Terminal: Use IOptionPage::setWidgetCreator() for settings

Less boilerplate for the implementation add user code access to
IOptionPage::{apply,finish} is planned to be removed.

Change-Id: Id8ec4006d1060be2032caf8eda6bf80760f6db22
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/plugins/terminal/terminalplugin.cpp

@@ -44,7 +44,7 @@ bool TerminalPlugin::delayedInitialize()
 
 void TerminalPlugin::extensionsInitialized()
 {
-    TerminalSettingsPage::instance().init();
+    (void) TerminalSettingsPage::instance();
     TerminalSettings::instance().readSettings(Core::ICore::settings());
 
     m_terminalPane = new TerminalPane();

src/plugins/terminal/terminalsettingspage.cpp

@@ -28,18 +28,6 @@ using namespace Utils;
 
 namespace Terminal {
 
-TerminalSettingsPage::TerminalSettingsPage()
-{
-    setId("Terminal.General");
-    setDisplayName("Terminal");
-    setCategory("ZY.Terminal");
-    setDisplayCategory("Terminal");
-    setSettings(&TerminalSettings::instance());
-    setCategoryIconPath(":/terminal/images/settingscategory_terminal.png");
-}
-
-void TerminalSettingsPage::init() {}
-
 static expected_str<void> loadXdefaults(const FilePath &path)
 {
     const expected_str<QByteArray> readResult = path.fileContents();
@@ -320,13 +308,14 @@ static expected_str<void> loadColorScheme(const FilePath &path)
     return make_unexpected(Tr::tr("Unknown color scheme format"));
 }
 
-QWidget *TerminalSettingsPage::widget()
+class TerminalSettingsPageWidget : public Core::IOptionsPageWidget
 {
-    QWidget *widget = new QWidget;
-
+public:
+    TerminalSettingsPageWidget()
+    {
         using namespace Layouting;
 
-    QFontComboBox *fontComboBox = new QFontComboBox(widget);
+        QFontComboBox *fontComboBox = new QFontComboBox(this);
         fontComboBox->setFontFilters(QFontComboBox::MonospacedFonts);
         fontComboBox->setCurrentFont(TerminalSettings::instance().font.value());
 
@@ -339,9 +328,9 @@ QWidget *TerminalSettingsPage::widget()
         QPushButton *loadThemeButton = new QPushButton(Tr::tr("Load Theme..."));
         QPushButton *resetTheme = new QPushButton(Tr::tr("Reset Theme to default"));
 
-    connect(loadThemeButton, &QPushButton::clicked, this, [widget] {
+        connect(loadThemeButton, &QPushButton::clicked, this, [this] {
             const FilePath path = FileUtils::getOpenFilePath(
-            widget,
+                this,
                 "Open Theme",
                 {},
                 "All Scheme formats (*.itermcolors *.json *.colorscheme *.theme *.theme.txt);;"
@@ -361,7 +350,7 @@ QWidget *TerminalSettingsPage::widget()
 
             const expected_str<void> result = loadColorScheme(path);
             if (!result)
-            QMessageBox::warning(widget, Tr::tr("Error"), result.error());
+                QMessageBox::warning(this, Tr::tr("Error"), result.error());
         });
 
         connect(resetTheme, &QPushButton::clicked, this, [] {
@@ -428,23 +417,37 @@ QWidget *TerminalSettingsPage::widget()
                 settings.shellArguments,
             },
             st,
-    }.attachTo(widget);
+        }.attachTo(this);
         // clang-format on
 
-    DropSupport *dropSupport = new DropSupport(widget);
+        DropSupport *dropSupport = new DropSupport(this);
         connect(dropSupport,
             &DropSupport::filesDropped,
             this,
-            [widget](const QList<DropSupport::FileSpec> &files) {
+            [this](const QList<DropSupport::FileSpec> &files) {
                 if (files.size() != 1)
                     return;
 
                 const expected_str<void> result = loadColorScheme(files.at(0).filePath);
                 if (!result)
-                    QMessageBox::warning(widget, Tr::tr("Error"), result.error());
+                    QMessageBox::warning(this, Tr::tr("Error"), result.error());
             });
+    }
 
-    return widget;
+    void apply() final {}
+};
+
+// TerminalSettingsPage
+
+TerminalSettingsPage::TerminalSettingsPage()
+{
+    setId("Terminal.General");
+    setDisplayName("Terminal");
+    setCategory("ZY.Terminal");
+    setDisplayCategory("Terminal");
+    setSettings(&TerminalSettings::instance());
+    setCategoryIconPath(":/terminal/images/settingscategory_terminal.png");
+    setWidgetCreator([] { return new TerminalSettingsPageWidget; });
 }
 
 TerminalSettingsPage &TerminalSettingsPage::instance()

src/plugins/terminal/terminalsettingspage.h

@@ -13,10 +13,6 @@ public:
     TerminalSettingsPage();
 
     static TerminalSettingsPage &instance();
-
-    void init();
-
-    QWidget *widget() override;
 };
 
 } // namespace Terminal