Shrink calendar list to remove empty space when too large

Changelog

 KAlarm Change Log
 
-=== Version 3.4.0 (KDE Applications 22.04) --- 20 January 2022 ===
-+ Allow calendars and date picker to be shown together in side panel [KDE Bug 440250]
+=== Version 3.4.0 (KDE Applications 22.04) --- 21 January 2022 ===
+* Allow calendars and date picker to be shown together in side panel [KDE Bug 440250]
+* Shrink calendar list to remove empty space when too large.
 
 === Version 3.3.5 (KDE Applications 21.12.2) --- 11 January 2022 ===
 * Fix crash after Defer is selected in alarm notification message [KDE Bug 448212]

src/mainwindow.cpp

@@ -163,6 +163,7 @@ MainWindow::MainWindow(bool restored)
 
     DataModel::widgetNeedsDatabase(this);
     mResourceSelector = new ResourceSelector(this, panelContents);
+    connect(mResourceSelector, &ResourceSelector::calendarCountChanged, this, [this]() { mResourceSelector->adjustSize(); });
     mPanelLayout->addWidget(mResourceSelector);
     mPanelLayout->addStretch();
 

src/resources/resourcemodel.cpp

 /*
  *  resourcemodel.cpp  -  models containing flat list of resources
  *  Program:  kalarm
- *  SPDX-FileCopyrightText: 2007-2021 David Jarvie <djarvie@kde.org>
+ *  SPDX-FileCopyrightText: 2007-2022 David Jarvie <djarvie@kde.org>
  *
  *  SPDX-License-Identifier: GPL-2.0-or-later
  */
@@ -614,6 +614,8 @@ ResourceView::ResourceView(ResourceFilterCheckListModel* model, QWidget* parent)
 {
     setModel(model);
     model->sort(0, Qt::AscendingOrder);
+    connect(model, &QAbstractItemModel::rowsInserted, this, &ResourceView::rowCountChanged);
+    connect(model, &QAbstractItemModel::rowsRemoved, this, &ResourceView::rowCountChanged);
 }
 
 ResourceFilterCheckListModel* ResourceView::resourceModel() const
@@ -634,6 +636,20 @@ Resource ResourceView::resource(const QModelIndex& index) const
     return static_cast<ResourceFilterCheckListModel*>(model())->resource(index);
 }
 
+/******************************************************************************
+* Return the size hint reduced to show a maximum of one empty line.
+*/
+QSize ResourceView::sizeHint() const
+{
+    const QRect lastItem = visualRect(model()->index(model()->rowCount() - 1, 0));
+    const int border = height() - viewport()->height();
+    QSize sz = QListView::sizeHint();
+    const int itemsHeight = lastItem.bottom() + lastItem.height()*0.7 + border;
+    if (itemsHeight < sz.height())
+        sz.setHeight(itemsHeight);
+    return sz;
+}
+
 /******************************************************************************
 * Called when a mouse button is released.
 * Any currently selected resource is deselected.

src/resources/resourcemodel.h

 /*
  *  resourcemodel.h  -  models containing flat list of resources
  *  Program:  kalarm
- *  SPDX-FileCopyrightText: 2010-2021 David Jarvie <djarvie@kde.org>
+ *  SPDX-FileCopyrightText: 2010-2022 David Jarvie <djarvie@kde.org>
  *
  *  SPDX-License-Identifier: GPL-2.0-or-later
  */
@@ -229,6 +229,10 @@ public:
     ResourceFilterCheckListModel* resourceModel() const;
     Resource  resource(int row) const;
     Resource  resource(const QModelIndex&) const;
+    QSize     sizeHint() const override;
+
+Q_SIGNALS:
+    void rowCountChanged();
 
 protected:
     void mouseReleaseEvent(QMouseEvent*) override;

src/resourceselector.cpp

 /*
  *  resourceselector.cpp  -  calendar resource selection widget
  *  Program:  kalarm
- *  SPDX-FileCopyrightText: 2006-2021 David Jarvie <djarvie@kde.org>
+ *  SPDX-FileCopyrightText: 2006-2022 David Jarvie <djarvie@kde.org>
  *  Based on KOrganizer's ResourceView class and KAddressBook's ResourceSelection class,
  *  SPDX-FileCopyrightText: 2003, 2004 Cornelius Schumacher <schumacher@kde.org>
  *  SPDX-FileCopyrightText: 2003-2004 Reinhold Kainhofer <reinhold@kainhofer.com>
@@ -64,6 +64,11 @@ ResourceSelector::ResourceSelector(MainWindow* parentWindow, QWidget* parent)
     connect(mListView->selectionModel(), &QItemSelectionModel::selectionChanged, this, &ResourceSelector::selectionChanged);
     mListView->setContextMenuPolicy(Qt::CustomContextMenu);
     connect(mListView, &ResourceView::customContextMenuRequested, this, &ResourceSelector::contextMenuRequested);
+    connect(mListView, &ResourceView::rowCountChanged, this, [this]()
+            {
+                mListViewAdjustment = mListView->sizeHint().height() - mListView->height();
+                Q_EMIT calendarCountChanged();
+            });
     mListView->setWhatsThis(i18nc("@info:whatsthis",
                                   "List of available calendars of the selected type. The checked state shows whether a calendar "
                                  "is enabled (checked) or disabled (unchecked). The default calendar is shown in bold."));
@@ -551,6 +556,17 @@ CalEvent::Type ResourceSelector::currentResourceType() const
     }
 }
 
+/******************************************************************************
+* Resize this widget to fit its list view size hint.
+* This will adjust the size according to the change in list view height when
+* the signal calendarCountChanged() was last emitted.
+*/
+void ResourceSelector::adjustSize()
+{
+    mListView->resize(mListView->width(), mListView->height() + mListViewAdjustment);
+    resize(width(), height() + mListViewAdjustment);
+}
+
 void ResourceSelector::resizeEvent(QResizeEvent* re)
 {
     Q_EMIT resized(re->oldSize(), re->size());

src/resourceselector.h

 /*
  *  resourceselector.h  -  alarm calendar resource selection widget
  *  Program:  kalarm
- *  SPDX-FileCopyrightText: 2006-2021 David Jarvie <djarvie@kde.org>
+ *  SPDX-FileCopyrightText: 2006-2022 David Jarvie <djarvie@kde.org>
  *  Based on KOrganizer's ResourceView class and KAddressBook's ResourceSelection class,
  *  SPDX-FileCopyrightText: 2003, 2004 Cornelius Schumacher <schumacher@kde.org>
  *  SPDX-FileCopyrightText: 2003-2004 Reinhold Kainhofer <reinhold@kainhofer.com>
@@ -40,9 +40,19 @@ public:
     explicit ResourceSelector(MainWindow* parentWindow, QWidget* parent = nullptr);
     void  initActions(KActionCollection*);
 
+    /** Resize this widget to fit its list view size hint.
+     *  This will adjust the size according to the change in list view height
+     *  when the signal calendarCountChanged() was last emitted.
+     */
+    void  adjustSize();
+
 Q_SIGNALS:
+    /** Emitted when the widget has been resized. */
     void  resized(const QSize& oldSize, const QSize& newSize);
 
+    /** Emitted when the number of calendars has changed. */
+    void  calendarCountChanged();
+
 protected:
     void  resizeEvent(QResizeEvent*) override;
 
@@ -88,6 +98,7 @@ private:
     QAction*        mActionImport {nullptr};
     QAction*        mActionExport {nullptr};
     KToggleAction*  mActionSetDefault {nullptr};
+    int             mListViewAdjustment {0};   // adjustment in mListView height when calendarCountChanged() was last emitted
 };
 
 // vim: et sw=4: