.onAppear是否导致文本在SwiftUI中消失？

Question

我正在做一个简单的倒计时。我期望发生的事情是BatchId <- read.table(header = TRUE, sep = "|", text = " BatchId | dateTime | nextDate ABC053272A | 2020-04-01 00:00:48 UTC | 2020-04-02 00:29:47 UTC ABC053314A | 2020-04-02 00:29:47 UTC | 2020-04-03 00:12:58 UTC ABC053330A | 2020-04-03 00:12:58 UTC | 2020-04-04 01:16:54 UTC ABC053355A | 2020-04-04 01:16:54 UTC | 2020-04-07 00:33:57 UTC ABC053405A | 2020-04-07 00:33:57 UTC | 2020-04-08 00:46:47 UTC ABC053421A | 2020-04-08 00:46:47 UTC | 2020-04-09 00:36:56 UTC ABC053447A | 2020-04-09 00:36:56 UTC | 2020-04-10 01:26:55 UTC ABC053462A | 2020-04-10 01:26:55 UTC | 2020-04-13 08:13:50 UTC ABC053470 | 2020-04-13 08:13:50 UTC | 2020-04-14 10:07:56 UTC ABC053496A | 2020-04-14 10:07:56 UTC | 2020-04-15 11:08:59 UTC ABC053520A | 2020-04-15 11:08:59 UTC | 2020-04-16 17:51:28 UTC ABC053553A | 2020-04-16 17:51:28 UTC | 2020-04-20 04:24:53 UTC ABC053611A | 2020-04-20 04:24:53 UTC | 2020-04-22 00:09:56 UTC ABC053652A | 2020-04-22 00:09:56 UTC | 2020-04-22 12:05:49 UTC ABC053652B | 2020-04-22 12:05:49 UTC | 2020-04-23 14:12:53 UTC ABC053686 | 2020-04-23 14:12:53 UTC | 2020-04-24 12:14:55 UTC ABC053694A | 2020-04-24 12:14:55 UTC | 2020-04-28 00:08:59 UTC ABC053710A | 2020-04-28 00:08:59 UTC | 2020-04-29 00:34:56 UTC ABC053769A | 2020-04-29 00:34:56 UTC | 2020-04-30 00:59:58 UTC ABC053793A | 2020-04-30 00:59:58 UTC | 2020-05-01 00:41:54 UTC ABC053827A | 2020-05-01 00:41:54 UTC | 2020-05-05 00:53:55 UTC ABC053876A | 2020-05-05 00:53:55 UTC | 2020-05-06 04:10:55 UTC ABC053892A | 2020-05-06 04:10:55 UTC | 2020-05-07 06:22:56 UTC ABC053918A | 2020-05-07 06:22:56 UTC | 2020-05-08 06:02:55 UTC ABC053942A | 2020-05-08 06:02:55 UTC | 2020-05-11 06:43:42 UTC ABC053967A | 2020-05-11 06:43:42 UTC | 2020-05-12 07:01:57 UTC ABC053991A | 2020-05-12 07:01:57 UTC | 2020-05-13 05:08:47 UTC ABC054007A | 2020-05-13 05:08:47 UTC | 2020-05-14 03:36:55 UTC ABC054023A | 2020-05-14 03:36:55 UTC | 2020-05-15 02:32:58 UTC ABC054064A | 2020-05-15 02:32:58 UTC | 2020-05-18 04:32:57 UTC") BatchId[c("dateTime", "nextDate")] <- lapply(BatchId[c("dateTime", "nextDate")], as.POSIXct, tz = "UTC") 计数为First，然后0计数为Second。当该语句切换到else块时，HStack文本在画布中消失。为什么会发生这种情况？

0

Answer 1

这意味着当两者 HStack和first都大于0时，您的second将会显示：

if (first > 0) && (second > 0) {
    HStack {
        ...
    }
}

如果您要在其中任一> 0时显示HStack，则可以执行以下操作：

if first > 0 || second > 0 { ... }

请参阅Apple文档：

• BasicOperators