Add "On Application State" node

Sources/armory/logicnode/OnApplicationStateNode.hx

@@ -0,0 +1,20 @@
+package armory.logicnode;
+
+@:access(iron.Trait)
+class OnApplicationStateNode extends LogicNode {
+
+	public function new(tree: LogicTree) {
+		super(tree);
+		tree.notifyOnInit(init);
+	}
+
+	function init() {
+		kha.System.notifyOnApplicationState(
+			() -> runOutput(0), // On foreground
+			null, // On resume
+			null, // On pause
+			() -> runOutput(1), // On background
+			() -> runOutput(2) // On shutdown
+		);
+	}
+}

blender/arm/logicnode/event/LN_on_application_state.py

@@ -0,0 +1,17 @@
+from arm.logicnode.arm_nodes import *
+
+
+class OnApplicationStateNode(ArmLogicTreeNode):
+    """Listen to different application state changes."""
+    bl_idname = 'LNOnApplicationStateNode'
+    bl_label = 'On Application State'
+    arm_version = 1
+
+    def init(self, context):
+        super().init(context)
+        self.add_output('ArmNodeSocketAction', 'On Foreground')
+        self.add_output('ArmNodeSocketAction', 'On Background')
+        self.add_output('ArmNodeSocketAction', 'On Shutdown')
+
+
+add_node(OnApplicationStateNode, category=PKG_AS_CATEGORY)