TabbedPane: support Ctrl+TAB/Ctrl+Shift+TAB to switch to next/previous tab if a child of tabbedpane has focus

CHANGELOG.md

@@ -4,6 +4,8 @@ FlatLaf Change Log
 ## Unreleased
 
 - PasswordField: Warn about enabled Caps Lock.
+- TabbedPane: Support <kbd>Ctrl+TAB</kbd> / <kbd>Ctrl+Shift+TAB</kbd> to switch
+  to next / previous tab.
 - TextField, FormattedTextField and PasswordField: Support round borders (see UI
   default value `TextComponent.arc`). (issue #65)
 - IntelliJ Themes: Added Gradianto themes to demo.

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatInputMaps.java

@@ -69,7 +69,14 @@ class FlatInputMaps
 				"ctrl PAGE_DOWN", "negativeBlockIncrement",
 				"ctrl PAGE_UP", "positiveBlockIncrement"
 			);
+		}
 
+		modifyInputMap( defaults, "TabbedPane.ancestorInputMap",
+			"ctrl TAB", "navigateNext",
+			"shift ctrl TAB", "navigatePrevious"
+		);
+
+		if( !SystemInfo.IS_MAC ) {
 			modifyInputMap( defaults, "Tree.focusInputMap",
 				"ADD", "expand",
 				"SUBTRACT", "collapse"

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

@@ -26,15 +26,21 @@ import java.awt.FontMetrics;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Insets;
+import java.awt.KeyboardFocusManager;
 import java.awt.Rectangle;
 import java.awt.Shape;
+import java.awt.event.InputEvent;
+import java.awt.event.KeyEvent;
 import java.awt.geom.Path2D;
 import java.awt.geom.Rectangle2D;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
+import java.util.Collections;
+import java.util.Set;
 import javax.swing.JButton;
 import javax.swing.JComponent;
 import javax.swing.JTabbedPane;
+import javax.swing.KeyStroke;
 import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.UIResource;
@@ -90,6 +96,9 @@ import com.formdev.flatlaf.util.UIScale;
 public class FlatTabbedPaneUI
 	extends BasicTabbedPaneUI
 {
+	private static Set<KeyStroke> focusForwardTraversalKeys;
+	private static Set<KeyStroke> focusBackwardTraversalKeys;
+
 	protected Color disabledForeground;
 	protected Color selectedBackground;
 	protected Color selectedForeground;
@@ -142,11 +151,27 @@ public class FlatTabbedPaneUI
 		tabHeight = scale( tabHeight );
 		tabSelectionHeight = scale( tabSelectionHeight );
 
+		// replace focus forward/backward traversal keys with TAB/Shift+TAB because
+		// the default also includes Ctrl+TAB/Ctrl+Shift+TAB, which we need to switch tabs
+		if( focusForwardTraversalKeys == null ) {
+			focusForwardTraversalKeys = Collections.singleton( KeyStroke.getKeyStroke( KeyEvent.VK_TAB, 0 ) );
+			focusBackwardTraversalKeys = Collections.singleton( KeyStroke.getKeyStroke( KeyEvent.VK_TAB, InputEvent.SHIFT_MASK ) );
+		}
+		// Ideally we should use `LookAndFeel.installProperty( tabPane, "focusTraversalKeysForward", keys )` here
+		// instead of `tabPane.setFocusTraversalKeys()`, but WindowsTabbedPaneUI also uses later method
+		// and switching from Windows LaF to FlatLaf would not replace the keys and Ctrl+TAB would not work.
+		tabPane.setFocusTraversalKeys( KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, focusForwardTraversalKeys );
+		tabPane.setFocusTraversalKeys( KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, focusBackwardTraversalKeys );
+
 		MigLayoutVisualPadding.install( tabPane, null );
 	}
 
 	@Override
 	protected void uninstallDefaults() {
+		// restore focus forward/backward traversal keys
+		tabPane.setFocusTraversalKeys( KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, null );
+		tabPane.setFocusTraversalKeys( KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, null );
+
 		super.uninstallDefaults();
 
 		disabledForeground = null;

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatContainerTest.java

@@ -81,7 +81,11 @@ public class FlatContainerTest
 		JSplitPane splitPane3 = new JSplitPane();
 		JSplitPane splitPane1 = new JSplitPane();
 		JPanel panel10 = new JPanel();
+		JTextField textField2 = new JTextField();
+		JButton button1 = new JButton();
 		JPanel panel11 = new JPanel();
+		JTextField textField3 = new JTextField();
+		JButton button2 = new JButton();
 		JSplitPane splitPane2 = new JSplitPane();
 		JPanel panel12 = new JPanel();
 		JPanel panel13 = new JPanel();
@@ -89,7 +93,11 @@ public class FlatContainerTest
 		tabbedPane1 = new JTabbedPane();
 		JPanel panel1 = new JPanel();
 		JLabel label1 = new JLabel();
+		JTextField textField4 = new JTextField();
+		JButton button3 = new JButton();
 		JPanel panel2 = new JPanel();
+		JTextField textField5 = new JTextField();
+		JButton button4 = new JButton();
 		JLabel label2 = new JLabel();
 		tabbedPane3 = new JTabbedPane();
 		JPanel panel5 = new JPanel();
@@ -145,6 +153,14 @@ public class FlatContainerTest
 					{
 						panel10.setBackground(Color.orange);
 						panel10.setLayout(new FlowLayout());
+
+						//---- textField2 ----
+						textField2.setText("some text");
+						panel10.add(textField2);
+
+						//---- button1 ----
+						button1.setText("...");
+						panel10.add(button1);
 					}
 					splitPane1.setLeftComponent(panel10);
 
@@ -152,6 +168,14 @@ public class FlatContainerTest
 					{
 						panel11.setBackground(Color.magenta);
 						panel11.setLayout(new FlowLayout());
+
+						//---- textField3 ----
+						textField3.setText("some text");
+						panel11.add(textField3);
+
+						//---- button2 ----
+						button2.setText("...");
+						panel11.add(button2);
 					}
 					splitPane1.setRightComponent(panel11);
 				}
@@ -195,6 +219,14 @@ public class FlatContainerTest
 					//---- label1 ----
 					label1.setText("TOP");
 					panel1.add(label1);
+
+					//---- textField4 ----
+					textField4.setText("some text");
+					panel1.add(textField4);
+
+					//---- button3 ----
+					button3.setText("...");
+					panel1.add(button3);
 				}
 				tabbedPane1.addTab("Tab 1", panel1);
 
@@ -202,6 +234,14 @@ public class FlatContainerTest
 				{
 					panel2.setBorder(new LineBorder(Color.magenta));
 					panel2.setLayout(new FlowLayout());
+
+					//---- textField5 ----
+					textField5.setText("some text");
+					panel2.add(textField5);
+
+					//---- button4 ----
+					button4.setText("...");
+					panel2.add(button4);
 				}
 				tabbedPane1.addTab("Tab 2", panel2);
 

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatContainerTest.jfd

@@ -1,4 +1,4 @@
-JFDML JFormDesigner: "7.0.0.0.194" Java: "11.0.2" encoding: "UTF-8"
+JFDML JFormDesigner: "7.0.1.0.272" Java: "13.0.1" encoding: "UTF-8"
 
 new FormModel {
 	contentType: "form/swing"
@@ -32,12 +32,28 @@ new FormModel {
 						add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class java.awt.FlowLayout ) ) {
 							name: "panel10"
 							"background": sfield java.awt.Color orange
+							add( new FormComponent( "javax.swing.JTextField" ) {
+								name: "textField2"
+								"text": "some text"
+							} )
+							add( new FormComponent( "javax.swing.JButton" ) {
+								name: "button1"
+								"text": "..."
+							} )
 						}, new FormLayoutConstraints( class java.lang.String ) {
 							"value": "left"
 						} )
 						add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class java.awt.FlowLayout ) ) {
 							name: "panel11"
 							"background": sfield java.awt.Color magenta
+							add( new FormComponent( "javax.swing.JTextField" ) {
+								name: "textField3"
+								"text": "some text"
+							} )
+							add( new FormComponent( "javax.swing.JButton" ) {
+								name: "button2"
+								"text": "..."
+							} )
 						}, new FormLayoutConstraints( class java.lang.String ) {
 							"value": "right"
 						} )
@@ -86,12 +102,28 @@ new FormModel {
 							name: "label1"
 							"text": "TOP"
 						} )
+						add( new FormComponent( "javax.swing.JTextField" ) {
+							name: "textField4"
+							"text": "some text"
+						} )
+						add( new FormComponent( "javax.swing.JButton" ) {
+							name: "button3"
+							"text": "..."
+						} )
 					}, new FormLayoutConstraints( null ) {
 						"title": "Tab 1"
 					} )
 					add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class java.awt.FlowLayout ) ) {
 						name: "panel2"
 						"border": &LineBorder0 new javax.swing.border.LineBorder( sfield java.awt.Color magenta, 1, false )
+						add( new FormComponent( "javax.swing.JTextField" ) {
+							name: "textField5"
+							"text": "some text"
+						} )
+						add( new FormComponent( "javax.swing.JButton" ) {
+							name: "button4"
+							"text": "..."
+						} )
 					}, new FormLayoutConstraints( null ) {
 						"title": "Tab 2"
 					} )

flatlaf-testing/src/main/resources/com/formdev/flatlaf/testing/uidefaults/FlatLightLaf_InputMap_1.8.0_202-mac.txt

@@ -536,11 +536,13 @@ SplitPane.ancestorInputMap     [lazy] 14    javax.swing.plaf.InputMapUIResource
 
 #---- TabbedPane ----
 
-TabbedPane.ancestorInputMap    [lazy] 4    javax.swing.plaf.InputMapUIResource [UI]
+TabbedPane.ancestorInputMap    [lazy] 6    javax.swing.plaf.InputMapUIResource [UI]
     ctrl KP_UP            requestFocus
     ctrl PAGE_DOWN        navigatePageDown
     ctrl PAGE_UP          navigatePageUp
+    ctrl TAB              navigateNext
     ctrl UP               requestFocus
+    shift ctrl TAB        navigatePrevious
 TabbedPane.focusInputMap       [lazy] 10    javax.swing.plaf.InputMapUIResource [UI]
     ctrl DOWN             requestFocusForVisibleComponent
     ctrl KP_DOWN          requestFocusForVisibleComponent

flatlaf-testing/src/main/resources/com/formdev/flatlaf/testing/uidefaults/FlatLightLaf_InputMap_1.8.0_202.txt

@@ -475,11 +475,13 @@ SplitPane.ancestorInputMap     [lazy] 14    javax.swing.plaf.InputMapUIResource
 
 #---- TabbedPane ----
 
-TabbedPane.ancestorInputMap    [lazy] 4    javax.swing.plaf.InputMapUIResource [UI]
+TabbedPane.ancestorInputMap    [lazy] 6    javax.swing.plaf.InputMapUIResource [UI]
     ctrl KP_UP            requestFocus
     ctrl PAGE_DOWN        navigatePageDown
     ctrl PAGE_UP          navigatePageUp
+    ctrl TAB              navigateNext
     ctrl UP               requestFocus
+    shift ctrl TAB        navigatePrevious
 TabbedPane.focusInputMap       [lazy] 10    javax.swing.plaf.InputMapUIResource [UI]
     ctrl DOWN             requestFocusForVisibleComponent
     ctrl KP_DOWN          requestFocusForVisibleComponent