diff --git a/packages/SystemUI/src/com/android/systemui/appops/AppOpsControllerImpl.java b/packages/SystemUI/src/com/android/systemui/appops/AppOpsControllerImpl.java
index 49bd5bd..858ed6d 100644
--- a/packages/SystemUI/src/com/android/systemui/appops/AppOpsControllerImpl.java
+++ b/packages/SystemUI/src/com/android/systemui/appops/AppOpsControllerImpl.java
@@ -62,6 +62,8 @@
     private H mBGHandler;
     private final List<AppOpsController.Callback> mCallbacks = new ArrayList<>();
     private final ArrayMap<Integer, Set<Callback>> mCallbacksByCode = new ArrayMap<>();
+    private final PermissionFlagsCache mFlagsCache;
+    private boolean mListening;
 
     @GuardedBy("mActiveItems")
     private final List<AppOpItem> mActiveItems = new ArrayList<>();
@@ -78,8 +80,14 @@
 
     @Inject
     public AppOpsControllerImpl(Context context, @Named(BG_LOOPER_NAME) Looper bgLooper) {
+        this(context, bgLooper, new PermissionFlagsCache(context));
+    }
+
+    @VisibleForTesting
+    protected AppOpsControllerImpl(Context context, Looper bgLooper, PermissionFlagsCache cache) {
         mContext = context;
         mAppOps = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);
+        mFlagsCache = cache;
         mBGHandler = new H(bgLooper);
         final int numOps = OPS.length;
         for (int i = 0; i < numOps; i++) {
@@ -94,6 +102,7 @@
 
     @VisibleForTesting
     protected void setListening(boolean listening) {
+        mListening = listening;
         if (listening) {
             mAppOps.startWatchingActive(OPS, this);
             mAppOps.startWatchingNoted(OPS, this);
@@ -225,7 +234,7 @@
         if (permission == null) {
             return false;
         }
-        int permFlags = mContext.getPackageManager().getPermissionFlags(permission,
+        int permFlags = mFlagsCache.getPermissionFlags(permission,
                 packageName, UserHandle.getUserHandleForUid(uid));
         return (permFlags & PackageManager.FLAG_PERMISSION_USER_SENSITIVE_WHEN_GRANTED) != 0;
     }
@@ -308,7 +317,7 @@
     @Override
     public void onOpActiveChanged(int code, int uid, String packageName, boolean active) {
         if (updateActives(code, uid, packageName, active)) {
-            notifySuscribers(code, uid, packageName, active);
+            mBGHandler.post(() -> notifySuscribers(code, uid, packageName, active));
         }
     }
 
@@ -319,7 +328,7 @@
         }
         if (result != AppOpsManager.MODE_ALLOWED) return;
         addNoted(code, uid, packageName);
-        notifySuscribers(code, uid, packageName, true);
+        mBGHandler.post(() -> notifySuscribers(code, uid, packageName, true));
     }
 
     private void notifySuscribers(int code, int uid, String packageName, boolean active) {
@@ -334,6 +343,7 @@
     @Override
     public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
         pw.println("AppOpsController state:");
+        pw.println("  Listening: " + mListening);
         pw.println("  Active Items:");
         for (int i = 0; i < mActiveItems.size(); i++) {
             final AppOpItem item = mActiveItems.get(i);
diff --git a/packages/SystemUI/src/com/android/systemui/appops/PermissionFlagsCache.kt b/packages/SystemUI/src/com/android/systemui/appops/PermissionFlagsCache.kt
new file mode 100644
index 0000000..f02c7af
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/appops/PermissionFlagsCache.kt
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2019 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 com.android.systemui.appops
+
+import android.content.Context
+import android.content.pm.PackageManager
+import android.os.UserHandle
+import android.util.ArrayMap
+import com.android.internal.annotations.VisibleForTesting
+
+private data class PermissionFlag(val flag: Int, val timestamp: Long)
+
+private data class PermissionFlagKey(
+    val permission: String,
+    val packageName: String,
+    val user: UserHandle
+)
+
+internal const val CACHE_EXPIRATION = 10000L
+
+/**
+ * Cache for PackageManager's PermissionFlags.
+ *
+ * Flags older than [CACHE_EXPIRATION] will be retrieved again.
+ */
+internal open class PermissionFlagsCache(context: Context) {
+    private val packageManager = context.packageManager
+    private val permissionFlagsCache = ArrayMap<PermissionFlagKey, PermissionFlag>()
+
+    /**
+     * Retrieve permission flags from cache or PackageManager. There parameters will be passed
+     * directly to [PackageManager].
+     *
+     * Calls to this method should be done from a background thread.
+     */
+    fun getPermissionFlags(permission: String, packageName: String, user: UserHandle): Int {
+        val key = PermissionFlagKey(permission, packageName, user)
+        val now = getCurrentTime()
+        val value = permissionFlagsCache.getOrPut(key) {
+            PermissionFlag(getFlags(key), now)
+        }
+        if (now - value.timestamp > CACHE_EXPIRATION) {
+            val newValue = PermissionFlag(getFlags(key), now)
+            permissionFlagsCache.put(key, newValue)
+            return newValue.flag
+        } else {
+            return value.flag
+        }
+    }
+
+    private fun getFlags(key: PermissionFlagKey) =
+            packageManager.getPermissionFlags(key.permission, key.packageName, key.user)
+
+    @VisibleForTesting
+    protected open fun getCurrentTime() = System.currentTimeMillis()
+}
\ No newline at end of file
diff --git a/packages/SystemUI/tests/src/com/android/systemui/appops/AppOpsControllerTest.java b/packages/SystemUI/tests/src/com/android/systemui/appops/AppOpsControllerTest.java
index cc31531..540ac84 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/appops/AppOpsControllerTest.java
+++ b/packages/SystemUI/tests/src/com/android/systemui/appops/AppOpsControllerTest.java
@@ -39,7 +39,6 @@
 
 import androidx.test.filters.SmallTest;
 
-import com.android.systemui.Dependency;
 import com.android.systemui.SysuiTestCase;
 
 import org.junit.Before;
@@ -65,28 +64,32 @@
     private AppOpsController.Callback mCallback;
     @Mock
     private AppOpsControllerImpl.H mMockHandler;
+    @Mock
+    private PermissionFlagsCache mFlagsCache;
 
     private AppOpsControllerImpl mController;
+    private TestableLooper mTestableLooper;
 
     @Before
     public void setUp() {
         MockitoAnnotations.initMocks(this);
+        mTestableLooper = TestableLooper.get(this);
 
         getContext().addMockSystemService(AppOpsManager.class, mAppOpsManager);
 
         // All permissions of TEST_UID and TEST_UID_OTHER are user sensitive. None of
         // TEST_UID_NON_USER_SENSITIVE are user sensitive.
         getContext().setMockPackageManager(mPackageManager);
-        when(mPackageManager.getPermissionFlags(anyString(), anyString(),
+        when(mFlagsCache.getPermissionFlags(anyString(), anyString(),
                 eq(UserHandle.getUserHandleForUid(TEST_UID)))).thenReturn(
                 PackageManager.FLAG_PERMISSION_USER_SENSITIVE_WHEN_GRANTED);
-        when(mPackageManager.getPermissionFlags(anyString(), anyString(),
+        when(mFlagsCache.getPermissionFlags(anyString(), anyString(),
                 eq(UserHandle.getUserHandleForUid(TEST_UID_OTHER)))).thenReturn(
                 PackageManager.FLAG_PERMISSION_USER_SENSITIVE_WHEN_GRANTED);
-        when(mPackageManager.getPermissionFlags(anyString(), anyString(),
+        when(mFlagsCache.getPermissionFlags(anyString(), anyString(),
                 eq(UserHandle.getUserHandleForUid(TEST_UID_NON_USER_SENSITIVE)))).thenReturn(0);
 
-        mController = new AppOpsControllerImpl(mContext, Dependency.get(Dependency.BG_LOOPER));
+        mController = new AppOpsControllerImpl(mContext, mTestableLooper.getLooper(), mFlagsCache);
     }
 
     @Test
@@ -110,6 +113,7 @@
                 AppOpsManager.OP_RECORD_AUDIO, TEST_UID, TEST_PACKAGE_NAME, true);
         mController.onOpNoted(AppOpsManager.OP_FINE_LOCATION, TEST_UID, TEST_PACKAGE_NAME,
                 AppOpsManager.MODE_ALLOWED);
+        mTestableLooper.processAllMessages();
         verify(mCallback).onActiveStateChanged(AppOpsManager.OP_RECORD_AUDIO,
                 TEST_UID, TEST_PACKAGE_NAME, true);
     }
@@ -119,6 +123,7 @@
         mController.addCallback(new int[]{AppOpsManager.OP_FINE_LOCATION}, mCallback);
         mController.onOpActiveChanged(
                 AppOpsManager.OP_RECORD_AUDIO, TEST_UID, TEST_PACKAGE_NAME, true);
+        mTestableLooper.processAllMessages();
         verify(mCallback, never()).onActiveStateChanged(
                 anyInt(), anyInt(), anyString(), anyBoolean());
     }
@@ -129,6 +134,7 @@
         mController.removeCallback(new int[]{AppOpsManager.OP_RECORD_AUDIO}, mCallback);
         mController.onOpActiveChanged(
                 AppOpsManager.OP_RECORD_AUDIO, TEST_UID, TEST_PACKAGE_NAME, true);
+        mTestableLooper.processAllMessages();
         verify(mCallback, never()).onActiveStateChanged(
                 anyInt(), anyInt(), anyString(), anyBoolean());
     }
@@ -139,6 +145,7 @@
         mController.removeCallback(new int[]{AppOpsManager.OP_CAMERA}, mCallback);
         mController.onOpActiveChanged(
                 AppOpsManager.OP_RECORD_AUDIO, TEST_UID, TEST_PACKAGE_NAME, true);
+        mTestableLooper.processAllMessages();
         verify(mCallback).onActiveStateChanged(AppOpsManager.OP_RECORD_AUDIO,
                 TEST_UID, TEST_PACKAGE_NAME, true);
     }
diff --git a/packages/SystemUI/tests/src/com/android/systemui/appops/PermissionFlagsCacheTest.kt b/packages/SystemUI/tests/src/com/android/systemui/appops/PermissionFlagsCacheTest.kt
new file mode 100644
index 0000000..dc070de
--- /dev/null
+++ b/packages/SystemUI/tests/src/com/android/systemui/appops/PermissionFlagsCacheTest.kt
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2019 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 com.android.systemui.appops
+
+import android.content.Context
+import android.content.pm.PackageManager
+import android.os.UserHandle
+import android.testing.AndroidTestingRunner
+import androidx.test.filters.SmallTest
+import com.android.systemui.SysuiTestCase
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.ArgumentMatchers.any
+import org.mockito.ArgumentMatchers.anyString
+import org.mockito.Mock
+import org.mockito.Mockito.times
+import org.mockito.Mockito.verify
+import org.mockito.MockitoAnnotations
+
+@SmallTest
+@RunWith(AndroidTestingRunner::class)
+class PermissionFlagsCacheTest : SysuiTestCase() {
+
+    companion object {
+        const val TEST_PERMISSION = "test_permission"
+        const val TEST_PACKAGE = "test_package"
+    }
+
+    @Mock
+    private lateinit var mPackageManager: PackageManager
+    @Mock
+    private lateinit var mUserHandle: UserHandle
+    private lateinit var flagsCache: TestPermissionFlagsCache
+
+    @Before
+    fun setUp() {
+        MockitoAnnotations.initMocks(this)
+        mContext.setMockPackageManager(mPackageManager)
+        flagsCache = TestPermissionFlagsCache(mContext)
+    }
+
+    @Test
+    fun testCallsPackageManager_exactlyOnce() {
+        flagsCache.getPermissionFlags(TEST_PERMISSION, TEST_PACKAGE, mUserHandle)
+        flagsCache.time = CACHE_EXPIRATION - 1
+        verify(mPackageManager).getPermissionFlags(TEST_PERMISSION, TEST_PACKAGE, mUserHandle)
+    }
+
+    @Test
+    fun testCallsPackageManager_cacheExpired() {
+        flagsCache.getPermissionFlags(TEST_PERMISSION, TEST_PACKAGE, mUserHandle)
+        flagsCache.time = CACHE_EXPIRATION + 1
+        flagsCache.getPermissionFlags(TEST_PERMISSION, TEST_PACKAGE, mUserHandle)
+        verify(mPackageManager, times(2))
+                .getPermissionFlags(TEST_PERMISSION, TEST_PACKAGE, mUserHandle)
+    }
+
+    @Test
+    fun testCallsPackageMaanger_multipleKeys() {
+        flagsCache.getPermissionFlags(TEST_PERMISSION, TEST_PACKAGE, mUserHandle)
+        flagsCache.getPermissionFlags(TEST_PERMISSION, "", mUserHandle)
+        verify(mPackageManager, times(2))
+                .getPermissionFlags(anyString(), anyString(), any())
+    }
+
+    private class TestPermissionFlagsCache(context: Context) : PermissionFlagsCache(context) {
+        var time = 0L
+
+        override fun getCurrentTime(): Long {
+            return time
+        }
+    }
+}
\ No newline at end of file