Simplify date-time formatting in textForRole()

QAbstractItemDelegatePrivate::textForRole() was formatting date and
time separately, then gluing the parts back together with space.
QLocale can do that just fine itself (it has a toString() overload
that handles a QDateTime) and might even (some day) do it better.  To
my mild surprise, this proved sufficient to fix a problem with
date-time display in tool-tips, when the date-time includes a zone.

Extracted the date-time part of an existing selftest into a test of
its own and extended it to test times of each spec-type; verified that
the non-local spec cases of this all failed before this fix.

Task-number: QTBUG-61069
Change-Id: I6d6be0c27be9a557d8afc3ced200a10b2aaff816
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

1 files changed, 3 insertions, 6 deletions

diff --git a/src/widgets/itemviews/qabstractitemdelegate.cpp b/src/widgets/itemviews/qabstractitemdelegate.cpp
index d532221092..6cb7c8600d 100644
--- a/src/widgets/itemviews/qabstractitemdelegate.cpp
+++ b/src/widgets/itemviews/qabstractitemdelegate.cpp
@@ -585,12 +585,9 @@ QString QAbstractItemDelegatePrivate::textForRole(Qt::ItemDataRole role, const Q
     case QVariant::Time:
         text = locale.toString(value.toTime(), formatType);
         break;
-    case QVariant::DateTime: {
-        const QDateTime dateTime = value.toDateTime();
-        text = locale.toString(dateTime.date(), formatType)
-             + QLatin1Char(' ')
-             + locale.toString(dateTime.time(), formatType);
-        break; }
+    case QVariant::DateTime:
+        text = locale.toString(value.toDateTime(), formatType);
+        break;
     default:
         text = value.toString();
         if (role == Qt::DisplayRole)