Changeset 277386 in webkit

Timestamp:

May 12, 2021, 1:40:15 PM (5 years ago)

Author:

Aditya Keerthi

Message:

REGRESSION (r275297): Unexpected autofocus when switching tabs
​https://bugs.webkit.org/show_bug.cgi?id=225710
<rdar://problem/77542939>

Reviewed by Wenson Hsieh.

r275297 introduced logic to handle a focus environment change by
advancing to the next or previous focusable element, depending on the
focus context's heading direction. This logic enables a tab or a
shift+tab to change the focus from browser chrome directly to an
element on a web page.

However, the focus environment can change through mechanisms other than
tab / shift+tab. One example of this is when a user switches tabs. In
these cases, the UIFocusHeading supplied by the focus context is
UIFocusHeadingNone. Nevertheless, we unconditionally call
-[WKContentView _becomeFirstResponderWithSelectionMovingForward:completionHandler:]
when the focus context changes. Consequently, an element on the web page
is always focused when the WKContentView gains focus.

• UIProcess/ios/WKContentView.mm:

(-[WKContentView didUpdateFocusInContext:withAnimationCoordinator:]):

To fix, ensure we only focus an element on the page if the focus heading
is UIFocusHeadingNext or UIFocusHeadingPrevious. UIFocusHeadingNext will
focus the first focusable element, while UIFocusHeadingPrevious will focus
the last focusable element.

Note that a call to -[WKContentView becomeFirstResponder] is not made
if the focus heading is UIFocusHeadingNone. From my testing, I observed
that the view already was the first responder in that case.

Location:

trunk/Source/WebKit

Files:

• ChangeLog (modified) (1 diff)
• UIProcess/ios/WKContentView.mm (modified) (1 diff)

trunk/Source/WebKit/ChangeLog

@@ +1 @@
+2021-05-12  Aditya Keerthi  <akeerthi@apple.com>
+
+        REGRESSION (r275297): Unexpected autofocus when switching tabs
+        https://bugs.webkit.org/show_bug.cgi?id=225710
+        <rdar://problem/77542939>
+
+        Reviewed by Wenson Hsieh.
+
+        r275297 introduced logic to handle a focus environment change by
+        advancing to the next or previous focusable element, depending on the
+        focus context's heading direction. This logic enables a tab or a
+        shift+tab to change the focus from browser chrome directly to an
+        element on a web page.
+
+        However, the focus environment can change through mechanisms other than
+        tab / shift+tab. One example of this is when a user switches tabs. In
+        these cases, the UIFocusHeading supplied by the focus context is
+        UIFocusHeadingNone. Nevertheless, we unconditionally call
+        `-[WKContentView _becomeFirstResponderWithSelectionMovingForward:completionHandler:]`
+        when the focus context changes. Consequently, an element on the web page
+        is always focused when the WKContentView gains focus.
+
+        * UIProcess/ios/WKContentView.mm:
+        (-[WKContentView didUpdateFocusInContext:withAnimationCoordinator:]):
+
+        To fix, ensure we only focus an element on the page if the focus heading
+        is UIFocusHeadingNext or UIFocusHeadingPrevious. UIFocusHeadingNext will
+        focus the first focusable element, while UIFocusHeadingPrevious will focus
+        the last focusable element.
+
+        Note that a call to `-[WKContentView becomeFirstResponder]` is not made
+        if the focus heading is UIFocusHeadingNone. From my testing, I observed
+        that the view already was the first responder in that case.
+
 2021-05-12  Chris Dumez  <cdumez@apple.com>
 

trunk/Source/WebKit/UIProcess/ios/WKContentView.mm

@@ -556 +556 @@
 - (void)didUpdateFocusInContext:(UIFocusUpdateContext *)context withAnimationCoordinator:(UIFocusAnimationCoordinator *)coordinator
 {
-    if (context.nextFocusedView == self)
-        [self _becomeFirstResponderWithSelectionMovingForward:context.focusHeading == UIFocusHeadingNext completionHandler:nil];
+    if (context.nextFocusedView == self) {
+        if (context.focusHeading & UIFocusHeadingNext)
+            [self _becomeFirstResponderWithSelectionMovingForward:YES completionHandler:nil];
+        else if (context.focusHeading & UIFocusHeadingPrevious)
+            [self _becomeFirstResponderWithSelectionMovingForward:NO completionHandler:nil];
+    }
 }