Clarify state names for IME Switcher button

We had a few instances of properties referencing the IME Switcher or its
visibility, when in fact this was related to the button, not the menu.

This clarifies the names for these states, as well as adding some
documentation around where these values are used/passed.

Flag: EXEMPT bugfix
Bug: 366129400
Test: n/a
Change-Id: Ia75cdbfcd0cf4642bc747a132c8500908c869885

14 files changed, 188 insertions, 92 deletions

diff --git a/core/java/android/app/StatusBarManager.java b/core/java/android/app/StatusBarManager.java
index b7285c38290c..7454c44997d6 100644
--- a/core/java/android/app/StatusBarManager.java
+++ b/core/java/android/app/StatusBarManager.java
@@ -60,6 +60,7 @@ import com.android.internal.statusbar.NotificationVisibility;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -195,12 +196,40 @@ public class StatusBarManager {
      */
     private static final int DEFAULT_SIM_LOCKED_DISABLED_FLAGS = DISABLE_EXPAND;
 
-    /** @hide */
-    public static final int NAVIGATION_HINT_BACK_ALT      = 1 << 0;
-    /** @hide */
-    public static final int NAVIGATION_HINT_IME_SHOWN     = 1 << 1;
-    /** @hide */
-    public static final int NAVIGATION_HINT_IME_SWITCHER_SHOWN = 1 << 2;
+    /**
+     * The back button is visually adjusted to indicate that it will dismiss the IME when pressed.
+     * This only takes effect while the IME is visible. By default, it is set while the IME is
+     * visible, but may be overridden by the
+     * {@link android.inputmethodservice.InputMethodService.BackDispositionMode backDispositionMode}
+     * set by the IME.
+     *
+     * @hide
+     */
+    public static final int NAVIGATION_HINT_BACK_ALT = 1 << 0;
+    /**
+     * The IME is visible.
+     *
+     * @hide
+     */
+    public static final int NAVIGATION_HINT_IME_SHOWN = 1 << 1;
+    /**
+     * The IME Switcher button is visible. This only takes effect while the IME is visible.
+     *
+     * @hide
+     */
+    public static final int NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN = 1 << 2;
+    /**
+     * Navigation bar flags related to the IME state.
+     *
+     * @hide
+     */
+    @IntDef(flag = true, prefix = { "NAVIGATION_HINT_" }, value = {
+            NAVIGATION_HINT_BACK_ALT,
+            NAVIGATION_HINT_IME_SHOWN,
+            NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN,
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface NavigationHint {}
 
     /** @hide */
     public static final int WINDOW_STATUS_BAR = 1;
@@ -1325,6 +1354,22 @@ public class StatusBarManager {
     }
 
     /** @hide */
+    @NonNull
+    public static String navigationHintsToString(@NavigationHint int hints) {
+        final var hintStrings = new ArrayList<String>();
+        if ((hints & NAVIGATION_HINT_BACK_ALT) != 0) {
+            hintStrings.add("NAVIGATION_HINT_BACK_ALT");
+        }
+        if ((hints & NAVIGATION_HINT_IME_SHOWN) != 0) {
+            hintStrings.add("NAVIGATION_HINT_IME_SHOWN");
+        }
+        if ((hints & NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN) != 0) {
+            hintStrings.add("NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN");
+        }
+        return String.join(" | ", hintStrings);
+    }
+
+    /** @hide */
     public static String windowStateToString(int state) {
         if (state == WINDOW_STATE_HIDING) return "WINDOW_STATE_HIDING";
         if (state == WINDOW_STATE_HIDDEN) return "WINDOW_STATE_HIDDEN";
diff --git a/core/java/android/inputmethodservice/NavigationBarController.java b/core/java/android/inputmethodservice/NavigationBarController.java
index 019ba0045916..edc5cb7cdf6a 100644
--- a/core/java/android/inputmethodservice/NavigationBarController.java
+++ b/core/java/android/inputmethodservice/NavigationBarController.java
@@ -18,7 +18,7 @@ package android.inputmethodservice;
 
 import static android.app.StatusBarManager.NAVIGATION_HINT_BACK_ALT;
 import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SHOWN;
-import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_SHOWN;
+import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN;
 import static android.view.WindowInsets.Type.captionBar;
 import static android.view.WindowInsetsController.APPEARANCE_LIGHT_NAVIGATION_BARS;
 
@@ -245,7 +245,7 @@ final class NavigationBarController {
                     // TODO(b/213337792): Set NAVIGATION_HINT_IME_SHOWN only when necessary.
                     final int hints = NAVIGATION_HINT_BACK_ALT | NAVIGATION_HINT_IME_SHOWN
                             | (mShouldShowImeSwitcherWhenImeIsShown
-                                    ? NAVIGATION_HINT_IME_SWITCHER_SHOWN : 0);
+                                    ? NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN : 0);
                     navigationBarView.setNavigationIconHints(hints);
                     navigationBarView.prepareNavButtons(this);
                 }
@@ -518,7 +518,7 @@ final class NavigationBarController {
                     // TODO(b/213337792): Set NAVIGATION_HINT_IME_SHOWN only when necessary.
                     final int hints = NAVIGATION_HINT_BACK_ALT | NAVIGATION_HINT_IME_SHOWN
                             | (mShouldShowImeSwitcherWhenImeIsShown
-                                    ? NAVIGATION_HINT_IME_SWITCHER_SHOWN : 0);
+                                    ? NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN : 0);
                     navigationBarView.setNavigationIconHints(hints);
                 }
             } else {
diff --git a/core/java/android/inputmethodservice/navigationbar/NavigationBarView.java b/core/java/android/inputmethodservice/navigationbar/NavigationBarView.java
index e7e46a9482c8..622d5d1b1c5a 100644
--- a/core/java/android/inputmethodservice/navigationbar/NavigationBarView.java
+++ b/core/java/android/inputmethodservice/navigationbar/NavigationBarView.java
@@ -16,6 +16,8 @@
 
 package android.inputmethodservice.navigationbar;
 
+import static android.app.StatusBarManager.NAVIGATION_HINT_BACK_ALT;
+import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN;
 import static android.inputmethodservice.navigationbar.NavigationBarConstants.DARK_MODE_ICON_COLOR_SINGLE_TONE;
 import static android.inputmethodservice.navigationbar.NavigationBarConstants.LIGHT_MODE_ICON_COLOR_SINGLE_TONE;
 import static android.inputmethodservice.navigationbar.NavigationBarConstants.NAVBAR_BACK_BUTTON_IME_OFFSET;
@@ -28,6 +30,7 @@ import android.annotation.DrawableRes;
 import android.annotation.FloatRange;
 import android.annotation.NonNull;
 import android.app.StatusBarManager;
+import android.app.StatusBarManager.NavigationHint;
 import android.content.Context;
 import android.content.res.Configuration;
 import android.graphics.Canvas;
@@ -63,7 +66,8 @@ public final class NavigationBarView extends FrameLayout {
     private int mCurrentRotation = -1;
 
     int mDisabledFlags = 0;
-    int mNavigationIconHints = StatusBarManager.NAVIGATION_HINT_BACK_ALT;
+    @NavigationHint
+    private int mNavigationIconHints = 0;
     private final int mNavBarMode = NAV_BAR_MODE_GESTURAL;
 
     private KeyButtonDrawable mBackIcon;
@@ -241,8 +245,7 @@ public final class NavigationBarView extends FrameLayout {
     }
 
     private void orientBackButton(KeyButtonDrawable drawable) {
-        final boolean useAltBack =
-                (mNavigationIconHints & StatusBarManager.NAVIGATION_HINT_BACK_ALT) != 0;
+        final boolean useAltBack = (mNavigationIconHints & NAVIGATION_HINT_BACK_ALT) != 0;
         final boolean isRtl = mConfiguration.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL;
         float degrees = useAltBack ? (isRtl ? 90 : -90) : 0;
         if (drawable.getRotation() == degrees) {
@@ -284,8 +287,10 @@ public final class NavigationBarView extends FrameLayout {
      *
      * @param hints bit flags defined in {@link StatusBarManager}.
      */
-    public void setNavigationIconHints(int hints) {
-        if (hints == mNavigationIconHints) return;
+    public void setNavigationIconHints(@NavigationHint int hints) {
+        if (hints == mNavigationIconHints) {
+            return;
+        }
         final boolean newBackAlt = (hints & StatusBarManager.NAVIGATION_HINT_BACK_ALT) != 0;
         final boolean oldBackAlt =
                 (mNavigationIconHints & StatusBarManager.NAVIGATION_HINT_BACK_ALT) != 0;
@@ -312,9 +317,10 @@ public final class NavigationBarView extends FrameLayout {
         getImeSwitchButton().setImageDrawable(mImeSwitcherIcon);
 
         // Update IME button visibility, a11y and rotate button always overrides the appearance
-        final boolean imeSwitcherVisible =
-                (mNavigationIconHints & StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_SHOWN) != 0;
-        getImeSwitchButton().setVisibility(imeSwitcherVisible ? View.VISIBLE : View.INVISIBLE);
+        final boolean isImeSwitcherButtonVisible =
+                (mNavigationIconHints & NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN) != 0;
+        getImeSwitchButton()
+                .setVisibility(isImeSwitcherButtonVisible ? View.VISIBLE : View.INVISIBLE);
 
         getBackButton().setVisibility(View.VISIBLE);
         getHomeHandle().setVisibility(View.INVISIBLE);
diff --git a/core/java/com/android/internal/statusbar/IStatusBar.aidl b/core/java/com/android/internal/statusbar/IStatusBar.aidl
index 555374a05592..035501ca4479 100644
--- a/core/java/com/android/internal/statusbar/IStatusBar.aidl
+++ b/core/java/com/android/internal/statusbar/IStatusBar.aidl
@@ -51,6 +51,14 @@ oneway interface IStatusBar
 
     void showWirelessChargingAnimation(int batteryLevel);
 
+    /**
+     * Sets the new IME window status.
+     *
+     * @param displayId The id of the display to which the IME is bound.
+     * @param vis The IME window visibility.
+     * @param backDisposition The IME back disposition mode.
+     * @param showImeSwitcher Whether the IME Switcher button should be shown.
+     */
     void setImeWindowStatus(int displayId, int vis, int backDisposition, boolean showImeSwitcher);
     void setWindowState(int display, int window, int state);
 
diff --git a/core/java/com/android/internal/statusbar/IStatusBarService.aidl b/core/java/com/android/internal/statusbar/IStatusBarService.aidl
index f14e1f63cdf6..20d274c77a69 100644
--- a/core/java/com/android/internal/statusbar/IStatusBarService.aidl
+++ b/core/java/com/android/internal/statusbar/IStatusBarService.aidl
@@ -61,6 +61,14 @@ interface IStatusBarService
     void setIconVisibility(String slot, boolean visible);
     @UnsupportedAppUsage
     void removeIcon(String slot);
+    /**
+     * Sets the new IME window status.
+     *
+     * @param displayId The id of the display to which the IME is bound.
+     * @param vis The IME window visibility.
+     * @param backDisposition The IME back disposition mode.
+     * @param showImeSwitcher Whether the IME Switcher button should be shown.
+     */
     void setImeWindowStatus(int displayId, int vis, int backDisposition, boolean showImeSwitcher);
     void expandSettingsPanel(String subPanel);
 
diff --git a/packages/SystemUI/multivalentTests/src/com/android/systemui/navigationbar/views/NavigationBarTest.java b/packages/SystemUI/multivalentTests/src/com/android/systemui/navigationbar/views/NavigationBarTest.java
index 7f9313cbeb5b..83b68fed768e 100644
--- a/packages/SystemUI/multivalentTests/src/com/android/systemui/navigationbar/views/NavigationBarTest.java
+++ b/packages/SystemUI/multivalentTests/src/com/android/systemui/navigationbar/views/NavigationBarTest.java
@@ -18,7 +18,7 @@ package com.android.systemui.navigationbar.views;
 
 import static android.app.StatusBarManager.NAVIGATION_HINT_BACK_ALT;
 import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SHOWN;
-import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_SHOWN;
+import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN;
 import static android.inputmethodservice.InputMethodService.BACK_DISPOSITION_ADJUST_NOTHING;
 import static android.inputmethodservice.InputMethodService.BACK_DISPOSITION_DEFAULT;
 import static android.inputmethodservice.InputMethodService.IME_VISIBLE;
@@ -32,7 +32,7 @@ import static com.android.systemui.navigationbar.views.NavigationBar.NavBarActio
 import static com.android.systemui.navigationbar.views.buttons.KeyButtonView.NavBarButtonEvent.NAVBAR_IME_SWITCHER_BUTTON_LONGPRESS;
 import static com.android.systemui.navigationbar.views.buttons.KeyButtonView.NavBarButtonEvent.NAVBAR_IME_SWITCHER_BUTTON_TAP;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_IME_SHOWING;
-import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_IME_SWITCHER_SHOWING;
+import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_SCREEN_PINNING;
 
 import static com.google.common.truth.Truth.assertThat;
@@ -501,7 +501,7 @@ public class NavigationBarTest extends SysuiTestCase {
         mNavigationBar.setImeWindowStatus(DEFAULT_DISPLAY, IME_VISIBLE,
                 BACK_DISPOSITION_DEFAULT, true /* showImeSwitcher */);
         verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SHOWING), eq(true));
-        verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SWITCHER_SHOWING), eq(true));
+        verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING), eq(true));
     }
 
     /**
@@ -515,7 +515,7 @@ public class NavigationBarTest extends SysuiTestCase {
         mNavigationBar.setImeWindowStatus(DEFAULT_DISPLAY, IME_VISIBLE,
                 BACK_DISPOSITION_DEFAULT, false /* showImeSwitcher */);
         verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SHOWING), eq(true));
-        verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SWITCHER_SHOWING), eq(false));
+        verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING), eq(false));
     }
 
     /**
@@ -532,7 +532,7 @@ public class NavigationBarTest extends SysuiTestCase {
         mNavigationBar.setImeWindowStatus(DEFAULT_DISPLAY, 0 /* vis */,
                 BACK_DISPOSITION_DEFAULT, true /* showImeSwitcher */);
         verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SHOWING), eq(false));
-        verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SWITCHER_SHOWING), eq(false));
+        verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING), eq(false));
     }
 
     /**
@@ -546,7 +546,7 @@ public class NavigationBarTest extends SysuiTestCase {
         mNavigationBar.setImeWindowStatus(DEFAULT_DISPLAY, IME_VISIBLE,
                 BACK_DISPOSITION_ADJUST_NOTHING, true /* showImeSwitcher */);
         verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SHOWING), eq(true));
-        verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SWITCHER_SHOWING), eq(true));
+        verify(mMockSysUiState).setFlag(eq(SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING), eq(true));
     }
 
     @Test
@@ -568,12 +568,12 @@ public class NavigationBarTest extends SysuiTestCase {
 
         // Verify IME window state will be updated in default NavBar & external NavBar state reset.
         assertEquals(NAVIGATION_HINT_BACK_ALT | NAVIGATION_HINT_IME_SHOWN
-                        | NAVIGATION_HINT_IME_SWITCHER_SHOWN,
+                        | NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN,
                 defaultNavBar.getNavigationIconHints());
         assertFalse((externalNavBar.getNavigationIconHints() & NAVIGATION_HINT_BACK_ALT) != 0);
         assertFalse((externalNavBar.getNavigationIconHints() & NAVIGATION_HINT_IME_SHOWN) != 0);
-        assertFalse((externalNavBar.getNavigationIconHints() & NAVIGATION_HINT_IME_SWITCHER_SHOWN)
-                != 0);
+        assertFalse((externalNavBar.getNavigationIconHints()
+                & NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN) != 0);
 
         externalNavBar.setImeWindowStatus(EXTERNAL_DISPLAY_ID, IME_VISIBLE,
                 BACK_DISPOSITION_DEFAULT, true);
@@ -581,12 +581,12 @@ public class NavigationBarTest extends SysuiTestCase {
                 BACK_DISPOSITION_DEFAULT, false);
         // Verify IME window state will be updated in external NavBar & default NavBar state reset.
         assertEquals(NAVIGATION_HINT_BACK_ALT | NAVIGATION_HINT_IME_SHOWN
-                        | NAVIGATION_HINT_IME_SWITCHER_SHOWN,
+                        | NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN,
                 externalNavBar.getNavigationIconHints());
         assertFalse((defaultNavBar.getNavigationIconHints() & NAVIGATION_HINT_BACK_ALT) != 0);
         assertFalse((defaultNavBar.getNavigationIconHints() & NAVIGATION_HINT_IME_SHOWN) != 0);
-        assertFalse((defaultNavBar.getNavigationIconHints() & NAVIGATION_HINT_IME_SWITCHER_SHOWN)
-                != 0);
+        assertFalse((defaultNavBar.getNavigationIconHints()
+                & NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN) != 0);
     }
 
     @Test
@@ -604,8 +604,8 @@ public class NavigationBarTest extends SysuiTestCase {
                 BACK_DISPOSITION_DEFAULT, true);
         assertTrue((mNavigationBar.getNavigationIconHints() & NAVIGATION_HINT_BACK_ALT) != 0);
         assertTrue((mNavigationBar.getNavigationIconHints() & NAVIGATION_HINT_IME_SHOWN) != 0);
-        assertTrue((mNavigationBar.getNavigationIconHints() & NAVIGATION_HINT_IME_SWITCHER_SHOWN)
-                != 0);
+        assertTrue((mNavigationBar.getNavigationIconHints()
+                & NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN) != 0);
 
         // Verify navbar didn't alter and showing back icon when the keyguard is showing without
         // requesting IME insets visible.
@@ -614,8 +614,8 @@ public class NavigationBarTest extends SysuiTestCase {
                 BACK_DISPOSITION_DEFAULT, true);
         assertFalse((mNavigationBar.getNavigationIconHints() & NAVIGATION_HINT_BACK_ALT) != 0);
         assertFalse((mNavigationBar.getNavigationIconHints() & NAVIGATION_HINT_IME_SHOWN) != 0);
-        assertFalse((mNavigationBar.getNavigationIconHints() & NAVIGATION_HINT_IME_SWITCHER_SHOWN)
-                != 0);
+        assertFalse((mNavigationBar.getNavigationIconHints()
+                & NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN) != 0);
 
         // Verify navbar altered and showing back icon when the keyguard is showing and
         // requesting IME insets visible.
@@ -625,8 +625,8 @@ public class NavigationBarTest extends SysuiTestCase {
                 BACK_DISPOSITION_DEFAULT, true);
         assertTrue((mNavigationBar.getNavigationIconHints() & NAVIGATION_HINT_BACK_ALT) != 0);
         assertTrue((mNavigationBar.getNavigationIconHints() & NAVIGATION_HINT_IME_SHOWN) != 0);
-        assertTrue((mNavigationBar.getNavigationIconHints() & NAVIGATION_HINT_IME_SWITCHER_SHOWN)
-                != 0);
+        assertTrue((mNavigationBar.getNavigationIconHints()
+                & NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN) != 0);
     }
 
     @Test
diff --git a/packages/SystemUI/shared/src/com/android/systemui/shared/recents/utilities/Utilities.java b/packages/SystemUI/shared/src/com/android/systemui/shared/recents/utilities/Utilities.java
index 41ad4373455e..818e39800b0c 100644
--- a/packages/SystemUI/shared/src/com/android/systemui/shared/recents/utilities/Utilities.java
+++ b/packages/SystemUI/shared/src/com/android/systemui/shared/recents/utilities/Utilities.java
@@ -18,9 +18,10 @@ package com.android.systemui.shared.recents.utilities;
 
 import static android.app.StatusBarManager.NAVIGATION_HINT_BACK_ALT;
 import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SHOWN;
-import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_SHOWN;
+import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN;
 
 import android.annotation.TargetApi;
+import android.app.StatusBarManager.NavigationHint;
 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Color;
@@ -103,10 +104,15 @@ public class Utilities {
     }
 
     /**
-     * @return updated set of flags from InputMethodService based off {@param oldHints}
-     *          Leaves original hints unmodified
+     * Gets the updated navigation icon hints, based on the current ones and the given IME state.
+     *
+     * @param oldHints        current navigation icon hints.
+     * @param backDisposition the IME back disposition mode.
+     * @param imeShown        whether the IME is currently visible.
+     * @param showImeSwitcher whether the IME Switcher button should be shown.
      */
-    public static int calculateBackDispositionHints(int oldHints,
+    @NavigationHint
+    public static int calculateNavigationIconHints(@NavigationHint int oldHints,
             @BackDispositionMode int backDisposition, boolean imeShown, boolean showImeSwitcher) {
         int hints = oldHints;
         switch (backDisposition) {
@@ -129,9 +135,9 @@ public class Utilities {
             hints &= ~NAVIGATION_HINT_IME_SHOWN;
         }
         if (showImeSwitcher) {
-            hints |= NAVIGATION_HINT_IME_SWITCHER_SHOWN;
+            hints |= NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN;
         } else {
-            hints &= ~NAVIGATION_HINT_IME_SWITCHER_SHOWN;
+            hints &= ~NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN;
         }
 
         return hints;
diff --git a/packages/SystemUI/shared/src/com/android/systemui/shared/system/QuickStepContract.java b/packages/SystemUI/shared/src/com/android/systemui/shared/system/QuickStepContract.java
index 6f13d637d5c5..f87d9b05d795 100644
--- a/packages/SystemUI/shared/src/com/android/systemui/shared/system/QuickStepContract.java
+++ b/packages/SystemUI/shared/src/com/android/systemui/shared/system/QuickStepContract.java
@@ -98,12 +98,12 @@ public class QuickStepContract {
     public static final long SYSUI_STATE_ONE_HANDED_ACTIVE = 1L << 16;
     // Allow system gesture no matter the system bar(s) is visible or not
     public static final long SYSUI_STATE_ALLOW_GESTURE_IGNORING_BAR_VISIBILITY = 1L << 17;
-    // The IME is showing
+    // The IME is visible.
     public static final long SYSUI_STATE_IME_SHOWING = 1L << 18;
     // The window magnification is overlapped with system gesture insets at the bottom.
     public static final long SYSUI_STATE_MAGNIFICATION_OVERLAP = 1L << 19;
-    // ImeSwitcher is showing
-    public static final long SYSUI_STATE_IME_SWITCHER_SHOWING = 1L << 20;
+    // The IME Switcher button is visible.
+    public static final long SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING = 1L << 20;
     // Device dozing/AOD state
     public static final long SYSUI_STATE_DEVICE_DOZING = 1L << 21;
     // The home feature is disabled (either by SUW/SysUI/device policy)
@@ -170,7 +170,7 @@ public class QuickStepContract {
             SYSUI_STATE_ALLOW_GESTURE_IGNORING_BAR_VISIBILITY,
             SYSUI_STATE_IME_SHOWING,
             SYSUI_STATE_MAGNIFICATION_OVERLAP,
-            SYSUI_STATE_IME_SWITCHER_SHOWING,
+            SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING,
             SYSUI_STATE_DEVICE_DOZING,
             SYSUI_STATE_BACK_DISABLED,
             SYSUI_STATE_BUBBLES_MANAGE_MENU_EXPANDED,
@@ -250,8 +250,8 @@ public class QuickStepContract {
         if ((flags & SYSUI_STATE_MAGNIFICATION_OVERLAP) != 0) {
             str.add("magnification_overlap");
         }
-        if ((flags & SYSUI_STATE_IME_SWITCHER_SHOWING) != 0) {
-            str.add("ime_switcher_showing");
+        if ((flags & SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING) != 0) {
+            str.add("ime_switcher_button_visible");
         }
         if ((flags & SYSUI_STATE_DEVICE_DOZING) != 0) {
             str.add("device_dozing");
diff --git a/packages/SystemUI/src/com/android/systemui/navigationbar/NavBarHelper.java b/packages/SystemUI/src/com/android/systemui/navigationbar/NavBarHelper.java
index 173a964cc5d3..40197b2daf49 100644
--- a/packages/SystemUI/src/com/android/systemui/navigationbar/NavBarHelper.java
+++ b/packages/SystemUI/src/com/android/systemui/navigationbar/NavBarHelper.java
@@ -536,8 +536,10 @@ public final class NavBarHelper implements
     }
 
     /**
-     * @return Whether the IME is shown on top of the screen given the {@code vis} flag of
-     * {@link InputMethodService} and the keyguard states.
+     * Checks whether the IME is shown on top of the screen, based on the given IME window
+     * visibility flags, and the current keyguard state.
+     *
+     * @param vis the IME window visibility.
      */
     public boolean isImeShown(@ImeWindowVisibility int vis) {
         View shadeWindowView =  mNotificationShadeWindowController.getWindowRootView();
diff --git a/packages/SystemUI/src/com/android/systemui/navigationbar/TaskbarDelegate.java b/packages/SystemUI/src/com/android/systemui/navigationbar/TaskbarDelegate.java
index 2ae5b2cb4931..dfbf4d1fbaf4 100644
--- a/packages/SystemUI/src/com/android/systemui/navigationbar/TaskbarDelegate.java
+++ b/packages/SystemUI/src/com/android/systemui/navigationbar/TaskbarDelegate.java
@@ -18,7 +18,7 @@ package com.android.systemui.navigationbar;
 
 import static android.app.ActivityManager.LOCK_TASK_MODE_PINNED;
 import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SHOWN;
-import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_SHOWN;
+import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN;
 import static android.app.StatusBarManager.WINDOW_STATE_SHOWING;
 import static android.view.WindowInsetsController.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE;
 import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION;
@@ -31,12 +31,13 @@ import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_A
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_BACK_DISABLED;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_HOME_DISABLED;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_IME_SHOWING;
-import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_IME_SWITCHER_SHOWING;
+import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_NAV_BAR_HIDDEN;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_OVERVIEW_DISABLED;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_SCREEN_PINNING;
 
 import android.app.StatusBarManager;
+import android.app.StatusBarManager.NavigationHint;
 import android.app.StatusBarManager.WindowVisibleState;
 import android.content.Context;
 import android.graphics.Rect;
@@ -109,6 +110,7 @@ public class TaskbarDelegate implements CommandQueue.Callbacks,
     private TaskStackChangeListeners mTaskStackChangeListeners;
     private Optional<Pip> mPipOptional;
     private int mDefaultDisplayId;
+    @NavigationHint
     private int mNavigationIconHints;
     private final NavBarHelper.NavbarTaskbarStateUpdater mNavbarTaskbarStateUpdater =
             new NavBarHelper.NavbarTaskbarStateUpdater() {
@@ -337,8 +339,8 @@ public class TaskbarDelegate implements CommandQueue.Callbacks,
                 .setFlag(SYSUI_STATE_A11Y_BUTTON_LONG_CLICKABLE, longClickable)
                 .setFlag(SYSUI_STATE_IME_SHOWING,
                         (mNavigationIconHints & NAVIGATION_HINT_IME_SHOWN) != 0)
-                .setFlag(SYSUI_STATE_IME_SWITCHER_SHOWING,
-                        (mNavigationIconHints & NAVIGATION_HINT_IME_SWITCHER_SHOWN) != 0)
+                .setFlag(SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING,
+                        (mNavigationIconHints & NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN) != 0)
                 .setFlag(SYSUI_STATE_OVERVIEW_DISABLED,
                         (mDisabledFlags & View.STATUS_BAR_DISABLE_RECENT) != 0)
                 .setFlag(SYSUI_STATE_HOME_DISABLED,
@@ -464,12 +466,14 @@ public class TaskbarDelegate implements CommandQueue.Callbacks,
             imeShown = (vis & InputMethodService.IME_VISIBLE_IMPERCEPTIBLE) != 0;
         }
         showImeSwitcher = imeShown && showImeSwitcher;
-        int hints = Utilities.calculateBackDispositionHints(mNavigationIconHints, backDisposition,
+        int hints = Utilities.calculateNavigationIconHints(mNavigationIconHints, backDisposition,
                 imeShown, showImeSwitcher);
-        if (hints != mNavigationIconHints) {
-            mNavigationIconHints = hints;
-            updateSysuiFlags();
+        if (hints == mNavigationIconHints) {
+            return;
         }
+
+        mNavigationIconHints = hints;
+        updateSysuiFlags();
     }
 
     @Override
diff --git a/packages/SystemUI/src/com/android/systemui/navigationbar/views/NavigationBar.java b/packages/SystemUI/src/com/android/systemui/navigationbar/views/NavigationBar.java
index 6054d3ae6645..3223d02c6a0c 100644
--- a/packages/SystemUI/src/com/android/systemui/navigationbar/views/NavigationBar.java
+++ b/packages/SystemUI/src/com/android/systemui/navigationbar/views/NavigationBar.java
@@ -18,11 +18,12 @@ package com.android.systemui.navigationbar.views;
 
 import static android.app.ActivityManager.LOCK_TASK_MODE_PINNED;
 import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SHOWN;
-import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_SHOWN;
+import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN;
 import static android.app.StatusBarManager.WINDOW_STATE_HIDDEN;
 import static android.app.StatusBarManager.WINDOW_STATE_SHOWING;
 import static android.app.StatusBarManager.WindowType;
 import static android.app.StatusBarManager.WindowVisibleState;
+import static android.app.StatusBarManager.navigationHintsToString;
 import static android.app.StatusBarManager.windowStateToString;
 import static android.app.WindowConfiguration.ROTATION_UNDEFINED;
 import static android.view.InsetsSource.FLAG_SUPPRESS_SCRIM;
@@ -43,7 +44,7 @@ import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_A
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_A11Y_BUTTON_LONG_CLICKABLE;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_ALLOW_GESTURE_IGNORING_BAR_VISIBILITY;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_IME_SHOWING;
-import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_IME_SWITCHER_SHOWING;
+import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_NAV_BAR_HIDDEN;
 import static com.android.systemui.shared.system.QuickStepContract.SYSUI_STATE_SCREEN_PINNING;
 import static com.android.systemui.shared.system.QuickStepContract.isGesturalMode;
@@ -56,6 +57,7 @@ import android.annotation.NonNull;
 import android.app.ActivityTaskManager;
 import android.app.IActivityTaskManager;
 import android.app.StatusBarManager;
+import android.app.StatusBarManager.NavigationHint;
 import android.content.Context;
 import android.content.res.Configuration;
 import android.graphics.Insets;
@@ -233,6 +235,7 @@ public class NavigationBar extends ViewController<NavigationBarView> implements
 
     private @WindowVisibleState int mNavigationBarWindowState = WINDOW_STATE_SHOWING;
 
+    @NavigationHint
     private int mNavigationIconHints = 0;
     private @TransitionMode int mTransitionMode;
     private boolean mLongPressHomeEnabled;
@@ -817,7 +820,6 @@ public class NavigationBar extends ViewController<NavigationBarView> implements
         if (mSavedState != null) {
             getBarTransitions().getLightTransitionsController().restoreState(mSavedState);
         }
-        setNavigationIconHints(mNavigationIconHints);
         setWindowVisible(isNavBarWindowVisible());
         mView.setBehavior(mBehavior);
         setNavBarMode(mNavBarMode);
@@ -1111,6 +1113,7 @@ public class NavigationBar extends ViewController<NavigationBarView> implements
         pw.println("  mLongPressHomeEnabled=" + mLongPressHomeEnabled);
         pw.println("  mNavigationBarWindowState="
                 + windowStateToString(mNavigationBarWindowState));
+        pw.println("  mNavigationIconHints=" + navigationHintsToString(mNavigationIconHints));
         pw.println("  mTransitionMode="
                 + BarTransitions.modeToString(mTransitionMode));
         pw.println("  mTransientShown=" + mTransientShown);
@@ -1137,9 +1140,11 @@ public class NavigationBar extends ViewController<NavigationBarView> implements
         }
         boolean imeShown = mNavBarHelper.isImeShown(vis);
         showImeSwitcher = imeShown && showImeSwitcher;
-        int hints = Utilities.calculateBackDispositionHints(mNavigationIconHints, backDisposition,
+        int hints = Utilities.calculateNavigationIconHints(mNavigationIconHints, backDisposition,
                 imeShown, showImeSwitcher);
-        if (hints == mNavigationIconHints) return;
+        if (hints == mNavigationIconHints) {
+            return;
+        }
 
         setNavigationIconHints(hints);
         checkBarModes();
@@ -1682,8 +1687,8 @@ public class NavigationBar extends ViewController<NavigationBarView> implements
                 .setFlag(SYSUI_STATE_NAV_BAR_HIDDEN, !isNavBarWindowVisible())
                 .setFlag(SYSUI_STATE_IME_SHOWING,
                         (mNavigationIconHints & NAVIGATION_HINT_IME_SHOWN) != 0)
-                .setFlag(SYSUI_STATE_IME_SWITCHER_SHOWING,
-                        (mNavigationIconHints & NAVIGATION_HINT_IME_SWITCHER_SHOWN) != 0)
+                .setFlag(SYSUI_STATE_IME_SWITCHER_BUTTON_SHOWING,
+                        (mNavigationIconHints & NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN) != 0)
                 .setFlag(SYSUI_STATE_ALLOW_GESTURE_IGNORING_BAR_VISIBILITY,
                         allowSystemGestureIgnoringBarVisibility())
                 .commitUpdate(mDisplayId);
@@ -1927,12 +1932,20 @@ public class NavigationBar extends ViewController<NavigationBarView> implements
             };
 
     @VisibleForTesting
+    @NavigationHint
     int getNavigationIconHints() {
         return mNavigationIconHints;
     }
 
-    private void setNavigationIconHints(int hints) {
-        if (hints == mNavigationIconHints) return;
+    /**
+     * Updates the navigation icons based on {@code hints}.
+     *
+     * @param hints bit flags defined in {@link StatusBarManager}.
+     */
+    private void setNavigationIconHints(@NavigationHint int hints) {
+        if (hints == mNavigationIconHints) {
+            return;
+        }
         if (!isLargeScreen(mContext)) {
             // All IME functions handled by launcher via Sysui flags for large screen
             final boolean newBackAlt = (hints & StatusBarManager.NAVIGATION_HINT_BACK_ALT) != 0;
@@ -1946,9 +1959,8 @@ public class NavigationBar extends ViewController<NavigationBarView> implements
             mView.setNavigationIconHints(hints);
         }
         if (DEBUG) {
-            android.widget.Toast.makeText(mContext,
-                    "Navigation icon hints = " + hints,
-                    500).show();
+            android.widget.Toast.makeText(mContext, "Navigation icon hints = " + hints, 500)
+                    .show();
         }
         mNavigationIconHints = hints;
     }
diff --git a/packages/SystemUI/src/com/android/systemui/navigationbar/views/NavigationBarView.java b/packages/SystemUI/src/com/android/systemui/navigationbar/views/NavigationBarView.java
index d5ae72165c4a..ed8e538cc895 100644
--- a/packages/SystemUI/src/com/android/systemui/navigationbar/views/NavigationBarView.java
+++ b/packages/SystemUI/src/com/android/systemui/navigationbar/views/NavigationBarView.java
@@ -16,6 +16,9 @@
 
 package com.android.systemui.navigationbar.views;
 
+import static android.app.StatusBarManager.NAVIGATION_HINT_BACK_ALT;
+import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SHOWN;
+import static android.app.StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN;
 import static android.inputmethodservice.InputMethodService.canImeRenderGesturalNavButtons;
 import static android.view.WindowManagerPolicyConstants.NAV_BAR_MODE_GESTURAL;
 
@@ -31,7 +34,7 @@ import android.animation.PropertyValuesHolder;
 import android.animation.TimeInterpolator;
 import android.animation.ValueAnimator;
 import android.annotation.DrawableRes;
-import android.app.StatusBarManager;
+import android.app.StatusBarManager.NavigationHint;
 import android.content.Context;
 import android.content.res.Configuration;
 import android.graphics.Canvas;
@@ -113,6 +116,7 @@ public class NavigationBarView extends FrameLayout {
 
     boolean mLongClickableAccessibilityButton;
     int mDisabledFlags = 0;
+    @NavigationHint
     int mNavigationIconHints = 0;
     private int mNavBarMode;
     private boolean mImeDrawsImeNavBar;
@@ -499,8 +503,7 @@ public class NavigationBarView extends FrameLayout {
     }
 
     private void orientBackButton(KeyButtonDrawable drawable) {
-        final boolean useAltBack =
-                (mNavigationIconHints & StatusBarManager.NAVIGATION_HINT_BACK_ALT) != 0;
+        final boolean useAltBack = (mNavigationIconHints & NAVIGATION_HINT_BACK_ALT) != 0;
         final boolean isRtl = mConfiguration.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL;
         float degrees = useAltBack ? (isRtl ? 90 : -90) : 0;
         if (drawable.getRotation() == degrees) {
@@ -555,8 +558,10 @@ public class NavigationBarView extends FrameLayout {
         super.setLayoutDirection(layoutDirection);
     }
 
-    void setNavigationIconHints(int hints) {
-        if (hints == mNavigationIconHints) return;
+    void setNavigationIconHints(@NavigationHint int hints) {
+        if (hints == mNavigationIconHints) {
+            return;
+        }
         mNavigationIconHints = hints;
         updateNavButtonIcons();
     }
@@ -594,8 +599,7 @@ public class NavigationBarView extends FrameLayout {
         // We have to replace or restore the back and home button icons when exiting or entering
         // carmode, respectively. Recents are not available in CarMode in nav bar so change
         // to recent icon is not required.
-        final boolean useAltBack =
-                (mNavigationIconHints & StatusBarManager.NAVIGATION_HINT_BACK_ALT) != 0;
+        final boolean useAltBack = (mNavigationIconHints & NAVIGATION_HINT_BACK_ALT) != 0;
         KeyButtonDrawable backIcon = mBackIcon;
         orientBackButton(backIcon);
         KeyButtonDrawable homeIcon = mHomeDefaultIcon;
@@ -607,11 +611,12 @@ public class NavigationBarView extends FrameLayout {
 
         updateRecentsIcon();
 
-        // Update IME button visibility, a11y and rotate button always overrides the appearance
-        boolean disableImeSwitcher =
-                (mNavigationIconHints & StatusBarManager.NAVIGATION_HINT_IME_SWITCHER_SHOWN) == 0
-                || isImeRenderingNavButtons();
-        mContextualButtonGroup.setButtonVisibility(R.id.ime_switcher, !disableImeSwitcher);
+        // Update IME switcher button visibility, a11y and rotate button always overrides
+        // the appearance
+        boolean isImeSwitcherButtonVisible =
+                (mNavigationIconHints & NAVIGATION_HINT_IME_SWITCHER_BUTTON_SHOWN) != 0
+                        && !isImeRenderingNavButtons();
+        mContextualButtonGroup.setButtonVisibility(R.id.ime_switcher, isImeSwitcherButtonVisible);
 
         mBarTransitions.reapplyDarkIntensity();
 
@@ -665,7 +670,7 @@ public class NavigationBarView extends FrameLayout {
     boolean isImeRenderingNavButtons() {
         return mImeDrawsImeNavBar
                 && mImeCanRenderGesturalNavButtons
-                && (mNavigationIconHints & StatusBarManager.NAVIGATION_HINT_IME_SHOWN) != 0;
+                && (mNavigationIconHints & NAVIGATION_HINT_IME_SHOWN) != 0;
     }
 
     @VisibleForTesting
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java b/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java
index c6a4d15705f0..768696e84f89 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java
@@ -271,12 +271,12 @@ public class CommandQueue extends IStatusBar.Stub implements
         default void toggleQuickSettingsPanel() { }
 
         /**
-         * Called to notify IME window status changes.
+         * Sets the new IME window status.
          *
-         * @param displayId The id of the display to notify.
-         * @param vis IME visibility.
-         * @param backDisposition Disposition mode of back button.
-         * @param showImeSwitcher {@code true} to show IME switch button.
+         * @param displayId The id of the display to which the IME is bound.
+         * @param vis The IME window visibility.
+         * @param backDisposition The IME back disposition mode.
+         * @param showImeSwitcher Whether the IME Switcher button should be shown.
          */
         default void setImeWindowStatus(int displayId, @ImeWindowVisibility int vis,
                 @BackDispositionMode int backDisposition, boolean showImeSwitcher) { }
diff --git a/services/core/java/com/android/server/statusbar/StatusBarManagerInternal.java b/services/core/java/com/android/server/statusbar/StatusBarManagerInternal.java
index 1f162a26fa95..926472425fe2 100644
--- a/services/core/java/com/android/server/statusbar/StatusBarManagerInternal.java
+++ b/services/core/java/com/android/server/statusbar/StatusBarManagerInternal.java
@@ -54,12 +54,12 @@ public interface StatusBarManagerInternal {
     void toggleKeyboardShortcutsMenu(int deviceId);
 
     /**
-     * Used by InputMethodManagerService to notify the IME status.
+     * Sets the new IME window status.
      *
-     * @param displayId The display to which the IME is bound to.
-     * @param vis The IME visibility.
-     * @param backDisposition The IME back disposition.
-     * @param showImeSwitcher {@code true} when the IME switcher button should be shown.
+     * @param displayId The id of the display to which the IME is bound.
+     * @param vis The IME window visibility.
+     * @param backDisposition The IME back disposition mode.
+     * @param showImeSwitcher Whether the IME Switcher button should be shown.
      */
     void setImeWindowStatus(int displayId, @ImeWindowVisibility int vis,
             @BackDispositionMode int backDisposition, boolean showImeSwitcher);