Add Selection Mode

The selection mode action is a checkable toggle action named
"Select Files and Folders" which has "Space" as the default
shortcut.

In selection mode a bottom bar with contextual actions is shown.
These should mostly mirror the actions which are available through
the right-click context menu aka DolphinContextMenu.

Resizing of the window might make a overflow button appear in the
bottom selection mode bar.

This commit makes press and hold in the view activate selection
mode. This behaviour is not triggered if the press and hold is
used to either start a rubberband selection or a drag operation
within a short time. The length of the short timeframe is defined
by a QStyleHint. This is currently not implemented in touch
because I can't test it.

Mix the selection mode bars' background colors using a nice
combination of colors from the current color scheme

BUG: 427202

1 files changed, 98 insertions, 8 deletions

diff --git a/src/dolphinviewcontainer.cpp b/src/dolphinviewcontainer.cpp
index 5d177c93a..dd72a6d66 100644
--- a/src/dolphinviewcontainer.cpp
+++ b/src/dolphinviewcontainer.cpp
@@ -12,11 +12,13 @@
 #include "filterbar/filterbar.h"
 #include "global.h"
 #include "search/dolphinsearchbox.h"
+#include "selectionmode/selectionmodetopbar.h"
 #include "statusbar/dolphinstatusbar.h"
 #include "views/viewmodecontroller.h"
 #include "views/viewproperties.h"
 #include "dolphin_detailsmodesettings.h"
 
+#include <KActionCollection>
 #if HAVE_KACTIVITIES
 #include <KActivities/ResourceInstance>
 #endif
@@ -32,14 +34,28 @@
 #include <KUrlComboBox>
 
 #include <QDropEvent>
+#include <QGridLayout>
 #include <QGuiApplication>
 #include <QLoggingCategory>
 #include <QMimeData>
 #include <QTimer>
 #include <QUrl>
-#include <QVBoxLayout>
 #include <QDesktopServices>
 
+#include <iostream>
+
+// An overview of the widgets contained by this ViewContainer
+struct LayoutStructure {
+    int searchBox               = 0;
+    int messageWidget           = 1;
+    int selectionModeTopBar     = 2;
+    int view                    = 3;
+    int selectionModeBottomBar  = 4;
+    int filterBar               = 5;
+    int statusBar               = 6;
+};
+constexpr LayoutStructure positionFor;
+
 DolphinViewContainer::DolphinViewContainer(const QUrl& url, QWidget* parent) :
     QWidget(parent),
     m_topLayout(nullptr),
@@ -48,8 +64,10 @@ DolphinViewContainer::DolphinViewContainer(const QUrl& url, QWidget* parent) :
     m_searchBox(nullptr),
     m_searchModeEnabled(false),
     m_messageWidget(nullptr),
+    m_selectionModeTopBar{nullptr},
     m_view(nullptr),
     m_filterBar(nullptr),
+    m_selectionModeBottomBar{nullptr},
     m_statusBar(nullptr),
     m_statusBarTimer(nullptr),
     m_statusBarTimestamp(),
@@ -60,7 +78,7 @@ DolphinViewContainer::DolphinViewContainer(const QUrl& url, QWidget* parent) :
 {
     hide();
 
-    m_topLayout = new QVBoxLayout(this);
+    m_topLayout = new QGridLayout(this);
     m_topLayout->setSpacing(0);
     m_topLayout->setContentsMargins(0, 0, 0, 0);
 
@@ -187,16 +205,16 @@ DolphinViewContainer::DolphinViewContainer(const QUrl& url, QWidget* parent) :
     connect(undoManager, &KIO::FileUndoManager::jobRecordingFinished,
             this, &DolphinViewContainer::delayedStatusBarUpdate);
 
-    m_topLayout->addWidget(m_searchBox);
-    m_topLayout->addWidget(m_messageWidget);
-    m_topLayout->addWidget(m_view);
-    m_topLayout->addWidget(m_filterBar);
-    m_topLayout->addWidget(m_statusBar);
+    m_topLayout->addWidget(m_searchBox, positionFor.searchBox, 0);
+    m_topLayout->addWidget(m_messageWidget, positionFor.messageWidget, 0);
+    m_topLayout->addWidget(m_view, positionFor.view, 0);
+    m_topLayout->addWidget(m_filterBar, positionFor.filterBar, 0);
+    m_topLayout->addWidget(m_statusBar, positionFor.statusBar, 0);
 
     setSearchModeEnabled(isSearchUrl(url));
 
     connect(DetailsModeSettings::self(), &KCoreConfigSkeleton::configChanged, this, [=]() {
-        if (view()->mode() == DolphinView::Mode::DetailsView) {
+        if (view()->viewMode() == DolphinView::Mode::DetailsView) {
             view()->reload();
         }
     });
@@ -357,6 +375,78 @@ void DolphinViewContainer::disconnectUrlNavigator()
     m_urlNavigatorConnected = nullptr;
 }
 
+void DolphinViewContainer::setSelectionModeEnabled(bool enabled, KActionCollection *actionCollection, SelectionModeBottomBar::Contents bottomBarContents)
+{
+    std::cout << "DolphinViewContainer::setSelectionModeEnabled(" << enabled << ", " << bottomBarContents << ")\n";
+    const bool wasEnabled = m_view->selectionMode();
+    m_view->setSelectionMode(enabled);
+
+    if (!enabled) {
+        Q_CHECK_PTR(m_selectionModeTopBar); // there is no point in disabling selectionMode when it wasn't even enabled once.
+        Q_CHECK_PTR(m_selectionModeBottomBar);
+        m_selectionModeTopBar->setVisible(false, WithAnimation);
+        m_selectionModeBottomBar->setVisible(false, WithAnimation);
+        if (wasEnabled) {
+            Q_EMIT selectionModeChanged(false);
+        }
+        return;
+    }
+
+    if (!m_selectionModeTopBar) {
+        // Changing the location will disable selection mode.
+        connect(m_urlNavigator.get(), &DolphinUrlNavigator::urlChanged, this, [this]() {
+            setSelectionModeEnabled(false);
+        });
+
+        m_selectionModeTopBar = new SelectionModeTopBar(this); // will be created hidden
+        connect(m_selectionModeTopBar, &SelectionModeTopBar::leaveSelectionModeRequested, this, [this]() {
+            setSelectionModeEnabled(false);
+        });
+        m_topLayout->addWidget(m_selectionModeTopBar, positionFor.selectionModeTopBar, 0);
+    }
+
+    if (!m_selectionModeBottomBar) {
+        m_selectionModeBottomBar = new SelectionModeBottomBar(actionCollection, this);
+        connect(m_view, &DolphinView::selectionChanged, this, [this](const KFileItemList &selection) {
+            m_selectionModeBottomBar->slotSelectionChanged(selection, m_view->url());
+        });
+        
+        connect(m_selectionModeBottomBar, &SelectionModeBottomBar::error, this, [this](const QString &errorMessage) {
+            showErrorMessage(errorMessage);
+        });
+        connect(m_selectionModeBottomBar, &SelectionModeBottomBar::leaveSelectionModeRequested, this, [this]() {
+            setSelectionModeEnabled(false);
+        });
+        m_topLayout->addWidget(m_selectionModeBottomBar, positionFor.selectionModeBottomBar, 0);
+    }
+    m_selectionModeBottomBar->resetContents(bottomBarContents);
+    if (bottomBarContents == SelectionModeBottomBar::GeneralContents) {
+        m_selectionModeBottomBar->slotSelectionChanged(m_view->selectedItems(), m_view->url());
+    }
+
+    if (!wasEnabled) {
+        m_selectionModeTopBar->setVisible(true, WithAnimation);
+        m_selectionModeBottomBar->setVisible(true, WithAnimation);
+        Q_EMIT selectionModeChanged(true);
+    }
+}
+
+bool DolphinViewContainer::isSelectionModeEnabled() const
+{
+    const bool isEnabled = m_view->selectionMode();
+    Q_ASSERT( !isEnabled // We cannot assert the invisibility of the bars because of the hide animation.
+          || ( isEnabled && m_selectionModeTopBar && m_selectionModeTopBar->isVisible() && m_selectionModeBottomBar && m_selectionModeBottomBar->isVisible()));
+    return isEnabled;
+}
+
+void DolphinViewContainer::slotSplitTabDisabled()
+{
+    if (m_selectionModeBottomBar) {
+        m_selectionModeBottomBar->slotSplitTabDisabled();
+    }
+}
+
+
 void DolphinViewContainer::showMessage(const QString& msg, MessageType type)
 {
     if (msg.isEmpty()) {