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, 18 insertions, 2 deletions

diff --git a/src/views/dolphinview.h b/src/views/dolphinview.h
index d1ecf74ba..37af97137 100644
--- a/src/views/dolphinview.h
+++ b/src/views/dolphinview.h
@@ -23,6 +23,8 @@
 #include <QUrl>
 #include <QWidget>
 
+#include <memory>
+
 typedef KIO::FileUndoManager::CommandType CommandType;
 class QVBoxLayout;
 class DolphinItemListView;
@@ -36,6 +38,7 @@ class ViewProperties;
 class QLabel;
 class QGraphicsSceneDragDropEvent;
 class QHelpEvent;
+class QProxyStyle;
 class QRegularExpression;
 
 /**
@@ -106,8 +109,11 @@ public:
      * (GeneralSettings::globalViewProps() returns false), then the
      * changed view mode will be stored automatically.
      */
-    void setMode(Mode mode);
-    Mode mode() const;
+    void setViewMode(Mode mode);
+    Mode viewMode() const;
+
+    void setSelectionMode(bool enabled);
+    bool selectionMode() const;
 
     /**
      * Turns on the file preview for the all files of the current directory,
@@ -600,6 +606,13 @@ Q_SIGNALS:
     void goForwardRequested();
 
     /**
+     * Is emitted when the selection mode is requested for the current view.
+     * This typically happens on press and hold.
+     * @see KItemListController::longPress()
+     */
+    void selectionModeRequested();
+
+    /**
      * Is emitted when the user wants to move the focus to another view.
      */
     void toggleActiveViewRequested();
@@ -916,6 +929,9 @@ private:
     QLabel* m_placeholderLabel;
     QTimer* m_showLoadingPlaceholderTimer;
 
+    /// Used for selection mode. @see setSelectionMode()
+    std::unique_ptr<QProxyStyle> m_proxyStyle;
+
     // For unit tests
     friend class TestBase;
     friend class DolphinDetailsViewTest;