QQuickDialog: simplify the button box handling

Just fill in the footer with a button box by default from the styles.
This makes the next step easier, to provide also a default title bar
in the header.

Task-number: QTBUG-56711
Change-Id: I621a61f29f9ba2fe4b7e907d81da5988133a98c8
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

7 files changed, 22 insertions, 155 deletions

diff --git a/src/imports/controls/Dialog.qml b/src/imports/controls/Dialog.qml
index ce6df0f6..3322a6ea 100644
--- a/src/imports/controls/Dialog.qml
+++ b/src/imports/controls/Dialog.qml
@@ -59,7 +59,7 @@ T.Dialog {
         border.color: Default.frameDarkColor
     }
 
-    buttonBox: DialogButtonBox {
-        position: DialogButtonBox.Footer
+    footer: DialogButtonBox {
+        visible: count > 0
     }
 }
diff --git a/src/imports/controls/material/Dialog.qml b/src/imports/controls/material/Dialog.qml
index 1e2e50ac..7e9fafbe 100644
--- a/src/imports/controls/material/Dialog.qml
+++ b/src/imports/controls/material/Dialog.qml
@@ -80,7 +80,7 @@ T.Dialog {
         }
     }
 
-    buttonBox: DialogButtonBox {
-        position: DialogButtonBox.Footer
+    footer: DialogButtonBox {
+        visible: count > 0
     }
 }
diff --git a/src/imports/controls/universal/Dialog.qml b/src/imports/controls/universal/Dialog.qml
index 0f00b760..bff289d9 100644
--- a/src/imports/controls/universal/Dialog.qml
+++ b/src/imports/controls/universal/Dialog.qml
@@ -63,7 +63,7 @@ T.Dialog {
         border.width: 1 // FlyoutBorderThemeThickness
     }
 
-    buttonBox: DialogButtonBox {
-        position: DialogButtonBox.Footer
+    footer: DialogButtonBox {
+        visible: count > 0
     }
 }
diff --git a/src/quicktemplates2/qquickdialog.cpp b/src/quicktemplates2/qquickdialog.cpp
index eaa7dbb2..356e6c27 100644
--- a/src/quicktemplates2/qquickdialog.cpp
+++ b/src/quicktemplates2/qquickdialog.cpp
@@ -38,10 +38,6 @@
 #include "qquickdialog_p_p.h"
 #include "qquickdialogbuttonbox_p.h"
 
-#include <QtQml/qqmlinfo.h>
-#include <QtQml/qqmlcontext.h>
-#include <QtQml/qqmlcomponent.h>
-
 QT_BEGIN_NAMESPACE
 
 /*!
@@ -62,20 +58,14 @@ QT_BEGIN_NAMESPACE
 
     \section1 Dialog Buttons
 
-    Dialog's standard buttons are managed by \l DialogButtonBox. When a button box
-    is assigned as a dialog \l footer or \l header, the dialog's \l standardButtons
-    property is forwarded to the respective property of the button box. Furthermore,
-    the \l {DialogButtonBox::}{accepted()} and \l {DialogButtonBox::}{rejected()}
+    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
+    forwarded to the respective property of the button box. Furthermore, the
+    \l {DialogButtonBox::}{accepted()} and \l {DialogButtonBox::}{rejected()}
     signals of the button box are connected to the respective signals in Dialog.
 
     \snippet qtquickcontrols2-dialog.qml 1
 
-    \note If any standard buttons are specified for the dialog but no button box has
-    been assigned as a footer or header, Dialog automatically creates an instance of
-    \l buttonBox, and assigns it as a footer or header of the dialog depending on the
-    value of the \l {DialogButtonBox::}{position} property. All built-in Dialog styles
-    assign the button box as a footer.
-
     \section1 Modal Dialogs
 
     A \l {Popup::}{modal} dialog blocks input to other content beneath
@@ -121,40 +111,6 @@ QT_BEGIN_NAMESPACE
     \sa accepted()
 */
 
-void QQuickDialogPrivate::createButtonBox()
-{
-    Q_Q(QQuickDialog);
-    QQmlContext *context = qmlContext(q);
-    if (!context || !buttonBoxComponent)
-        return;
-
-    QObject *object = buttonBoxComponent->create(context);
-    QQuickDialogButtonBox *buttonBox = qobject_cast<QQuickDialogButtonBox *>(object);
-    if (!buttonBox) {
-        if (object) {
-            qmlInfo(q) << "buttonBox must be an instance of DialogButtonBox";
-            delete object;
-        }
-        return;
-    }
-
-    if (buttonBox->position() == QQuickDialogButtonBox::Header) {
-        if (layout->header()) {
-            qmlInfo(q) << "Custom header detected. Cannot assign buttonBox as a header. No standard buttons will appear in the header.";
-            delete buttonBox;
-        } else {
-            q->setHeader(buttonBox);
-        }
-    } else {
-        if (layout->footer()) {
-            qmlInfo(q) << "Custom footer detected. Cannot assign buttonBox as a footer. No standard buttons will appear in the footer.";
-            delete buttonBox;
-        } else {
-            q->setFooter(buttonBox);
-        }
-    }
-}
-
 QQuickDialog::QQuickDialog(QObject *parent) :
     QQuickPopup(*(new QQuickDialogPrivate), parent)
 {
@@ -176,7 +132,7 @@ QQuickDialog::QQuickDialog(QObject *parent) :
     header automatically sets the respective \l DialogButtonBox::position,
     \l ToolBar::position, or \l TabBar::position property to \c Header.
 
-    \sa footer, buttonBox
+    \sa footer
 */
 QQuickItem *QQuickDialog::header() const
 {
@@ -223,7 +179,7 @@ void QQuickDialog::setHeader(QQuickItem *header)
     footer automatically sets the respective \l DialogButtonBox::position,
     \l ToolBar::position, or \l TabBar::position property to \c Footer.
 
-    \sa header, buttonBox
+    \sa header
 */
 QQuickItem *QQuickDialog::footer() const
 {
@@ -257,33 +213,6 @@ void QQuickDialog::setFooter(QQuickItem *footer)
 }
 
 /*!
-    \qmlproperty Component QtQuick.Controls::Dialog::buttonBox
-
-    This property holds a delegate for creating a button box.
-
-    A button box is only created if any standard buttons are set.
-    The \l {DialogButtonBox::}{position} property determines whether
-    the button box is assigned as a \l header or \l footer.
-
-    \sa standardButtons, header, footer, DialogButtonBox
-*/
-QQmlComponent *QQuickDialog::buttonBox() const
-{
-    Q_D(const QQuickDialog);
-    return d->buttonBoxComponent;
-}
-
-void QQuickDialog::setButtonBox(QQmlComponent *box)
-{
-    Q_D(QQuickDialog);
-    if (d->buttonBoxComponent == box)
-        return;
-
-    d->buttonBoxComponent = box;
-    emit buttonBoxChanged();
-}
-
-/*!
     \qmlproperty enumeration QtQuick.Controls::Dialog::standardButtons
 
     This property holds a combination of standard buttons that are used by the dialog.
@@ -311,7 +240,7 @@ void QQuickDialog::setButtonBox(QQmlComponent *box)
     \value Dialog.Ignore An "Ignore" button defined with the \c AcceptRole.
     \value Dialog.NoButton An invalid button.
 
-    \sa buttonBox, DialogButtonBox
+    \sa DialogButtonBox
 */
 QPlatformDialogHelper::StandardButtons QQuickDialog::standardButtons() const
 {
@@ -326,12 +255,8 @@ void QQuickDialog::setStandardButtons(QPlatformDialogHelper::StandardButtons but
         return;
 
     d->standardButtons = buttons;
-    if (isComponentComplete()) {
-        if (d->buttonBox)
-            d->buttonBox->setStandardButtons(buttons);
-        else if (buttons)
-            d->createButtonBox();
-    }
+    if (d->buttonBox)
+        d->buttonBox->setStandardButtons(buttons);
     emit standardButtonsChanged();
 }
 
@@ -361,14 +286,6 @@ void QQuickDialog::reject()
     emit rejected();
 }
 
-void QQuickDialog::componentComplete()
-{
-    Q_D(QQuickDialog);
-    QQuickPopup::componentComplete();
-    if (!d->buttonBox && d->standardButtons)
-        d->createButtonBox();
-}
-
 void QQuickDialog::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
 {
     Q_D(QQuickDialog);
diff --git a/src/quicktemplates2/qquickdialog_p.h b/src/quicktemplates2/qquickdialog_p.h
index 2c7eee95..1cd50f4a 100644
--- a/src/quicktemplates2/qquickdialog_p.h
+++ b/src/quicktemplates2/qquickdialog_p.h
@@ -53,7 +53,6 @@
 
 QT_BEGIN_NAMESPACE
 
-class QQmlComponent;
 class QQuickDialogPrivate;
 
 class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickDialog : public QQuickPopup
@@ -61,7 +60,6 @@ class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickDialog : public QQuickPopup
     Q_OBJECT
     Q_PROPERTY(QQuickItem *header READ header WRITE setHeader NOTIFY headerChanged FINAL)
     Q_PROPERTY(QQuickItem *footer READ footer WRITE setFooter NOTIFY footerChanged FINAL)
-    Q_PROPERTY(QQmlComponent *buttonBox READ buttonBox WRITE setButtonBox NOTIFY buttonBoxChanged FINAL)
     Q_PROPERTY(QPlatformDialogHelper::StandardButtons standardButtons READ standardButtons WRITE setStandardButtons NOTIFY standardButtonsChanged FINAL)
     Q_FLAGS(QPlatformDialogHelper::StandardButtons)
 
@@ -74,9 +72,6 @@ public:
     QQuickItem *footer() const;
     void setFooter(QQuickItem *footer);
 
-    QQmlComponent *buttonBox() const;
-    void setButtonBox(QQmlComponent *box);
-
     QPlatformDialogHelper::StandardButtons standardButtons() const;
     void setStandardButtons(QPlatformDialogHelper::StandardButtons buttons);
 
@@ -90,11 +85,9 @@ Q_SIGNALS:
 
     void headerChanged();
     void footerChanged();
-    void buttonBoxChanged();
     void standardButtonsChanged();
 
 protected:
-    void componentComplete() override;
     void geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry) override;
     void paddingChange(const QMarginsF &newPadding, const QMarginsF &oldPadding) override;
 
diff --git a/src/quicktemplates2/qquickdialog_p_p.h b/src/quicktemplates2/qquickdialog_p_p.h
index a893690d..e5ac7066 100644
--- a/src/quicktemplates2/qquickdialog_p_p.h
+++ b/src/quicktemplates2/qquickdialog_p_p.h
@@ -53,7 +53,6 @@
 
 QT_BEGIN_NAMESPACE
 
-class QQmlComponent;
 class QQuickDialogButtonBox;
 
 class QQuickDialogPrivate : public QQuickPopupPrivate
@@ -61,17 +60,14 @@ class QQuickDialogPrivate : public QQuickPopupPrivate
     Q_DECLARE_PUBLIC(QQuickDialog)
 
 public:
-    QQuickDialogPrivate() : buttonBox(nullptr), buttonBoxComponent(nullptr) { }
+    QQuickDialogPrivate() : buttonBox(nullptr) { }
 
     static QQuickDialogPrivate *get(QQuickDialog *dialog)
     {
         return dialog->d_func();
     }
 
-    void createButtonBox();
-
     QQuickDialogButtonBox *buttonBox;
-    QQmlComponent *buttonBoxComponent;
     QScopedPointer<QQuickPageLayout> layout;
     QPlatformDialogHelper::StandardButtons standardButtons;
 };
diff --git a/tests/auto/controls/data/tst_dialog.qml b/tests/auto/controls/data/tst_dialog.qml
index d4cbc222..632bb0c4 100644
--- a/tests/auto/controls/data/tst_dialog.qml
+++ b/tests/auto/controls/data/tst_dialog.qml
@@ -62,16 +62,6 @@ TestCase {
     }
 
     Component {
-        id: headerBox
-        DialogButtonBox { position: DialogButtonBox.Header }
-    }
-
-    Component {
-        id: footerBox
-        DialogButtonBox { position: DialogButtonBox.Footer }
-    }
-
-    Component {
         id: signalSpy
         SignalSpy { }
     }
@@ -80,8 +70,7 @@ TestCase {
         var control = dialog.createObject(testCase)
         verify(control)
         verify(!control.header)
-        verify(!control.footer)
-        verify(control.buttonBox)
+        verify(control.footer)
         compare(control.standardButtons, 0)
         control.destroy()
     }
@@ -122,22 +111,18 @@ TestCase {
 
     function test_buttonBox_data() {
         return [
-            { tag: "default header", property: "header", buttonBox: headerBox },
-            { tag: "default footer", property: "footer", buttonBox: footerBox },
-            { tag: "custom header", property: "header", position: DialogButtonBox.Header },
-            { tag: "custom footer", property: "footer", position: DialogButtonBox.Footer }
+            { tag: "default" },
+            { tag: "custom", custom: true }
         ]
     }
 
     function test_buttonBox(data) {
         var control = dialog.createObject(testCase)
 
-        if (data.buttonBox)
-            control.buttonBox = data.buttonBox
-        else
-            control[data.property] = buttonBox.createObject(testCase, {position: data.position})
+        if (data.custom)
+            control.footer = buttonBox.createObject(testCase)
         control.standardButtons = Dialog.Ok | Dialog.Cancel
-        var box = control[data.property]
+        var box = control.footer
         verify(box)
         compare(box.standardButtons, Dialog.Ok | Dialog.Cancel)
 
@@ -192,30 +177,6 @@ TestCase {
         control.destroy()
     }
 
-    function test_warnings() {
-        var control = dialog.createObject(testCase)
-        verify(control)
-
-        var testComponent = Qt.createComponent("TestItem.qml")
-        verify(testComponent)
-
-        control.buttonBox = headerBox
-        control.header = testComponent.createObject(testCase)
-        ignoreWarning(Qt.resolvedUrl("tst_dialog.qml") + ":56:9: QML Dialog: Custom header detected. Cannot assign buttonBox as a header. No standard buttons will appear in the header.")
-        control.standardButtons = Dialog.Apply
-
-        control.buttonBox = footerBox
-        control.footer = testComponent.createObject(testCase)
-        ignoreWarning(Qt.resolvedUrl("tst_dialog.qml") + ":56:9: QML Dialog: Custom footer detected. Cannot assign buttonBox as a footer. No standard buttons will appear in the footer.")
-        control.standardButtons = Dialog.Cancel
-
-        control.buttonBox = testComponent
-        ignoreWarning(Qt.resolvedUrl("tst_dialog.qml") + ":56:9: QML Dialog: buttonBox must be an instance of DialogButtonBox")
-        control.standardButtons = Dialog.Ok
-
-        control.destroy()
-    }
-
     function test_layout() {
         var control = dialog.createObject(testCase, {width: 100, height: 100})
         verify(control)