER_SEC) // nanoseconds per seconds
let dispatchTime = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))
dispatch_after(dispatchTime, dispatch_get_main_queue(), {
//below is the delayed code
ref.child(String(count-2)).observeSingleEventOfType(.Value, withBlock: { (snapshot2) in
var hitterRef = snapshot2.childSnapshotForPath("/Hitter")
var pitcherRef = snapshot2.childSnapshotForPath("/Pitcher")
batterName.text = (String(hitterRef.childSnapshotForPath("/fName")) + " " + String(hitterRef.childSnapshotForPath("/lname")))
pitcherName.text = (String(pitcherRef.childSnapshotForPath("/fName")) + " " + String(pitcherRef.childSnapshotForPath("/lname")))
print("successful delay")
})
count2++
})//this is where the delay code ends
}//this is where the else loop ends
}//while loops ends
print("labels updated")
}
当我没有纳秒次数乘数运行时，仍然没有任何反应。但是，等待几秒钟并终止运行后，我收到以下错误：
2017-05-25 10:10:55.191 Test[31038:2390189] XPC connection interrupted
2017-05-25 10:10:55.167 Test[31038:2390038] Communications error: <OS_xpc_error: <error: 0x106fb1b40> { count = 1, contents =
"XPCErrorDescription" => <string: 0x106fb1ef0> { length = 22, contents = "Connection interrupted" }
}>