Add QQuickDialog::title

Dialog is incomplete without built-in support for title. All dialogs in
the examples, screenshots, webinars, and blog posts have had a custom
title. The Material and Universal designs both have specs for dialog
titles. This commit adds support for dialog titles with appropriate
looks (padding & font) out of the box.

Task-number: QTBUG-56711
Change-Id: I248150313f1ce629a7105fdbe1c70c8fcd69e1cc
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

3 files changed, 43 insertions, 1 deletions

diff --git a/src/quicktemplates2/qquickdialog.cpp b/src/quicktemplates2/qquickdialog.cpp
index 356e6c27..05e0f26d 100644
--- a/src/quicktemplates2/qquickdialog.cpp
+++ b/src/quicktemplates2/qquickdialog.cpp
@@ -56,7 +56,10 @@ QT_BEGIN_NAMESPACE
 
     \image qtquickcontrols2-page-wireframe.png
 
-    \section1 Dialog Buttons
+    \section1 Dialog Title and Buttons
+
+    Dialog's \l title is displayed by a style-specific title bar that is assigned
+    as a dialog \l header by default.
 
     Dialog's standard buttons are managed by a \l DialogButtonBox that is assigned
     as a dialog \l footer by default. The dialog's \l standardButtons property is
@@ -119,6 +122,39 @@ QQuickDialog::QQuickDialog(QObject *parent) :
 }
 
 /*!
+    \qmlproperty string QtQuick.Controls::Dialog::title
+
+    This property holds the dialog title.
+
+    The title is displayed in the dialog header.
+
+    \code
+    Dialog {
+        title: qsTr("About")
+
+        Label {
+            text: "Lorem ipsum..."
+        }
+    }
+    \endcode
+*/
+QString QQuickDialog::title() const
+{
+    Q_D(const QQuickDialog);
+    return d->title;
+}
+
+void QQuickDialog::setTitle(const QString &title)
+{
+    Q_D(QQuickDialog);
+    if (d->title == title)
+        return;
+
+    d->title = title;
+    emit titleChanged();
+}
+
+/*!
     \qmlproperty Item QtQuick.Controls::Dialog::header
 
     This property holds the dialog header item. The header item is positioned to
diff --git a/src/quicktemplates2/qquickdialog_p.h b/src/quicktemplates2/qquickdialog_p.h
index 1cd50f4a..ff8a1e79 100644
--- a/src/quicktemplates2/qquickdialog_p.h
+++ b/src/quicktemplates2/qquickdialog_p.h
@@ -58,6 +58,7 @@ class QQuickDialogPrivate;
 class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickDialog : public QQuickPopup
 {
     Q_OBJECT
+    Q_PROPERTY(QString title READ title WRITE setTitle NOTIFY titleChanged FINAL)
     Q_PROPERTY(QQuickItem *header READ header WRITE setHeader NOTIFY headerChanged FINAL)
     Q_PROPERTY(QQuickItem *footer READ footer WRITE setFooter NOTIFY footerChanged FINAL)
     Q_PROPERTY(QPlatformDialogHelper::StandardButtons standardButtons READ standardButtons WRITE setStandardButtons NOTIFY standardButtonsChanged FINAL)
@@ -66,6 +67,9 @@ class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickDialog : public QQuickPopup
 public:
     explicit QQuickDialog(QObject *parent = nullptr);
 
+    QString title() const;
+    void setTitle(const QString &title);
+
     QQuickItem *header() const;
     void setHeader(QQuickItem *header);
 
@@ -83,6 +87,7 @@ Q_SIGNALS:
     void accepted();
     void rejected();
 
+    void titleChanged();
     void headerChanged();
     void footerChanged();
     void standardButtonsChanged();
diff --git a/src/quicktemplates2/qquickdialog_p_p.h b/src/quicktemplates2/qquickdialog_p_p.h
index e5ac7066..5ea84cc8 100644
--- a/src/quicktemplates2/qquickdialog_p_p.h
+++ b/src/quicktemplates2/qquickdialog_p_p.h
@@ -67,6 +67,7 @@ public:
         return dialog->d_func();
     }
 
+    QString title;
     QQuickDialogButtonBox *buttonBox;
     QScopedPointer<QQuickPageLayout> layout;
     QPlatformDialogHelper::StandardButtons standardButtons;