diff --git a/res/values/strings.xml b/res/values/strings.xml
index 24ea35e..a906040 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -2368,6 +2368,10 @@
     <string name="location_category_recent_location_requests">Recent location requests</string>
     <!-- [CHAR LIMIT=30] Location settings screen, sub category for location services -->
     <string name="location_category_location_services">Location services</string>
+    <!-- [CHAR LIMIT=30] Location settings screen, recent location requests high battery use-->
+    <string name="location_high_battery_use">High battery use</string>
+    <!-- [CHAR LIMIT=30] Location settings screen, recent location requests low battery use-->
+    <string name="location_low_battery_use">Low battery use</string>
     <!-- [CHAR LIMIT=30] Location mode screen, screen title -->
     <string name="location_mode_screen_title">Location mode</string>
     <!-- [CHAR LIMIT=130] Location mode screen, description for high accuracy mode -->
diff --git a/src/com/android/settings/accessibility/AccessibilityUtils.java b/src/com/android/settings/accessibility/AccessibilityUtils.java
index 66a3ed2..7282bce 100644
--- a/src/com/android/settings/accessibility/AccessibilityUtils.java
+++ b/src/com/android/settings/accessibility/AccessibilityUtils.java
@@ -33,7 +33,8 @@
  */
 class AccessibilityUtils {
     /**
-     * @return the set of enabled accessibility services
+     * @return the set of enabled accessibility services. If there are not services
+     * it returned the unmodifiable {@link Collections#emptySet()}.
      */
     static Set<ComponentName> getEnabledServicesFromSettings(Context context) {
         final String enabledServicesSetting = Settings.Secure.getString(
diff --git a/src/com/android/settings/accessibility/ToggleAccessibilityServicePreferenceFragment.java b/src/com/android/settings/accessibility/ToggleAccessibilityServicePreferenceFragment.java
index 3059dcc..0c568f0 100644
--- a/src/com/android/settings/accessibility/ToggleAccessibilityServicePreferenceFragment.java
+++ b/src/com/android/settings/accessibility/ToggleAccessibilityServicePreferenceFragment.java
@@ -39,6 +39,8 @@
 import com.android.settings.R;
 import com.android.settings.accessibility.ToggleSwitch.OnBeforeCheckedChangeListener;
 
+import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
@@ -81,6 +83,10 @@
         Set<ComponentName> enabledServices = AccessibilityUtils.getEnabledServicesFromSettings(
                 getActivity());
 
+        if (enabledServices == (Set<?>) Collections.emptySet()) {
+            enabledServices = new HashSet<ComponentName>();
+        }
+
         // Determine enabled services and accessibility state.
         ComponentName toggledService = ComponentName.unflattenFromString(preferenceKey);
         boolean accessibilityEnabled = false;
diff --git a/src/com/android/settings/location/LocationSettings.java b/src/com/android/settings/location/LocationSettings.java
index 1f012e4..97907de 100644
--- a/src/com/android/settings/location/LocationSettings.java
+++ b/src/com/android/settings/location/LocationSettings.java
@@ -36,8 +36,11 @@
 public class LocationSettings extends LocationSettingsBase
         implements CompoundButton.OnCheckedChangeListener {
     private static final String TAG = LocationSettings.class.getSimpleName();
+    /** Key for preference screen "Mode" */
     private static final String KEY_LOCATION_MODE = "location_mode";
+    /** Key for preference category "Recent location requests" */
     private static final String KEY_RECENT_LOCATION_REQUESTS = "recent_location_requests";
+    /** Key for preference category "Location services" */
     private static final String KEY_LOCATION_SERVICES = "location_services";
 
     private Switch mSwitch;
@@ -100,6 +103,9 @@
 
         Activity activity = getActivity();
 
+        RecentLocationApps recentApps = new RecentLocationApps(activity);
+        recentApps.fillAppList(mRecentLocationRequests);
+
         if (activity instanceof PreferenceActivity) {
             PreferenceActivity preferenceActivity = (PreferenceActivity) activity;
             // Only show the master switch when we're not in multi-pane mode, and not being used as
diff --git a/src/com/android/settings/location/RecentLocationApps.java b/src/com/android/settings/location/RecentLocationApps.java
new file mode 100644
index 0000000..113928f
--- /dev/null
+++ b/src/com/android/settings/location/RecentLocationApps.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2013 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.settings.location;
+
+import android.app.AppOpsManager;
+import android.content.Context;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageManager;
+import android.preference.PreferenceCategory;
+import android.preference.PreferenceManager;
+import android.preference.PreferenceScreen;
+import android.util.Log;
+
+import com.android.settings.R;
+
+import java.util.List;
+
+/**
+ * Retrieves the information of applications which accessed location recently.
+ */
+public class RecentLocationApps {
+    private static final String TAG = RecentLocationApps.class.getSimpleName();
+
+    private static final int RECENT_TIME_INTERVAL_MILLIS = 15 * 60 * 1000;
+
+    private Context mContext;
+    PackageManager mPackageManager;
+
+    public RecentLocationApps(Context context) {
+        mContext = context;
+        mPackageManager = context.getPackageManager();
+    }
+
+    /**
+     * Fills a list of applications which queried location recently within
+     * specified time.
+     */
+    public void fillAppList(PreferenceCategory container) {
+        AppOpsManager aoManager =
+                (AppOpsManager) mContext.getSystemService(Context.APP_OPS_SERVICE);
+        List<AppOpsManager.PackageOps> appOps = aoManager.getPackagesForOps(
+                new int[] {
+                    AppOpsManager.OP_MONITOR_LOCATION,
+                AppOpsManager.OP_MONITOR_HIGH_POWER_LOCATION,
+                });
+        PreferenceManager preferenceManager = container.getPreferenceManager();
+        long now = System.currentTimeMillis();
+        for (AppOpsManager.PackageOps ops : appOps) {
+            processPackageOps(now, container, preferenceManager, ops);
+        }
+    }
+
+    private void processPackageOps(
+            long now,
+            PreferenceCategory container,
+            PreferenceManager preferenceManager,
+            AppOpsManager.PackageOps ops) {
+        String packageName = ops.getPackageName();
+        List<AppOpsManager.OpEntry> entries = ops.getOps();
+        boolean highBattery = false;
+        boolean normalBattery = false;
+        for (AppOpsManager.OpEntry entry : entries) {
+            // If previous location activity is older than designated interval, ignore this app.
+            if (now - entry.getTime() <= RECENT_TIME_INTERVAL_MILLIS) {
+                switch (entry.getOp()) {
+                    case AppOpsManager.OP_MONITOR_LOCATION:
+                        normalBattery = true;
+                        break;
+                    case AppOpsManager.OP_MONITOR_HIGH_POWER_LOCATION:
+                        highBattery = true;
+                        break;
+                    default:
+                        break;
+                }
+            }
+        }
+
+        if (!highBattery && !normalBattery) {
+            if (Log.isLoggable(TAG, Log.VERBOSE)) {
+                Log.v(TAG, packageName + " hadn't used location within the time interval.");
+            }
+            return;
+        }
+
+        try {
+            PreferenceScreen screen = preferenceManager.createPreferenceScreen(mContext);
+            ApplicationInfo appInfo = mPackageManager.getApplicationInfo(
+                    packageName, PackageManager.GET_META_DATA);
+            screen.setIcon(mPackageManager.getApplicationIcon(appInfo));
+            screen.setTitle(mPackageManager.getApplicationLabel(appInfo));
+            // if used both high and low battery within the time interval, show as "high
+            // battery"
+            if (highBattery) {
+                screen.setSummary(R.string.location_high_battery_use);
+            } else {
+                screen.setSummary(R.string.location_low_battery_use);
+            }
+            container.addPreference(screen);
+        } catch (PackageManager.NameNotFoundException e) {
+            // ignore the current app and move on to the next.
+        }
+    }
+}