iOS: add support for native message dialogs

This patch will add support for native message dialogs on iOS.

Change-Id: Iba2237b371ccbdfe4c772d25c3ea925eb64e5a0c
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@theqtcompany.com>

4 files changed, 209 insertions, 2 deletions

diff --git a/src/plugins/platforms/ios/ios.pro b/src/plugins/platforms/ios/ios.pro
index bf7849b740..236234628d 100644
--- a/src/plugins/platforms/ios/ios.pro
+++ b/src/plugins/platforms/ios/ios.pro
@@ -30,7 +30,8 @@ OBJECTIVE_SOURCES = \
     qiostextresponder.mm \
     qiosmenu.mm \
     qiosfileengineassetslibrary.mm \
-    qiosfiledialog.mm
+    qiosfiledialog.mm \
+    qiosmessagedialog.mm
 
 HEADERS = \
     qiosintegration.h \
@@ -54,7 +55,8 @@ HEADERS = \
     qiosmenu.h \
     qiosfileenginefactory.h \
     qiosfileengineassetslibrary.h \
-    qiosfiledialog.h
+    qiosfiledialog.h \
+    qiosmessagedialog.h
 
 OTHER_FILES = \
     quiview_textinput.mm \
diff --git a/src/plugins/platforms/ios/qiosmessagedialog.h b/src/plugins/platforms/ios/qiosmessagedialog.h
new file mode 100644
index 0000000000..a9bd42324e
--- /dev/null
+++ b/src/plugins/platforms/ios/qiosmessagedialog.h
@@ -0,0 +1,65 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** 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 The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QIOSMESSAGEDIALOG_H
+#define QIOSMESSAGEDIALOG_H
+
+#include <QtCore/qeventloop.h>
+#include <qpa/qplatformdialoghelper.h>
+
+QT_BEGIN_NAMESPACE
+
+Q_FORWARD_DECLARE_OBJC_CLASS(UIAlertController);
+Q_FORWARD_DECLARE_OBJC_CLASS(UIAlertAction);
+
+class QIOSMessageDialog : public QPlatformMessageDialogHelper
+{
+public:
+    QIOSMessageDialog();
+    ~QIOSMessageDialog();
+
+    void exec() Q_DECL_OVERRIDE;
+    bool show(Qt::WindowFlags windowFlags, Qt::WindowModality windowModality, QWindow *parent) Q_DECL_OVERRIDE;
+    void hide() Q_DECL_OVERRIDE;
+
+private:
+    QEventLoop m_eventLoop;
+    UIAlertController *m_alertController;
+    QString messageTextPlain();
+    UIAlertAction *createAction(StandardButton button);
+};
+
+QT_END_NAMESPACE
+
+#endif // QIOSMESSAGEDIALOG_H
+
diff --git a/src/plugins/platforms/ios/qiosmessagedialog.mm b/src/plugins/platforms/ios/qiosmessagedialog.mm
new file mode 100644
index 0000000000..39f7d4b1cd
--- /dev/null
+++ b/src/plugins/platforms/ios/qiosmessagedialog.mm
@@ -0,0 +1,135 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** 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 The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#import <UIKit/UIKit.h>
+
+#include <QtGui/qwindow.h>
+#include <QtGui/private/qguiapplication_p.h>
+#include <qpa/qplatformtheme.h>
+
+#include "qiosglobal.h"
+#include "quiview.h"
+#include "qiosmessagedialog.h"
+
+QIOSMessageDialog::QIOSMessageDialog()
+    : m_alertController(Q_NULLPTR)
+{
+}
+
+QIOSMessageDialog::~QIOSMessageDialog()
+{
+    hide();
+}
+
+inline QString QIOSMessageDialog::messageTextPlain()
+{
+    // Concatenate text fragments, and remove HTML tags
+    const QSharedPointer<QMessageDialogOptions> &opt = options();
+    const QString &lineShift = QStringLiteral("\n\n");
+    const QString &informativeText = opt->informativeText();
+    const QString &detailedText = opt->detailedText();
+
+    QString text = opt->text();
+    if (!informativeText.isEmpty())
+        text += lineShift + informativeText;
+    if (!detailedText.isEmpty())
+        text += lineShift + detailedText;
+
+    text.replace(QLatin1String("<p>"), QStringLiteral("\n"), Qt::CaseInsensitive);
+    text.remove(QRegularExpression(QStringLiteral("<[^>]*>")));
+
+    return text;
+}
+
+inline UIAlertAction *QIOSMessageDialog::createAction(StandardButton button)
+{
+    const StandardButton labelButton = button == NoButton ? Ok : button;
+    const QString &standardLabel = QGuiApplicationPrivate::platformTheme()->standardButtonText(labelButton);
+    const QString &label = QPlatformTheme::removeMnemonics(standardLabel);
+
+    UIAlertActionStyle style = UIAlertActionStyleDefault;
+    if (button == Cancel)
+        style = UIAlertActionStyleCancel;
+    else if (button == Discard)
+        style = UIAlertActionStyleDestructive;
+
+    return [UIAlertAction actionWithTitle:label.toNSString() style:style handler:^(UIAlertAction *) {
+        hide();
+        if (button == NoButton)
+            emit reject();
+        else
+            emit clicked(button, buttonRole(button));
+    }];
+}
+
+void QIOSMessageDialog::exec()
+{
+    m_eventLoop.exec(QEventLoop::DialogExec);
+}
+
+bool QIOSMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality windowModality, QWindow *parent)
+{
+    Q_UNUSED(windowFlags);
+    if (m_alertController // Ensure that the dialog is not showing already
+            || !options() // Some message dialogs don't have options (QErrorMessage)
+            || windowModality != Qt::ApplicationModal // We can only do app modal dialogs
+            || QSysInfo::MacintoshVersion < QSysInfo::MV_IOS_8_0) // API limitation
+        return false;
+
+    m_alertController = [[UIAlertController
+        alertControllerWithTitle:options()->windowTitle().toNSString()
+        message:messageTextPlain().toNSString()
+        preferredStyle:UIAlertControllerStyleAlert] retain];
+
+    if (StandardButtons buttons = options()->standardButtons()) {
+        for (int i = FirstButton; i < LastButton; i<<=1) {
+            if (i & buttons)
+                [m_alertController addAction:createAction(StandardButton(i))];
+        }
+    } else {
+        // We need at least one button to allow the user close the dialog
+        [m_alertController addAction:createAction(NoButton)];
+    }
+
+    UIWindow *window = parent ? reinterpret_cast<UIView *>(parent->winId()).window : [UIApplication sharedApplication].keyWindow;
+    [window.rootViewController presentViewController:m_alertController animated:YES completion:nil];
+    return true;
+}
+
+void QIOSMessageDialog::hide()
+{
+    m_eventLoop.exit();
+    [m_alertController dismissViewControllerAnimated:YES completion:nil];
+    [m_alertController release];
+    m_alertController = Q_NULLPTR;
+}
diff --git a/src/plugins/platforms/ios/qiostheme.mm b/src/plugins/platforms/ios/qiostheme.mm
index bc40069670..dccacb2c0e 100644
--- a/src/plugins/platforms/ios/qiostheme.mm
+++ b/src/plugins/platforms/ios/qiostheme.mm
@@ -47,6 +47,7 @@
 
 #include "qiosmenu.h"
 #include "qiosfiledialog.h"
+#include "qiosmessagedialog.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -85,6 +86,7 @@ bool QIOSTheme::usePlatformNativeDialog(QPlatformTheme::DialogType type) const
 {
     switch (type) {
     case FileDialog:
+    case MessageDialog:
         return true;
     default:
         return false;
@@ -97,6 +99,9 @@ QPlatformDialogHelper *QIOSTheme::createPlatformDialogHelper(QPlatformTheme::Dia
     case FileDialog:
         return new QIOSFileDialog();
         break;
+    case MessageDialog:
+        return new QIOSMessageDialog();
+        break;
     default:
         return 0;
     }