Merge changes from topic "move_contrast_api" into udc-dev

* changes:
  Move contrast API: adapt ThemeOverlayController
  Add the contrast API to UiModeManager
  Revert "Add API to get/listen to the color contrast setting"

12 files changed, 301 insertions, 219 deletions

diff --git a/core/api/current.txt b/core/api/current.txt
index 37480520529b..6f206eee3786 100644
--- a/core/api/current.txt
+++ b/core/api/current.txt
@@ -7398,12 +7398,15 @@ package android.app {
   }
 
   public class UiModeManager {
+    method public void addContrastChangeListener(@NonNull java.util.concurrent.Executor, @NonNull android.app.UiModeManager.ContrastChangeListener);
     method public void disableCarMode(int);
     method public void enableCarMode(int);
+    method @FloatRange(from=-1.0F, to=1.0f) public float getContrast();
     method public int getCurrentModeType();
     method @NonNull public java.time.LocalTime getCustomNightModeEnd();
     method @NonNull public java.time.LocalTime getCustomNightModeStart();
     method public int getNightMode();
+    method public void removeContrastChangeListener(@NonNull android.app.UiModeManager.ContrastChangeListener);
     method public void setApplicationNightMode(int);
     method public void setCustomNightModeEnd(@NonNull java.time.LocalTime);
     method public void setCustomNightModeStart(@NonNull java.time.LocalTime);
@@ -7421,6 +7424,10 @@ package android.app {
     field public static final int MODE_NIGHT_YES = 2; // 0x2
   }
 
+  public static interface UiModeManager.ContrastChangeListener {
+    method public void onContrastChanged(@FloatRange(from=-1.0F, to=1.0f) float);
+  }
+
   public final class VoiceInteractor {
     method public android.app.VoiceInteractor.Request getActiveRequest(String);
     method public android.app.VoiceInteractor.Request[] getActiveRequests();
@@ -54161,14 +54168,12 @@ package android.view.accessibility {
     method public void addAudioDescriptionRequestedChangeListener(@NonNull java.util.concurrent.Executor, @NonNull android.view.accessibility.AccessibilityManager.AudioDescriptionRequestedChangeListener);
     method public boolean addTouchExplorationStateChangeListener(@NonNull android.view.accessibility.AccessibilityManager.TouchExplorationStateChangeListener);
     method public void addTouchExplorationStateChangeListener(@NonNull android.view.accessibility.AccessibilityManager.TouchExplorationStateChangeListener, @Nullable android.os.Handler);
-    method public void addUiContrastChangeListener(@NonNull java.util.concurrent.Executor, @NonNull android.view.accessibility.AccessibilityManager.UiContrastChangeListener);
     method @ColorInt public int getAccessibilityFocusColor();
     method public int getAccessibilityFocusStrokeWidth();
     method @Deprecated public java.util.List<android.content.pm.ServiceInfo> getAccessibilityServiceList();
     method public java.util.List<android.accessibilityservice.AccessibilityServiceInfo> getEnabledAccessibilityServiceList(int);
     method public java.util.List<android.accessibilityservice.AccessibilityServiceInfo> getInstalledAccessibilityServiceList();
     method public int getRecommendedTimeoutMillis(int, int);
-    method @FloatRange(from=-1.0F, to=1.0f) public float getUiContrast();
     method public void interrupt();
     method public static boolean isAccessibilityButtonSupported();
     method public boolean isAudioDescriptionRequested();
@@ -54180,7 +54185,6 @@ package android.view.accessibility {
     method public boolean removeAccessibilityStateChangeListener(@NonNull android.view.accessibility.AccessibilityManager.AccessibilityStateChangeListener);
     method public boolean removeAudioDescriptionRequestedChangeListener(@NonNull android.view.accessibility.AccessibilityManager.AudioDescriptionRequestedChangeListener);
     method public boolean removeTouchExplorationStateChangeListener(@NonNull android.view.accessibility.AccessibilityManager.TouchExplorationStateChangeListener);
-    method public void removeUiContrastChangeListener(@NonNull android.view.accessibility.AccessibilityManager.UiContrastChangeListener);
     method public void sendAccessibilityEvent(android.view.accessibility.AccessibilityEvent);
     field public static final int FLAG_CONTENT_CONTROLS = 4; // 0x4
     field public static final int FLAG_CONTENT_ICONS = 1; // 0x1
@@ -54203,10 +54207,6 @@ package android.view.accessibility {
     method public void onTouchExplorationStateChanged(boolean);
   }
 
-  public static interface AccessibilityManager.UiContrastChangeListener {
-    method public void onUiContrastChanged(@FloatRange(from=-1.0F, to=1.0f) float);
-  }
-
   public class AccessibilityNodeInfo implements android.os.Parcelable {
     ctor public AccessibilityNodeInfo();
     ctor public AccessibilityNodeInfo(@NonNull android.view.View);
diff --git a/core/java/android/app/IUiModeManager.aidl b/core/java/android/app/IUiModeManager.aidl
index 2242224b2769..2345c27a4587 100644
--- a/core/java/android/app/IUiModeManager.aidl
+++ b/core/java/android/app/IUiModeManager.aidl
@@ -17,6 +17,7 @@
 package android.app;
 
 import android.app.IOnProjectionStateChangedListener;
+import android.app.IUiModeManagerCallback;
 
 /**
  * Interface used to control special UI modes.
@@ -24,6 +25,11 @@ import android.app.IOnProjectionStateChangedListener;
  */
 interface IUiModeManager {
     /**
+     * @hide
+     */
+    void addCallback(IUiModeManagerCallback callback);
+
+    /**
      * Enables the car mode. Only the system can do this.
      * @hide
      */
@@ -173,4 +179,9 @@ interface IUiModeManager {
     * Returns currently set projection types.
     */
     int getActiveProjectionTypes();
+
+    /**
+    * Returns the contrast for the current user
+    */
+    float getContrast();
 }
diff --git a/core/java/android/app/IUiModeManagerCallback.aidl b/core/java/android/app/IUiModeManagerCallback.aidl
new file mode 100644
index 000000000000..47c18a8bd3cb
--- /dev/null
+++ b/core/java/android/app/IUiModeManagerCallback.aidl
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.app;
+
+/**
+* Implemented by the UiModeManager client to receive information about changes from the service.
+* This is a oneway interface since the server should not block waiting for the client.
+*
+* @hide
+*/
+oneway interface IUiModeManagerCallback {
+  void notifyContrastChanged(float contrast);
+}
diff --git a/core/java/android/app/UiModeManager.java b/core/java/android/app/UiModeManager.java
index ecab37db4ba7..d90257a69281 100644
--- a/core/java/android/app/UiModeManager.java
+++ b/core/java/android/app/UiModeManager.java
@@ -17,6 +17,7 @@
 package android.app;
 
 import android.annotation.CallbackExecutor;
+import android.annotation.FloatRange;
 import android.annotation.IntDef;
 import android.annotation.IntRange;
 import android.annotation.NonNull;
@@ -34,6 +35,7 @@ import android.os.ServiceManager;
 import android.os.ServiceManager.ServiceNotFoundException;
 import android.util.ArrayMap;
 import android.util.ArraySet;
+import android.util.Log;
 import android.util.Slog;
 
 import com.android.internal.annotations.GuardedBy;
@@ -43,10 +45,13 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.ref.WeakReference;
 import java.time.LocalTime;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.Executor;
+import java.util.stream.Stream;
 
 /**
  * This class provides access to the system uimode services.  These services
@@ -72,6 +77,10 @@ import java.util.concurrent.Executor;
  */
 @SystemService(Context.UI_MODE_SERVICE)
 public class UiModeManager {
+
+    private static final String TAG = "UiModeManager";
+
+
     /**
      * A listener with a single method that is invoked whenever the packages projecting using the
      * {@link ProjectionType}s for which it is registered change.
@@ -91,7 +100,20 @@ public class UiModeManager {
                 @NonNull Set<String> packageNames);
     }
 
-    private static final String TAG = "UiModeManager";
+    /**
+     * Listener for the UI contrast. To listen for changes to
+     * the UI contrast on the device, implement this interface and
+     * register it with the system by calling {@link #addContrastChangeListener}.
+     */
+    public interface ContrastChangeListener {
+
+        /**
+         * Called when the color contrast enabled state changes.
+         *
+         * @param contrast The color contrast as in {@link #getContrast}
+         */
+        void onContrastChanged(@FloatRange(from = -1.0f, to = 1.0f) float contrast);
+    }
 
     /**
      * Broadcast sent when the device's UI has switched to car mode, either
@@ -319,6 +341,95 @@ public class UiModeManager {
             mOnProjectionStateChangedListenerResourceManager =
             new OnProjectionStateChangedListenerResourceManager();
 
+    /**
+     * Define constants and conversions between {@link ContrastLevel}s and contrast values.
+     * <p>
+     * Contrast values are floats defined in [-1, 1], as defined in {@link #getContrast}.
+     * This is the official data type for contrast;
+     * all methods from the public API return contrast values.
+     * </p>
+     * <p>
+     * {@code ContrastLevel}, on the other hand, is an internal-only enumeration of contrasts that
+     * can be set from the system ui. Each {@code ContrastLevel} has an associated contrast value.
+     * </p>
+     * <p>
+     * Currently, a user chan chose from three contrast levels:
+     * <ul>
+     *     <li>{@link #CONTRAST_LEVEL_STANDARD}, corresponding to the default contrast value 0f</li>
+     *     <li>{@link #CONTRAST_LEVEL_MEDIUM}, corresponding to the contrast value 0.5f</li>
+     *     <li>{@link #CONTRAST_LEVEL_HIGH}, corresponding to the maximum contrast value 1f</li>
+     * </ul>
+     * </p>
+     *
+     * @hide
+     */
+    public static class ContrastUtils {
+
+        private static final float CONTRAST_MIN_VALUE = -1f;
+        private static final float CONTRAST_MAX_VALUE = 1f;
+        public static final float CONTRAST_DEFAULT_VALUE = 0f;
+
+        @IntDef(flag = true, prefix = { "CONTRAST_LEVEL_" }, value = {
+                CONTRAST_LEVEL_STANDARD,
+                CONTRAST_LEVEL_MEDIUM,
+                CONTRAST_LEVEL_HIGH
+        })
+        @Retention(RetentionPolicy.SOURCE)
+        public @interface ContrastLevel {}
+
+        public static final int CONTRAST_LEVEL_STANDARD = 0;
+        public static final int CONTRAST_LEVEL_MEDIUM = 1;
+        public static final int CONTRAST_LEVEL_HIGH = 2;
+
+        private static Stream<Integer> allContrastLevels() {
+            return Stream.of(CONTRAST_LEVEL_STANDARD, CONTRAST_LEVEL_MEDIUM, CONTRAST_LEVEL_HIGH);
+        }
+
+        /**
+         * Convert a contrast value in [-1, 1] to its associated {@link ContrastLevel}
+         */
+        public static @ContrastLevel int toContrastLevel(float contrast) {
+            if (contrast < CONTRAST_MIN_VALUE || contrast > CONTRAST_MAX_VALUE) {
+                throw new IllegalArgumentException("contrast values should be in [-1, 1]");
+            }
+            return allContrastLevels().min(Comparator.comparingDouble(contrastLevel ->
+                    Math.abs(contrastLevel - 2 * contrast))).orElseThrow();
+        }
+
+        /**
+         * Convert a {@link ContrastLevel} to its associated contrast value in [-1, 1]
+         */
+        public static float fromContrastLevel(@ContrastLevel int contrastLevel) {
+            if (allContrastLevels().noneMatch(level -> level == contrastLevel)) {
+                throw new IllegalArgumentException("unrecognized contrast level: " + contrastLevel);
+            }
+            return contrastLevel / 2f;
+        }
+    }
+
+    /**
+     * Map that stores user provided {@link ContrastChangeListener} callbacks,
+     * and the executors on which these callbacks should be called.
+     */
+    private final ArrayMap<ContrastChangeListener, Executor>
+            mContrastChangeListeners = new ArrayMap<>();
+    private float mContrast;
+
+    private final IUiModeManagerCallback.Stub mCallback = new IUiModeManagerCallback.Stub() {
+        @Override
+        public void notifyContrastChanged(float contrast) {
+            final ArrayMap<ContrastChangeListener, Executor> listeners;
+            synchronized (mLock) {
+                // if value changed in the settings, update the cached value and notify listeners
+                if (Math.abs(mContrast - contrast) < 1e-10) return;
+                mContrast = contrast;
+                listeners = new ArrayMap<>(mContrastChangeListeners);
+            }
+            listeners.forEach((listener, executor) -> executor.execute(
+                    () -> listener.onContrastChanged(mContrast)));
+        }
+    };
+
     @UnsupportedAppUsage
     /*package*/ UiModeManager() throws ServiceNotFoundException {
         this(null /* context */);
@@ -328,6 +439,12 @@ public class UiModeManager {
         mService = IUiModeManager.Stub.asInterface(
                 ServiceManager.getServiceOrThrow(Context.UI_MODE_SERVICE));
         mContext = context;
+        try {
+            mService.addCallback(mCallback);
+            mContrast = mService.getContrast();
+        } catch (RemoteException e) {
+            Log.e(TAG, "Setup failed: UiModeManagerService is dead", e);
+        }
     }
 
     /**
@@ -1067,4 +1184,56 @@ public class UiModeManager {
             return mExecutorMap.get(innerListener);
         }
     }
+
+    /**
+     * Returns the color contrast for the user.
+     * <p>
+     * <strong>Note:</strong> You need to query this only if your application is
+     * doing its own rendering and does not rely on the material rendering pipeline.
+     * </p>
+     * @return The color contrast, float in [-1, 1] where
+     * <ul>
+     *     <li> &nbsp; 0 corresponds to the default contrast </li>
+     *     <li>       -1 corresponds to the minimum contrast </li>
+     *     <li> &nbsp; 1 corresponds to the maximum contrast </li>
+     * </ul>
+     *
+     *
+     *
+     */
+    @FloatRange(from = -1.0f, to = 1.0f)
+    public float getContrast() {
+        synchronized (mLock) {
+            return mContrast;
+        }
+    }
+
+    /**
+     * Registers a {@link ContrastChangeListener} for the current user.
+     *
+     * @param executor The executor on which the listener should be called back.
+     * @param listener The listener.
+     */
+    public void addContrastChangeListener(
+            @NonNull @CallbackExecutor Executor executor,
+            @NonNull ContrastChangeListener listener) {
+        Objects.requireNonNull(executor);
+        Objects.requireNonNull(listener);
+        synchronized (mLock) {
+            mContrastChangeListeners.put(listener, executor);
+        }
+    }
+
+    /**
+     * Unregisters a {@link ContrastChangeListener} for the current user.
+     * If the listener was not registered, does nothing and returns.
+     *
+     * @param listener The listener to unregister.
+     */
+    public void removeContrastChangeListener(@NonNull ContrastChangeListener listener) {
+        Objects.requireNonNull(listener);
+        synchronized (mLock) {
+            mContrastChangeListeners.remove(listener);
+        }
+    }
 }
diff --git a/core/java/android/view/accessibility/AccessibilityManager.java b/core/java/android/view/accessibility/AccessibilityManager.java
index 9504852f6e98..5ad2476930f1 100644
--- a/core/java/android/view/accessibility/AccessibilityManager.java
+++ b/core/java/android/view/accessibility/AccessibilityManager.java
@@ -25,7 +25,6 @@ import android.accessibilityservice.AccessibilityServiceInfo.FeedbackType;
 import android.accessibilityservice.AccessibilityShortcutInfo;
 import android.annotation.CallbackExecutor;
 import android.annotation.ColorInt;
-import android.annotation.FloatRange;
 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
@@ -76,7 +75,6 @@ import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.Objects;
 import java.util.concurrent.Executor;
 
 /**
@@ -140,21 +138,6 @@ public final class AccessibilityManager {
     public static final int AUTOCLICK_DELAY_DEFAULT = 600;
 
     /**
-     * The contrast is defined as a float in [-1, 1], with a default value of 0.
-     * @hide
-     */
-    public static final float CONTRAST_MIN_VALUE = -1f;
-
-    /** @hide */
-    public static final float CONTRAST_MAX_VALUE = 1f;
-
-    /** @hide */
-    public static final float CONTRAST_DEFAULT_VALUE = 0f;
-
-    /** @hide */
-    public static final float CONTRAST_NOT_SET = Float.MIN_VALUE;
-
-    /**
      * Activity action: Launch UI to manage which accessibility service or feature is assigned
      * to the navigation bar Accessibility button.
      * <p>
@@ -288,8 +271,6 @@ public final class AccessibilityManager {
     @UnsupportedAppUsage(trackingBug = 123768939L)
     boolean mIsHighTextContrastEnabled;
 
-    private float mUiContrast;
-
     boolean mIsAudioDescriptionByDefaultRequested;
 
     // accessibility tracing state
@@ -314,9 +295,6 @@ public final class AccessibilityManager {
     private final ArrayMap<HighTextContrastChangeListener, Handler>
             mHighTextContrastStateChangeListeners = new ArrayMap<>();
 
-    private final ArrayMap<UiContrastChangeListener, Executor>
-            mUiContrastChangeListeners = new ArrayMap<>();
-
     private final ArrayMap<AccessibilityServicesStateChangeListener, Executor>
             mServicesStateChangeListeners = new ArrayMap<>();
 
@@ -390,7 +368,7 @@ public final class AccessibilityManager {
          *
          * @param manager The manager that is calling back
          */
-        void onAccessibilityServicesStateChanged(@NonNull AccessibilityManager manager);
+        void onAccessibilityServicesStateChanged(@NonNull  AccessibilityManager manager);
     }
 
     /**
@@ -412,21 +390,6 @@ public final class AccessibilityManager {
     }
 
     /**
-     * Listener for the UI contrast. To listen for changes to
-     * the UI contrast on the device, implement this interface and
-     * register it with the system by calling {@link #addUiContrastChangeListener}.
-     */
-    public interface UiContrastChangeListener {
-
-        /**
-         * Called when the color contrast enabled state changes.
-         *
-         * @param uiContrast The color contrast as in {@link #getUiContrast}
-         */
-        void onUiContrastChanged(@FloatRange(from = -1.0f, to = 1.0f) float uiContrast);
-    }
-
-    /**
      * Listener for the audio description by default state. To listen for
      * changes to the audio description by default state on the device,
      * implement this interface and register it with the system by calling
@@ -540,16 +503,6 @@ public final class AccessibilityManager {
                 updateFocusAppearanceLocked(strokeWidth, color);
             }
         }
-
-        @Override
-        public void setUiContrast(float contrast) {
-            synchronized (mLock) {
-                // if value changed in the settings, update the cached value and notify listeners
-                if (Math.abs(mUiContrast - contrast) < 1e-10) return;
-                mUiContrast = contrast;
-            }
-            mHandler.obtainMessage(MyCallback.MSG_NOTIFY_CONTRAST_CHANGED).sendToTarget();
-        }
     };
 
     /**
@@ -720,7 +673,7 @@ public final class AccessibilityManager {
     /**
      * Returns if the high text contrast in the system is enabled.
      * <p>
-     * <strong>Note:</strong> You need to query this only if your application is
+     * <strong>Note:</strong> You need to query this only if you application is
      * doing its own rendering and does not rely on the platform rendering pipeline.
      * </p>
      *
@@ -740,24 +693,6 @@ public final class AccessibilityManager {
     }
 
     /**
-     * Returns the color contrast for the user.
-     * <p>
-     * <strong>Note:</strong> You need to query this only if your application is
-     * doing its own rendering and does not rely on the platform rendering pipeline.
-     * </p>
-     * @return The color contrast, float in [-1, 1] where
-     *          0 corresponds to the default contrast
-     *         -1 corresponds to the minimum contrast that the user can set
-     *          1 corresponds to the maximum contrast that the user can set
-     */
-    @FloatRange(from = -1.0f, to = 1.0f)
-    public float getUiContrast() {
-        synchronized (mLock) {
-            return mUiContrast;
-        }
-    }
-
-    /**
      * Sends an {@link AccessibilityEvent}.
      *
      * @param event The event to send.
@@ -1346,35 +1281,6 @@ public final class AccessibilityManager {
     }
 
     /**
-     * Registers a {@link UiContrastChangeListener} for the current user.
-     *
-     * @param executor The executor on which the listener should be called back.
-     * @param listener The listener.
-     */
-    public void addUiContrastChangeListener(
-            @NonNull @CallbackExecutor Executor executor,
-            @NonNull UiContrastChangeListener listener) {
-        Objects.requireNonNull(executor);
-        Objects.requireNonNull(listener);
-        synchronized (mLock) {
-            mUiContrastChangeListeners.put(listener, executor);
-        }
-    }
-
-    /**
-     * Unregisters a {@link UiContrastChangeListener} for the current user.
-     * If the listener was not registered, does nothing and returns.
-     *
-     * @param listener The listener to unregister.
-     */
-    public void removeUiContrastChangeListener(@NonNull UiContrastChangeListener listener) {
-        Objects.requireNonNull(listener);
-        synchronized (mLock) {
-            mUiContrastChangeListeners.remove(listener);
-        }
-    }
-
-    /**
      * Registers a {@link AudioDescriptionRequestedChangeListener}
      * for changes in the audio description by default state of the system.
      * The value could be read via {@link #isAudioDescriptionRequested}.
@@ -2232,7 +2138,6 @@ public final class AccessibilityManager {
             mRelevantEventTypes = IntPair.second(userStateAndRelevantEvents);
             updateUiTimeout(service.getRecommendedTimeoutMillis());
             updateFocusAppearanceLocked(service.getFocusStrokeWidth(), service.getFocusColor());
-            mUiContrast = service.getUiContrast();
             mService = service;
         } catch (RemoteException re) {
             Log.e(LOG_TAG, "AccessibilityManagerService is dead", re);
@@ -2311,22 +2216,6 @@ public final class AccessibilityManager {
     }
 
     /**
-     * Notifies the registered {@link UiContrastChangeListener}s if the value changed.
-     */
-    private void notifyUiContrastChanged() {
-        final ArrayMap<UiContrastChangeListener, Executor> listeners;
-        synchronized (mLock) {
-            listeners = new ArrayMap<>(mUiContrastChangeListeners);
-        }
-
-        listeners.entrySet().forEach(entry -> {
-            UiContrastChangeListener listener = entry.getKey();
-            Executor executor = entry.getValue();
-            executor.execute(() -> listener.onUiContrastChanged(mUiContrast));
-        });
-    }
-
-    /**
      * Notifies the registered {@link AudioDescriptionStateChangeListener}s.
      */
     private void notifyAudioDescriptionbyDefaultStateChanged() {
@@ -2416,7 +2305,6 @@ public final class AccessibilityManager {
 
     private final class MyCallback implements Handler.Callback {
         public static final int MSG_SET_STATE = 1;
-        public static final int MSG_NOTIFY_CONTRAST_CHANGED = 2;
 
         @Override
         public boolean handleMessage(Message message) {
@@ -2428,9 +2316,6 @@ public final class AccessibilityManager {
                         setStateLocked(state);
                     }
                 } break;
-                case MSG_NOTIFY_CONTRAST_CHANGED: {
-                    notifyUiContrastChanged();
-                }
             }
             return true;
         }
diff --git a/core/java/android/view/accessibility/IAccessibilityManager.aidl b/core/java/android/view/accessibility/IAccessibilityManager.aidl
index 1302421d0ce2..c8280583f35d 100644
--- a/core/java/android/view/accessibility/IAccessibilityManager.aidl
+++ b/core/java/android/view/accessibility/IAccessibilityManager.aidl
@@ -120,8 +120,6 @@ interface IAccessibilityManager {
     // Used by UiAutomation for tests on the InputFilter
     void injectInputEventToInputFilter(in InputEvent event);
 
-    float getUiContrast();
-
     boolean startFlashNotificationSequence(String opPkg, int reason, IBinder token);
     boolean stopFlashNotificationSequence(String opPkg);
     boolean startFlashNotificationEvent(String opPkg, int reason, String reasonPkg);
diff --git a/core/java/android/view/accessibility/IAccessibilityManagerClient.aidl b/core/java/android/view/accessibility/IAccessibilityManagerClient.aidl
index 931f862e581b..041399ccb8ec 100644
--- a/core/java/android/view/accessibility/IAccessibilityManagerClient.aidl
+++ b/core/java/android/view/accessibility/IAccessibilityManagerClient.aidl
@@ -31,6 +31,4 @@ oneway interface IAccessibilityManagerClient {
     void setRelevantEventTypes(int eventTypes);
 
     void setFocusAppearance(int strokeWidth, int color);
-
-    void setUiContrast(float contrast);
 }
diff --git a/packages/SystemUI/src/com/android/systemui/theme/ThemeOverlayController.java b/packages/SystemUI/src/com/android/systemui/theme/ThemeOverlayController.java
index 2ad3558fdb16..faae8df44ed9 100644
--- a/packages/SystemUI/src/com/android/systemui/theme/ThemeOverlayController.java
+++ b/packages/SystemUI/src/com/android/systemui/theme/ThemeOverlayController.java
@@ -29,6 +29,7 @@ import static com.android.systemui.theme.ThemeOverlayApplier.OVERLAY_COLOR_INDEX
 import static com.android.systemui.theme.ThemeOverlayApplier.OVERLAY_COLOR_SOURCE;
 import static com.android.systemui.theme.ThemeOverlayApplier.TIMESTAMP_FIELD;
 
+import android.app.UiModeManager;
 import android.app.WallpaperColors;
 import android.app.WallpaperManager;
 import android.app.WallpaperManager.OnColorsChangedListener;
@@ -54,7 +55,6 @@ import android.util.ArraySet;
 import android.util.Log;
 import android.util.SparseArray;
 import android.util.SparseIntArray;
-import android.view.accessibility.AccessibilityManager;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
@@ -140,8 +140,8 @@ public class ThemeOverlayController implements CoreStartable, Dumpable {
     private boolean mNeedsOverlayCreation;
     // Dominant color extracted from wallpaper, NOT the color used on the overlay
     protected int mMainWallpaperColor = Color.TRANSPARENT;
-    // UI contrast as reported by AccessibilityManager
-    private float mUiContrast = 0;
+    // UI contrast as reported by UiModeManager
+    private float mContrast = 0;
     // Theme variant: Vibrant, Tonal, Expressive, etc
     @VisibleForTesting
     protected Style mThemeStyle = Style.TONAL_SPOT;
@@ -158,7 +158,7 @@ public class ThemeOverlayController implements CoreStartable, Dumpable {
     private final SparseArray<WallpaperColors> mDeferredWallpaperColors = new SparseArray<>();
     private final SparseIntArray mDeferredWallpaperColorsFlags = new SparseIntArray();
     private final WakefulnessLifecycle mWakefulnessLifecycle;
-    private final AccessibilityManager mAccessibilityManager;
+    private final UiModeManager mUiModeManager;
     private DynamicScheme mDynamicSchemeDark;
     private DynamicScheme mDynamicSchemeLight;
 
@@ -392,7 +392,7 @@ public class ThemeOverlayController implements CoreStartable, Dumpable {
             FeatureFlags featureFlags,
             @Main Resources resources,
             WakefulnessLifecycle wakefulnessLifecycle,
-            AccessibilityManager accessibilityManager) {
+            UiModeManager uiModeManager) {
         mContext = context;
         mIsMonochromaticEnabled = featureFlags.isEnabled(Flags.MONOCHROMATIC_THEME);
         mIsMonetEnabled = featureFlags.isEnabled(Flags.MONET);
@@ -408,7 +408,7 @@ public class ThemeOverlayController implements CoreStartable, Dumpable {
         mUserTracker = userTracker;
         mResources = resources;
         mWakefulnessLifecycle = wakefulnessLifecycle;
-        mAccessibilityManager = accessibilityManager;
+        mUiModeManager = uiModeManager;
         dumpManager.registerDumpable(TAG, this);
     }
 
@@ -445,9 +445,9 @@ public class ThemeOverlayController implements CoreStartable, Dumpable {
                     }
                 },
                 UserHandle.USER_ALL);
-        mUiContrast = mAccessibilityManager.getUiContrast();
-        mAccessibilityManager.addUiContrastChangeListener(mMainExecutor, uiContrast -> {
-            mUiContrast = uiContrast;
+        mContrast = mUiModeManager.getContrast();
+        mUiModeManager.addContrastChangeListener(mMainExecutor, contrast -> {
+            mContrast = contrast;
             // Force reload so that we update even when the main color has not changed
             reevaluateSystemTheme(true /* forceReload */);
         });
@@ -586,9 +586,9 @@ public class ThemeOverlayController implements CoreStartable, Dumpable {
         mSecondaryOverlay = createAccentOverlay();
 
         mDynamicSchemeDark = dynamicSchemeFromStyle(
-                mThemeStyle, color, true /* isDark */, mUiContrast);
+                mThemeStyle, color, true /* isDark */, mContrast);
         mDynamicSchemeLight = dynamicSchemeFromStyle(
-                mThemeStyle, color, false /* isDark */, mUiContrast);
+                mThemeStyle, color, false /* isDark */, mContrast);
         mDynamicOverlay = createDynamicOverlay();
     }
 
diff --git a/packages/SystemUI/tests/src/com/android/systemui/theme/ThemeOverlayControllerTest.java b/packages/SystemUI/tests/src/com/android/systemui/theme/ThemeOverlayControllerTest.java
index f9b5767bf53c..17b5e0546eca 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/theme/ThemeOverlayControllerTest.java
+++ b/packages/SystemUI/tests/src/com/android/systemui/theme/ThemeOverlayControllerTest.java
@@ -33,6 +33,7 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.when;
 
+import android.app.UiModeManager;
 import android.app.WallpaperColors;
 import android.app.WallpaperManager;
 import android.content.BroadcastReceiver;
@@ -47,7 +48,6 @@ import android.os.UserHandle;
 import android.os.UserManager;
 import android.provider.Settings;
 import android.testing.AndroidTestingRunner;
-import android.view.accessibility.AccessibilityManager;
 
 import androidx.annotation.VisibleForTesting;
 import androidx.test.filters.SmallTest;
@@ -116,7 +116,7 @@ public class ThemeOverlayControllerTest extends SysuiTestCase {
     @Mock
     private WakefulnessLifecycle mWakefulnessLifecycle;
     @Mock
-    private AccessibilityManager mAccessibilityManager;
+    private UiModeManager mUiModeManager;
     @Captor
     private ArgumentCaptor<BroadcastReceiver> mBroadcastReceiver;
     @Captor
@@ -135,7 +135,7 @@ public class ThemeOverlayControllerTest extends SysuiTestCase {
         MockitoAnnotations.initMocks(this);
         when(mFeatureFlags.isEnabled(Flags.MONET)).thenReturn(true);
         when(mWakefulnessLifecycle.getWakefulness()).thenReturn(WAKEFULNESS_AWAKE);
-        when(mAccessibilityManager.getUiContrast()).thenReturn(0.5f);
+        when(mUiModeManager.getContrast()).thenReturn(0.5f);
         when(mDeviceProvisionedController.isCurrentUserSetup()).thenReturn(true);
         when(mResources.getColor(eq(android.R.color.system_accent1_500), any()))
                 .thenReturn(Color.RED);
@@ -151,7 +151,7 @@ public class ThemeOverlayControllerTest extends SysuiTestCase {
                 mBroadcastDispatcher, mBgHandler, mMainExecutor, mBgExecutor, mThemeOverlayApplier,
                 mSecureSettings, mWallpaperManager, mUserManager, mDeviceProvisionedController,
                 mUserTracker, mDumpManager, mFeatureFlags, mResources, mWakefulnessLifecycle,
-                mAccessibilityManager) {
+                mUiModeManager) {
             @VisibleForTesting
             protected boolean isNightMode() {
                 return false;
@@ -733,7 +733,7 @@ public class ThemeOverlayControllerTest extends SysuiTestCase {
                 mBroadcastDispatcher, mBgHandler, executor, executor, mThemeOverlayApplier,
                 mSecureSettings, mWallpaperManager, mUserManager, mDeviceProvisionedController,
                 mUserTracker, mDumpManager, mFeatureFlags, mResources, mWakefulnessLifecycle,
-                mAccessibilityManager) {
+                mUiModeManager) {
             @VisibleForTesting
             protected boolean isNightMode() {
                 return false;
@@ -773,7 +773,7 @@ public class ThemeOverlayControllerTest extends SysuiTestCase {
                 mBroadcastDispatcher, mBgHandler, executor, executor, mThemeOverlayApplier,
                 mSecureSettings, mWallpaperManager, mUserManager, mDeviceProvisionedController,
                 mUserTracker, mDumpManager, mFeatureFlags, mResources, mWakefulnessLifecycle,
-                mAccessibilityManager) {
+                mUiModeManager) {
             @VisibleForTesting
             protected boolean isNightMode() {
                 return false;
diff --git a/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java b/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
index 7fba72b74e8d..6503595f2f62 100644
--- a/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
+++ b/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
@@ -26,11 +26,8 @@ import static android.accessibilityservice.AccessibilityTrace.FLAGS_USER_BROADCA
 import static android.accessibilityservice.AccessibilityTrace.FLAGS_WINDOW_MAGNIFICATION_CONNECTION;
 import static android.accessibilityservice.AccessibilityTrace.FLAGS_WINDOW_MANAGER_INTERNAL;
 import static android.provider.Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_NAVBAR_ENABLED;
-import static android.provider.Settings.Secure.CONTRAST_LEVEL;
 import static android.view.accessibility.AccessibilityManager.ACCESSIBILITY_BUTTON;
 import static android.view.accessibility.AccessibilityManager.ACCESSIBILITY_SHORTCUT_KEY;
-import static android.view.accessibility.AccessibilityManager.CONTRAST_DEFAULT_VALUE;
-import static android.view.accessibility.AccessibilityManager.CONTRAST_NOT_SET;
 import static android.view.accessibility.AccessibilityManager.FlashNotificationReason;
 import static android.view.accessibility.AccessibilityManager.ShortcutType;
 
@@ -1997,16 +1994,6 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
         return false;
     }
 
-    private boolean readUiContrastLocked(AccessibilityUserState userState) {
-        float contrast = Settings.Secure.getFloatForUser(mContext.getContentResolver(),
-                CONTRAST_LEVEL, CONTRAST_DEFAULT_VALUE, userState.mUserId);
-        if (Math.abs(userState.getUiContrastLocked() - contrast) >= 1e-10) {
-            userState.setUiContrastLocked(contrast);
-            return true;
-        }
-        return false;
-    }
-
     /**
      * Performs {@link AccessibilityService}s delayed notification. The delay is configurable
      * and denotes the period after the last event before notifying the service.
@@ -2676,7 +2663,6 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
         somethingChanged |= readMagnificationCapabilitiesLocked(userState);
         somethingChanged |= readMagnificationFollowTypingLocked(userState);
         somethingChanged |= readAlwaysOnMagnificationLocked(userState);
-        somethingChanged |= readUiContrastLocked(userState);
         return somethingChanged;
     }
 
@@ -3851,19 +3837,6 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
         return mProxyManager.isProxyed(displayId);
     }
 
-    @Override public float getUiContrast() {
-        if (mTraceManager.isA11yTracingEnabledForTypes(FLAGS_ACCESSIBILITY_MANAGER)) {
-            mTraceManager.logTrace(LOG_TAG + ".getUiContrast", FLAGS_ACCESSIBILITY_MANAGER);
-        }
-        synchronized (mLock) {
-            AccessibilityUserState userState = getCurrentUserStateLocked();
-            float contrast = userState.getUiContrastLocked();
-            if (contrast != CONTRAST_NOT_SET) return contrast;
-            readUiContrastLocked(userState);
-            return userState.getUiContrastLocked();
-        }
-    }
-
     @Override
     public boolean startFlashNotificationSequence(String opPkg,
             @FlashNotificationReason int reason, IBinder token) {
@@ -4350,9 +4323,6 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
         private final Uri mAlwaysOnMagnificationUri = Settings.Secure.getUriFor(
                 Settings.Secure.ACCESSIBILITY_MAGNIFICATION_ALWAYS_ON_ENABLED);
 
-        private final Uri mUiContrastUri = Settings.Secure.getUriFor(
-                CONTRAST_LEVEL);
-
         public AccessibilityContentObserver(Handler handler) {
             super(handler);
         }
@@ -4395,8 +4365,6 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
                     mMagnificationFollowTypingUri, false, this, UserHandle.USER_ALL);
             contentResolver.registerContentObserver(
                     mAlwaysOnMagnificationUri, false, this, UserHandle.USER_ALL);
-            contentResolver.registerContentObserver(
-                    mUiContrastUri, false, this, UserHandle.USER_ALL);
         }
 
         @Override
@@ -4468,10 +4436,6 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
                     readMagnificationFollowTypingLocked(userState);
                 } else if (mAlwaysOnMagnificationUri.equals(uri)) {
                     readAlwaysOnMagnificationLocked(userState);
-                } else if (mUiContrastUri.equals(uri)) {
-                    if (readUiContrastLocked(userState)) {
-                        updateUiContrastLocked(userState);
-                    }
                 }
             }
         }
@@ -4788,22 +4752,7 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
                         userState.getFocusColorLocked());
             }));
         });
-    }
 
-    private void updateUiContrastLocked(AccessibilityUserState userState) {
-        if (userState.mUserId != mCurrentUserId) {
-            return;
-        }
-        if (mTraceManager.isA11yTracingEnabledForTypes(FLAGS_ACCESSIBILITY_SERVICE_CLIENT)) {
-            mTraceManager.logTrace(LOG_TAG + ".updateUiContrastLocked",
-                    FLAGS_ACCESSIBILITY_SERVICE_CLIENT, "userState=" + userState);
-        }
-        float contrast = userState.getUiContrastLocked();
-        mMainHandler.post(() -> {
-            broadcastToClients(userState, ignoreRemoteException(client -> {
-                client.mCallback.setUiContrast(contrast);
-            }));
-        });
     }
 
     public AccessibilityTraceManager getTraceManager() {
diff --git a/services/accessibility/java/com/android/server/accessibility/AccessibilityUserState.java b/services/accessibility/java/com/android/server/accessibility/AccessibilityUserState.java
index 1c9ce3c82735..3b169f8f715e 100644
--- a/services/accessibility/java/com/android/server/accessibility/AccessibilityUserState.java
+++ b/services/accessibility/java/com/android/server/accessibility/AccessibilityUserState.java
@@ -26,8 +26,6 @@ import static android.provider.Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_
 import static android.provider.Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_NONE;
 import static android.view.accessibility.AccessibilityManager.ACCESSIBILITY_BUTTON;
 import static android.view.accessibility.AccessibilityManager.ACCESSIBILITY_SHORTCUT_KEY;
-import static android.view.accessibility.AccessibilityManager.CONTRAST_DEFAULT_VALUE;
-import static android.view.accessibility.AccessibilityManager.CONTRAST_NOT_SET;
 import static android.view.accessibility.AccessibilityManager.ShortcutType;
 
 import static com.android.internal.accessibility.AccessibilityShortcutController.MAGNIFICATION_CONTROLLER_NAME;
@@ -147,8 +145,6 @@ class AccessibilityUserState {
     private final int mFocusStrokeWidthDefaultValue;
     // The default value of the focus color.
     private final int mFocusColorDefaultValue;
-    /** The color contrast in [-1, 1] */
-    private float mUiContrast = CONTRAST_DEFAULT_VALUE;
 
     private Context mContext;
 
@@ -224,7 +220,6 @@ class AccessibilityUserState {
         mFocusColor = mFocusColorDefaultValue;
         mMagnificationFollowTypingEnabled = true;
         mAlwaysOnMagnificationEnabled = false;
-        mUiContrast = CONTRAST_NOT_SET;
     }
 
     void addServiceLocked(AccessibilityServiceConnection serviceConnection) {
@@ -1001,7 +996,6 @@ class AccessibilityUserState {
         return mFocusColor;
     }
 
-
     /**
      * Sets the stroke width and color of the focus rectangle.
      *
@@ -1027,20 +1021,4 @@ class AccessibilityUserState {
         }
         return false;
     }
-
-    /**
-     * Get the color contrast
-     * @return color contrast in [-1, 1]
-     */
-    public float getUiContrastLocked() {
-        return mUiContrast;
-    }
-
-    /**
-     * Set the color contrast
-     * @param contrast the new color contrast in [-1, 1]
-     */
-    public void setUiContrastLocked(float contrast) {
-        mUiContrast = contrast;
-    }
 }
diff --git a/services/core/java/com/android/server/UiModeManagerService.java b/services/core/java/com/android/server/UiModeManagerService.java
index 5d46de335781..7c32627dd1b1 100644
--- a/services/core/java/com/android/server/UiModeManagerService.java
+++ b/services/core/java/com/android/server/UiModeManagerService.java
@@ -16,6 +16,7 @@
 
 package com.android.server;
 
+import static android.app.UiModeManager.ContrastUtils.CONTRAST_DEFAULT_VALUE;
 import static android.app.UiModeManager.DEFAULT_PRIORITY;
 import static android.app.UiModeManager.MODE_NIGHT_AUTO;
 import static android.app.UiModeManager.MODE_NIGHT_CUSTOM;
@@ -27,8 +28,11 @@ import static android.app.UiModeManager.MODE_NIGHT_YES;
 import static android.app.UiModeManager.PROJECTION_TYPE_AUTOMOTIVE;
 import static android.app.UiModeManager.PROJECTION_TYPE_NONE;
 import static android.os.UserHandle.USER_SYSTEM;
+import static android.provider.Settings.Secure.CONTRAST_LEVEL;
 import static android.util.TimeUtils.isTimeBetween;
 
+import static com.android.internal.util.FunctionalUtils.ignoreRemoteException;
+
 import android.annotation.IntRange;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
@@ -38,6 +42,7 @@ import android.app.ActivityTaskManager;
 import android.app.AlarmManager;
 import android.app.IOnProjectionStateChangedListener;
 import android.app.IUiModeManager;
+import android.app.IUiModeManagerCallback;
 import android.app.KeyguardManager;
 import android.app.Notification;
 import android.app.NotificationManager;
@@ -71,6 +76,7 @@ import android.os.ShellCallback;
 import android.os.ShellCommand;
 import android.os.SystemProperties;
 import android.os.UserHandle;
+import android.provider.Settings;
 import android.provider.Settings.Secure;
 import android.service.dreams.Sandman;
 import android.service.vr.IVrManager;
@@ -193,12 +199,19 @@ final class UiModeManagerService extends SystemService {
     private PowerManagerInternal mLocalPowerManager;
 
     @GuardedBy("mLock")
+    private final RemoteCallbackList<IUiModeManagerCallback> mUiModeManagerCallbacks =
+            new RemoteCallbackList<IUiModeManagerCallback>();
+
+    @GuardedBy("mLock")
     @Nullable
     private SparseArray<List<ProjectionHolder>> mProjectionHolders;
     @GuardedBy("mLock")
     @Nullable
     private SparseArray<RemoteCallbackList<IOnProjectionStateChangedListener>> mProjectionListeners;
 
+    @GuardedBy("mLock")
+    private final SparseArray<Float> mContrasts = new SparseArray<>();
+
     public UiModeManagerService(Context context) {
         this(context, /* setupWizardComplete= */ false, /* tm= */ null, new Injector());
     }
@@ -352,6 +365,19 @@ final class UiModeManagerService extends SystemService {
         }
     };
 
+    private final ContentObserver mContrastObserver = new ContentObserver(mHandler) {
+        @Override
+        public void onChange(boolean selfChange, Uri uri) {
+            synchronized (mLock) {
+                if (updateContrastLocked()) {
+                    float contrast = getContrastLocked();
+                    mUiModeManagerCallbacks.broadcast(ignoreRemoteException(callback ->
+                            callback.notifyContrastChanged(contrast)));
+                }
+            }
+        }
+    };
+
     private void updateSystemProperties() {
         int mode = Secure.getIntForUser(getContext().getContentResolver(), Secure.UI_NIGHT_MODE,
                 mNightMode, 0);
@@ -407,6 +433,9 @@ final class UiModeManagerService extends SystemService {
                 context.getContentResolver()
                         .registerContentObserver(Secure.getUriFor(Secure.UI_NIGHT_MODE),
                                 false, mDarkThemeObserver, 0);
+                context.getContentResolver().registerContentObserver(
+                        Secure.getUriFor(Secure.CONTRAST_LEVEL), false,
+                        mContrastObserver, UserHandle.USER_ALL);
                 context.registerReceiver(mDockModeReceiver,
                         new IntentFilter(Intent.ACTION_DOCK_EVENT));
                 IntentFilter batteryFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
@@ -634,6 +663,13 @@ final class UiModeManagerService extends SystemService {
 
     private final IUiModeManager.Stub mService = new IUiModeManager.Stub() {
         @Override
+        public void addCallback(IUiModeManagerCallback callback) {
+            synchronized (mLock) {
+                mUiModeManagerCallbacks.register(callback);
+            }
+        }
+
+        @Override
         public void enableCarMode(@UiModeManager.EnableCarMode int flags,
                 @IntRange(from = 0) int priority, String callingPackage) {
             if (isUiModeLocked()) {
@@ -1132,6 +1168,13 @@ final class UiModeManagerService extends SystemService {
                 }
             }
         }
+
+        @Override
+        public float getContrast() {
+            synchronized (mLock) {
+                return getContrastLocked();
+            }
+        }
     };
 
     private void enforceProjectionTypePermissions(@UiModeManager.ProjectionType int p) {
@@ -1214,6 +1257,30 @@ final class UiModeManagerService extends SystemService {
         }
     }
 
+    /**
+     * Return the contrast for the current user. If not cached, fetch it from the settings.
+     */
+    @GuardedBy("mLock")
+    private float getContrastLocked() {
+        if (!mContrasts.contains(mCurrentUser)) updateContrastLocked();
+        return mContrasts.get(mCurrentUser);
+    }
+
+    /**
+     * Read the contrast setting for the current user and update {@link #mContrasts}
+     * if the contrast changed. Returns true if {@link #mContrasts} was updated.
+     */
+    @GuardedBy("mLock")
+    private boolean updateContrastLocked() {
+        float contrast = Settings.Secure.getFloatForUser(getContext().getContentResolver(),
+                CONTRAST_LEVEL, CONTRAST_DEFAULT_VALUE, mCurrentUser);
+        if (Math.abs(mContrasts.get(mCurrentUser, Float.MAX_VALUE) - contrast) >= 1e-10) {
+            mContrasts.put(mCurrentUser, contrast);
+            return true;
+        }
+        return false;
+    }
+
     private static class ProjectionHolder implements IBinder.DeathRecipient {
         private final String mPackageName;
         private final @UiModeManager.ProjectionType int mProjectionType;