iOS: Refactor text input handling to standalone responder

Instead of coupling the visibility of the virtual keyboard to
the first-responder status of the currently active QUIView, we
now treat first-responder as a separate state, tied directly
to QWindow activation. This fits better with the concept of
first-responders in iOS, as a UIView can become first-responder
without dealing with text input, eg when dealing with touch
events or menu actions.

The decision point on whether or not to show the virtual
keyboard is then handled by implementing the conformsToProtocol
method and selectively returning YES for the UIKeyInput protocol.
iOS internally calls _requiresKeyboardWhenFirstResponder on the
UIResponder to determine this, but since we can't override a
private method (like WKContentView in WebKit does) we have to
rely on the fact that the implementation of the method uses the
protocol conformance to make its decision.

Once the virtual keyboard is up, we then need to react to changes
to its configuration, such as keyboard type or the type of return
key. Normally this would be a simple call to [view reloadInputViews],
but iOS will not reload the built-in keyboards unless the UIResponder
returns YES for _requiresKeyboardResetOnReload. Since we again can't
override this private method (like WebKit does), we work around it
by taking advantage of the fact that iOS will treat any change to
the first-responder as a reason to do a keyboard reset. By using
a stand-alone UIResponder for text input we can init and destroy
these responders as needed, so that every call to reloadInputViews
will trigger a reset, as the responder has not been seen before.

We keep track of changes to the input-method-query, and detect
whether or not we need to bring up a new UIResponder for text
handling.

As part of this refactoring we now tie the visibility of the
virtual keyboard to the presence of a focus object that has
input-methods enabled. This means that we automatically will
track changes to input-elements through the focus changes,
and reconfigure or hide the keyboard as appropriate. As a
result the hide() method of QInputMethod becomes a no-op on
iOS.

Change-Id: I4c4834df490bc8b0bac32aeedbd819780bd5aaba
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>

1 files changed, 74 insertions, 0 deletions

diff --git a/src/plugins/platforms/ios/qiostextresponder.h b/src/plugins/platforms/ios/qiostextresponder.h
new file mode 100644
index 0000000000..7290d9e454
--- /dev/null
+++ b/src/plugins/platforms/ios/qiostextresponder.h
@@ -0,0 +1,74 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#import <UIKit/UIKit.h>
+
+#include <QtCore/qstring.h>
+
+class QIOSInputContext;
+
+@interface QIOSTextInputResponder : UIResponder <UITextInputTraits, UIKeyInput, UITextInput>
+{
+  @public
+    QString m_markedText;
+    BOOL m_inSendEventToFocusObject;
+
+  @private
+    QIOSInputContext *m_inputContext;
+}
+
+- (id)initWithInputContext:(QIOSInputContext *)context;
+- (void)notifyInputDelegate:(Qt::InputMethodQueries)updatedProperties;
+
+// UITextInputTraits
+@property(nonatomic) UITextAutocapitalizationType autocapitalizationType;
+@property(nonatomic) UITextAutocorrectionType autocorrectionType;
+@property(nonatomic) UITextSpellCheckingType spellCheckingType;
+@property(nonatomic) BOOL enablesReturnKeyAutomatically;
+@property(nonatomic) UIKeyboardAppearance keyboardAppearance;
+@property(nonatomic) UIKeyboardType keyboardType;
+@property(nonatomic) UIReturnKeyType returnKeyType;
+@property(nonatomic, getter=isSecureTextEntry) BOOL secureTextEntry;
+
+// UITextInput
+@property(nonatomic, assign) id<UITextInputDelegate> inputDelegate;
+
+@end