fix(menu): account for keyboard already open when Menu mounts

src/components/Menu/Menu.tsx

@@ -117,6 +117,9 @@ const EASING = Easing.bezier(0.4, 0, 0.2, 1);
 
 const WINDOW_LAYOUT = Dimensions.get('window');
 
+const getKeyboardHeight = (fallback: number) =>
+  Keyboard.metrics()?.height ?? fallback;
+
 const DEFAULT_ELEVATION: Elevation = 2;
 const DEFAULT_MODE = 'elevated';
 
@@ -380,7 +383,9 @@ const Menu = ({
     });
 
     setWindowLayout({
-      height: windowLayoutResult.height - keyboardHeightRef.current,
+      height:
+        windowLayoutResult.height -
+        getKeyboardHeight(keyboardHeightRef.current),
       width: windowLayoutResult.width,
     });
 
@@ -461,6 +466,8 @@ const Menu = ({
       'keyboardDidHide',
       keyboardDidHide
     );
+    // iOS does not replay keyboardDidShow for a keyboard that is already open.
+    keyboardHeightRef.current = getKeyboardHeight(keyboardHeightRef.current);
 
     return () => {
       removeListeners();

src/components/__tests__/Menu.test.tsx

@@ -1,4 +1,4 @@
-import { Dimensions, StyleSheet, View } from 'react-native';
+import { Dimensions, Keyboard, StyleSheet, View } from 'react-native';
 
 import { expect, it, jest } from '@jest/globals';
 import { act, screen, waitFor } from '@testing-library/react-native';
@@ -234,3 +234,70 @@ it('renders menu with mode "flat"', async () => {
   expect(styles).not.toHaveProperty('shadowColor');
   expect(styles).not.toHaveProperty('shadowOpacity');
 });
+
+it('accounts for a keyboard that is already open when the menu mounts', async () => {
+  const testID = 'keyboard-aware-menu';
+  const dimensionsSpy = jest.spyOn(Dimensions, 'get').mockReturnValue({
+    width: 400,
+    height: 800,
+    scale: 2,
+    fontScale: 2,
+  });
+  const keyboardMetricsSpy = jest.spyOn(Keyboard, 'metrics').mockReturnValue({
+    screenX: 0,
+    screenY: 500,
+    width: 400,
+    height: 300,
+  });
+
+  let measureCalls = 0;
+  const measureSpy = jest
+    .spyOn(View.prototype, 'measureInWindow')
+    .mockImplementation((fn) => {
+      measureCalls += 1;
+      if (measureCalls % 2 === 1) {
+        // Menu content is tall enough to overflow the remaining window.
+        fn(100, 100, 200, 400);
+      } else {
+        fn(100, 100, 80, 32);
+      }
+    });
+
+  function makeMenu(visible: boolean) {
+    return (
+      <Portal.Host>
+        <Menu
+          visible={visible}
+          onDismiss={jest.fn()}
+          anchor={
+            <Button mode="outlined" testID="anchor">
+              Open menu
+            </Button>
+          }
+          testID={testID}
+        >
+          <Menu.Item onPress={jest.fn()} title="Undo" />
+          <Menu.Item onPress={jest.fn()} title="Redo" />
+        </Menu>
+      </Portal.Host>
+    );
+  }
+
+  const { rerender } = await render(makeMenu(false));
+
+  await act(async () => {
+    await rerender(makeMenu(true));
+    await Promise.resolve();
+  });
+
+  await waitFor(() => {
+    // eslint-disable-next-line no-restricted-syntax -- layout height is not otherwise exposed.
+    const styles = StyleSheet.flatten(screen.getByTestId(testID).props.style);
+    // Available height is window (800) minus keyboard (300) minus top (100) minus SCREEN_INDENT (8).
+    expect(styles).toEqual(expect.objectContaining({ height: 392 }));
+  });
+
+  measureSpy.mockRestore();
+  keyboardMetricsSpy.mockRestore();
+  dimensionsSpy.mockRestore();
+});