iOS: ensure keyboard is visible, even when IM hints hasn't changed

When showing a QWindow, we transfer first responder status to its
QUIView. If another QWindow was active with a text responder at
that point, the text responder will loose first responder status
in favor of the new view, and the keyboard will hide.

Now, if the new window has a focus object with the same IM state
as the previous focus object (in the previous window), m_imeState
will not change, and QIOSIntegration::update() will assume that
nothing needs to be done to show the keyboard, even if it's
actually hidden.

This patch will change the logic, so that we:
- show the keyboard if its supposed to be visible, even if
    m_imeState did not change.
- Only recreate the text responder if it needs a different
    configuration than the one we already got (not only
    from changes to Qt::ImEnabled)

Task-number: QTBUG-40695
Change-Id: I6f6788af4cbff5c7abe4f5a29e23a7cefea6b711
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@theqtcompany.com>

1 files changed, 16 insertions, 17 deletions

diff --git a/src/plugins/platforms/ios/qiosinputcontext.mm b/src/plugins/platforms/ios/qiosinputcontext.mm
index 22847b0612..a558ebe1f7 100644
--- a/src/plugins/platforms/ios/qiosinputcontext.mm
+++ b/src/plugins/platforms/ios/qiosinputcontext.mm
@@ -587,28 +587,27 @@ void QIOSInputContext::update(Qt::InputMethodQueries updatedProperties)
     qImDebug() << "fw =" << qApp->focusWindow() << "fo =" << qApp->focusObject();
 
     Qt::InputMethodQueries changedProperties = m_imeState.update(updatedProperties);
-    if (changedProperties & (Qt::ImEnabled | Qt::ImHints | Qt::ImPlatformData)) {
-        // Changes to enablement or hints require virtual keyboard reconfigure
-
-        qImDebug() << "changed IM properties" << changedProperties << "require keyboard reconfigure";
+    if (m_textResponder && changedProperties & (Qt::ImHints | Qt::ImPlatformData)) {
+        qImDebug() << "current IM state requires new text responder";
+        [m_textResponder autorelease];
+        m_textResponder = 0;
+    }
 
-        if (inputMethodAccepted()) {
-            qImDebug() << "replacing text responder with new text responder";
-            [m_textResponder autorelease];
+    if (inputMethodAccepted()) {
+        if (!m_textResponder) {
+            qImDebug() << "creating new text responder";
             m_textResponder = [[QIOSTextInputResponder alloc] initWithInputContext:this];
-            [m_textResponder becomeFirstResponder];
-        } else if ([UIResponder currentFirstResponder] == m_textResponder) {
-            qImDebug() << "IM not enabled, resigning text responder as first responder";
-            [m_textResponder resignFirstResponder];
-        } else {
-            qImDebug() << "IM not enabled. Text responder not first responder. Nothing to do";
         }
-    } else {
+        if (![m_textResponder isFirstResponder])
+            [m_textResponder becomeFirstResponder];
+
         [m_textResponder notifyInputDelegate:changedProperties];
-    }
 
-    if (changedProperties & Qt::ImCursorRectangle)
-        scrollToCursor();
+        if (changedProperties & Qt::ImCursorRectangle)
+            scrollToCursor();
+    } else if ([m_textResponder isFirstResponder]) {
+        [m_textResponder resignFirstResponder];
+    }
 }
 
 bool QIOSInputContext::inputMethodAccepted() const