SplitPane: added tooltips to expand/collapse buttons (issue #198)

CHANGELOG.md

@@ -36,7 +36,8 @@ FlatLaf Change Log
   `TitlePane.borderColor`). (issue #184)
 - Extras: `FlatSVGIcon` now allows specifying icon width and height in
   constructors. (issue #196)
-- SplitPane: Hide not applicable expand/collapse buttons. (issue #198)
+- SplitPane: Hide not applicable expand/collapse buttons. Added tooltips to
+  expand/collapse buttons. (issue #198)
 
 
 #### Fixed bugs

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatSplitPaneUI.java

@@ -20,11 +20,13 @@ import java.awt.Color;
 import java.awt.Container;
 import java.awt.Cursor;
 import java.awt.Insets;
+import java.awt.event.MouseEvent;
 import java.beans.PropertyChangeEvent;
 import javax.swing.JButton;
 import javax.swing.JComponent;
 import javax.swing.JSplitPane;
 import javax.swing.SwingConstants;
+import javax.swing.ToolTipManager;
 import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicSplitPaneDivider;
@@ -152,6 +154,7 @@ public class FlatSplitPaneUI
 			protected FlatOneTouchButton( boolean left ) {
 				super( SwingConstants.NORTH, arrowType, oneTouchArrowColor, null, oneTouchHoverArrowColor, null );
 				setCursor( Cursor.getPredefinedCursor( Cursor.DEFAULT_CURSOR ) );
+				ToolTipManager.sharedInstance().registerComponent( this );
 
 				this.left = left;
 			}
@@ -162,6 +165,26 @@ public class FlatSplitPaneUI
 					? (left ? SwingConstants.NORTH : SwingConstants.SOUTH)
 					: (left ? SwingConstants.WEST : SwingConstants.EAST);
 			}
+
+			@Override
+			public String getToolTipText( MouseEvent e ) {
+				String key = (orientation == JSplitPane.VERTICAL_SPLIT)
+					? (left
+						? (isRightCollapsed()
+							? "SplitPaneDivider.expandBottomToolTipText"
+							: "SplitPaneDivider.collapseTopToolTipText")
+						: (isLeftCollapsed()
+							? "SplitPaneDivider.expandTopToolTipText"
+							: "SplitPaneDivider.collapseBottomToolTipText"))
+					: (left
+						? (isRightCollapsed()
+							? "SplitPaneDivider.expandRightToolTipText"
+							: "SplitPaneDivider.collapseLeftToolTipText")
+						: (isLeftCollapsed()
+							? "SplitPaneDivider.expandLeftToolTipText"
+							: "SplitPaneDivider.collapseRightToolTipText"));
+				return UIManager.getString( key, getLocale() );
+			}
 		}
 
 		//---- class FlatDividerLayout ----------------------------------------

flatlaf-core/src/main/resources/com/formdev/flatlaf/resources/Bundle.properties

@@ -48,6 +48,18 @@ FileChooser.listViewActionLabelText=List
 FileChooser.detailsViewActionLabelText=Details
 
 
+#---- SplitPaneDivider ----
+
+SplitPaneDivider.collapseLeftToolTipText=Collapse Left Pane
+SplitPaneDivider.collapseRightToolTipText=Collapse Right Pane
+SplitPaneDivider.collapseTopToolTipText=Collapse Top Pane
+SplitPaneDivider.collapseBottomToolTipText=Collapse Bottom Pane
+SplitPaneDivider.expandLeftToolTipText=Expand Left Pane
+SplitPaneDivider.expandRightToolTipText=Expand Right Pane
+SplitPaneDivider.expandTopToolTipText=Expand Top Pane
+SplitPaneDivider.expandBottomToolTipText=Expand Bottom Pane
+
+
 #---- TabbedPane ----
 
 TabbedPane.moreTabsButtonToolTipText=Show Hidden Tabs