iOS: Keep undo/redo widgets enabled on the undo shortcut bar after undo

Having two undo/redo operations on the rebuilt undo stack always enables
the undo/redo widgets on the shorcut bar. This might be more desirable than
the current behavior that only allows one undo from the shortcut bar.

Fixes: QTBUG-63393
Change-Id: I2c99f27895def47b58534035461ceb7b4e5c3057
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
(cherry picked from commit 3b155973c494e847b821f0b5675a061f4e424a6c)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 14 insertions, 1 deletions

diff --git a/src/plugins/platforms/ios/qiostextresponder.mm b/src/plugins/platforms/ios/qiostextresponder.mm
index 5d32f218fc..0cc8c0ec54 100644
--- a/src/plugins/platforms/ios/qiostextresponder.mm
+++ b/src/plugins/platforms/ios/qiostextresponder.mm
@@ -514,15 +514,23 @@
         // from within a undo callback.
         NSUndoManager *undoMgr = self.undoManager;
         [undoMgr removeAllActions];
+
+        [undoMgr beginUndoGrouping];
+        [undoMgr registerUndoWithTarget:self selector:@selector(undo) object:nil];
+        [undoMgr endUndoGrouping];
         [undoMgr beginUndoGrouping];
         [undoMgr registerUndoWithTarget:self selector:@selector(undo) object:nil];
         [undoMgr endUndoGrouping];
 
-        // Schedule an operation that we immediately pop off to be able to schedule a redo
+        // Schedule operations that we immediately pop off to be able to schedule redos
+        [undoMgr beginUndoGrouping];
+        [undoMgr registerUndoWithTarget:self selector:@selector(registerRedo) object:nil];
+        [undoMgr endUndoGrouping];
         [undoMgr beginUndoGrouping];
         [undoMgr registerUndoWithTarget:self selector:@selector(registerRedo) object:nil];
         [undoMgr endUndoGrouping];
         [undoMgr undo];
+        [undoMgr undo];
 
         // Note that, perhaps because of a bug in UIKit, the buttons on the shortcuts bar ends up
         // disabled if a undo/redo callback doesn't lead to a [UITextInputDelegate textDidChange].
@@ -530,6 +538,11 @@
         // become disabled when there is nothing more to undo (Qt didn't change anything upon receiving
         // an undo request). This seems to be OK behavior, so we let it stay like that unless it shows
         // to cause problems.
+
+        // QTBUG-63393: Having two operations on the rebuilt undo stack keeps the undo/redo widgets
+        // always enabled on the shortcut bar. This workaround was found by experimenting with
+        // removing the removeAllActions call, and is related to the unknown internal implementation
+        // details of how the shortcut bar updates the dimming of its buttons.
     });
 }