Add configurable keyboard shortcuts to select next/previous item in focused menu

src/main/kotlin/com/chylex/intellij/keyboardmaster/feature/actions/NextMenuItemAction.kt

@@ -0,0 +1,9 @@
+package com.chylex.intellij.keyboardmaster.feature.actions
+
+import javax.swing.JList
+
+class NextMenuItemAction : SelectMenuItemBaseAction() {
+	override fun updateSelection(list: JList<*>) {
+		setSelectedIndex(list, list.selectedIndex + 1)
+	}
+}

src/main/kotlin/com/chylex/intellij/keyboardmaster/feature/actions/PrevMenuItemAction.kt

@@ -0,0 +1,15 @@
+package com.chylex.intellij.keyboardmaster.feature.actions
+
+import javax.swing.JList
+
+class PrevMenuItemAction : SelectMenuItemBaseAction() {
+	override fun updateSelection(list: JList<*>) {
+		val index = list.selectedIndex
+		if (index == -1) {
+			setSelectedIndex(list, list.model.size - 1)
+		}
+		else {
+			setSelectedIndex(list, index - 1)
+		}
+	}
+}

src/main/kotlin/com/chylex/intellij/keyboardmaster/feature/actions/SelectMenuItemBaseAction.kt

@@ -0,0 +1,54 @@
+package com.chylex.intellij.keyboardmaster.feature.actions
+
+import com.intellij.codeInsight.lookup.LookupManager
+import com.intellij.codeInsight.lookup.impl.LookupImpl
+import com.intellij.ide.actions.BigPopupUI
+import com.intellij.openapi.actionSystem.AnActionEvent
+import com.intellij.openapi.actionSystem.CommonDataKeys
+import com.intellij.openapi.project.DumbAwareAction
+import com.intellij.ui.ComponentUtil
+import java.awt.KeyboardFocusManager
+import javax.swing.JList
+
+abstract class SelectMenuItemBaseAction internal constructor(): DumbAwareAction() {
+	init {
+		isEnabledInModalContext = true
+	}
+	
+	final override fun actionPerformed(e: AnActionEvent) {
+		val editor = e.getData(CommonDataKeys.EDITOR)
+		if (editor != null) {
+			val lookup = LookupManager.getActiveLookup(editor)
+			if (lookup is LookupImpl) {
+				updateSelection(lookup.list)
+				return
+			}
+		}
+		
+		var focused = KeyboardFocusManager.getCurrentKeyboardFocusManager().focusOwner
+		while (focused != null) {
+			if (focused is JList<*>) {
+				updateSelection(focused)
+				break
+			}
+			else if (focused is BigPopupUI) {
+				val list = ComponentUtil.findComponentsOfType(focused, JList::class.java).singleOrNull()
+				if (list != null) {
+					updateSelection(list)
+					break
+				}
+			}
+			
+			focused = focused.parent
+		}
+	}
+	
+	protected abstract fun updateSelection(list: JList<*>)
+	
+	protected fun setSelectedIndex(list: JList<*>, newIndex: Int) {
+		if (newIndex in 0 until list.model.size) {
+			list.selectedIndex = newIndex
+			list.ensureIndexIsVisible(newIndex)
+		}
+	}
+}

src/main/resources/META-INF/plugin.xml

@@ -8,6 +8,7 @@
     Collection of keyboard-centric additions.
     <ul>
       <li>Code completion items can be jumped to using customizable characters (numbers by default).</li>
+      <li>Keyboard shortcuts to select next/previous item in focused menu.</li>
     </ul>
   ]]></description>
   
@@ -22,4 +23,9 @@
     <applicationConfigurable parentId="tools" instance="com.chylex.intellij.keyboardmaster.configuration.PluginConfigurable" id="com.chylex.keyboardmaster" />
     <postStartupActivity implementation="com.chylex.intellij.keyboardmaster.PluginStartup" order="last" />
   </extensions>
+  
+  <actions>
+    <action id="com.chylex.intellij.keyboardmaster.feature.actions.NextMenuItemAction" class="com.chylex.intellij.keyboardmaster.feature.actions.NextMenuItemAction" text="Next Menu Item" />
+    <action id="com.chylex.intellij.keyboardmaster.feature.actions.PrevMenuItemAction" class="com.chylex.intellij.keyboardmaster.feature.actions.PrevMenuItemAction" text="Previous Menu Item" />
+  </actions>
 </idea-plugin>