car-lib/src/android/car/user/CarUserManagerHelper.java - platform/packages/services/Car - Git at Google

 /*
  * Copyright (C) 2018 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.car.user;

 import android.annotation.Nullable;
 import android.app.ActivityManager;
 import android.car.settings.CarSettings;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.pm.UserInfo;
 import android.graphics.Bitmap;
 import android.graphics.drawable.BitmapDrawable;
 import android.graphics.drawable.Drawable;
 import android.os.SystemProperties;
 import android.os.UserHandle;
 import android.os.UserManager;
 import android.util.Log;

 import com.android.internal.util.UserIcons;

 import java.util.Iterator;
 import java.util.List;

 /**
  * Helper class for {@link UserManager}, this is meant to be used by builds that support
  * Multi-user model with headless user 0. User 0 is not associated with a real person, and
  * can not be brought to foreground.
  *
  * <p>This class provides method for user management, including creating, removing, adding
  * and switching users. Methods related to get users will exclude system user by default.
  *
  * @hide
  */
 public class CarUserManagerHelper {
     private static final String TAG = "CarUserManagerHelper";
     private static final String HEADLESS_SYSTEM_USER = "android.car.systemuser.headless";
     private final Context mContext;
     private final UserManager mUserManager;
     private final ActivityManager mActivityManager;
     private Bitmap mDefaultGuestUserIcon;
     private OnUsersUpdateListener mUpdateListener;
     private final BroadcastReceiver mUserChangeReceiver = new BroadcastReceiver() {
         @Override
         public void onReceive(Context context, Intent intent) {
             mUpdateListener.onUsersUpdate();
         }
     };

     public CarUserManagerHelper(Context context) {
         mContext = context.getApplicationContext();
         mUserManager = (UserManager) mContext.getSystemService(Context.USER_SERVICE);
         mActivityManager = (ActivityManager) mContext.getSystemService(Context.ACTIVITY_SERVICE);
     }

     /**
      * Registers a listener for updates to all users - removing, adding users or changing user info.
      *
      * <p> Best practise is to keep one listener per helper.
      *
      * @param listener Instance of {@link OnUsersUpdateListener}.
      */
     public void registerOnUsersUpdateListener(OnUsersUpdateListener listener) {
         if (mUpdateListener != null) {
             unregisterOnUsersUpdateListener();
         }

         mUpdateListener = listener;
         registerReceiver();
     }

     /**
      * Unregisters on user update listener by unregistering {@code BroadcastReceiver}.
      */
     public void unregisterOnUsersUpdateListener() {
         unregisterReceiver();
     }

     /**
      * Returns {@code true} if the system is in the headless user 0 model.
      *
      * @return {@boolean true} if headless system user.
      */
     public boolean isHeadlessSystemUser() {
         return SystemProperties.getBoolean(HEADLESS_SYSTEM_USER, false);
     }

     /**
      * Gets UserInfo for the system user.
      *
      * @return {@link UserInfo} for the system user.
      */
     public UserInfo getSystemUserInfo() {
         return mUserManager.getUserInfo(UserHandle.USER_SYSTEM);
     }

     /**
      * Gets UserInfo for the current foreground user.
      *
      * Concept of foreground user is relevant for the multi-user deployment. Foreground user
      * corresponds to the currently "logged in" user.
      *
      * @return {@link UserInfo} for the foreground user.
      */
     public UserInfo getCurrentForegroundUserInfo() {
         return mUserManager.getUserInfo(getCurrentForegroundUserId());
     }

     /**
      * @return Id of the current foreground user.
      */
     public int getCurrentForegroundUserId() {
         return mActivityManager.getCurrentUser();
     }

     /**
      * Gets UserInfo for the user running the caller process.
      *
      * <p>Differentiation between foreground user and current process user is relevant for
      * multi-user deployments.
      *
      * <p>Some multi-user aware components (like SystemUI) needs to run a singleton component
      * in system user. Current process user is always the same for that component, even when
      * the foreground user changes.
      *
      * @return {@link UserInfo} for the user running the current process.
      */
     public UserInfo getCurrentProcessUserInfo() {
         return mUserManager.getUserInfo(getCurrentProcessUserId());
     }

     /**
      * @return Id for the user running the current process.
      */
     public int getCurrentProcessUserId() {
         return UserHandle.myUserId();
     }

     /**
      * Gets all the existing foreground users on the system that are not currently running as
      * the foreground user.
      *
      * @return List of {@code UserInfo} for each user that is not the foreground user.
      */
     public List<UserInfo> getAllSwitchableUsers() {
         if (isHeadlessSystemUser()) {
             return getAllUsersExceptSystemUserAndSpecifiedUser(getCurrentForegroundUserId());
         } else {
             return getAllUsersExceptSpecifiedUser(getCurrentForegroundUserId());
         }
     }

     /**
      * Gets all the users that can be brought to the foreground on the system.
      *
      * @return List of {@code UserInfo} for users that associated with a real person.
      */
     public List<UserInfo> getAllUsers() {
         if (isHeadlessSystemUser()) {
             return getAllUsersExceptSystemUserAndSpecifiedUser(UserHandle.USER_SYSTEM);
         } else {
             return mUserManager.getUsers(/* excludeDying= */true);
         }
     }

     /**
      * Get all the users except the one with userId passed in.
      *
      * @param userId of the user not to be returned.
      * @return All users other than user with userId.
      */
     private List<UserInfo> getAllUsersExceptSpecifiedUser(int userId) {
         List<UserInfo> users = mUserManager.getUsers(/* excludeDying= */true);

         for (Iterator<UserInfo> iterator = users.iterator(); iterator.hasNext(); ) {
             UserInfo userInfo = iterator.next();
             if (userInfo.id == userId) {
                 // Remove user with userId from the list.
                 iterator.remove();
             }
         }
         return users;
     }

     /**
      * Get all the users except system user and the one with userId passed in.
      *
      * @param userId of the user not to be returned.
      * @return All users other than system user and user with userId.
      */
     private List<UserInfo> getAllUsersExceptSystemUserAndSpecifiedUser(int userId) {
         List<UserInfo> users = mUserManager.getUsers(/* excludeDying= */true);

         for (Iterator<UserInfo> iterator = users.iterator(); iterator.hasNext(); ) {
             UserInfo userInfo = iterator.next();
             if (userInfo.id == userId || userInfo.id == UserHandle.USER_SYSTEM) {
                 // Remove user with userId from the list.
                 iterator.remove();
             }
         }
         return users;
     }

     // User information accessors

     /**
      * Checks whether the user is system user.
      *
      * @param userInfo User to check against system user.
      * @return {@code true} if system user, {@code false} otherwise.
      */
     public boolean isSystemUser(UserInfo userInfo) {
         return userInfo.id == UserHandle.USER_SYSTEM;
     }

     /**
      * Checks whether the user is default user.
      *
      * @param userInfo User to check against system user.
      * @return {@code true} if is default user, {@code false} otherwise.
      */
     public boolean isDefaultUser(UserInfo userInfo) {
         return userInfo.id == CarSettings.DEFAULT_USER_ID_TO_BOOT_INTO;
     }

     /**
      * Checks whether passed in user is the foreground user.
      *
      * @param userInfo User to check.
      * @return {@code true} if foreground user, {@code false} otherwise.
      */
     public boolean isForegroundUser(UserInfo userInfo) {
         return getCurrentForegroundUserId() == userInfo.id;
     }

     /**
      * Checks whether passed in user is the user that's running the current process.
      *
      * @param userInfo User to check.
      * @return {@code true} if user running the process, {@code false} otherwise.
      */
     public boolean isCurrentProcessUser(UserInfo userInfo) {
         return getCurrentProcessUserId() == userInfo.id;
     }

     // Foreground user information accessors.

     /**
      * Checks if the foreground user is a guest user.
      */
     public boolean isForegroundUserGuest() {
         return getCurrentForegroundUserInfo().isGuest();
     }

     /**
      * Returns whether this user can be removed from the system.
      *
      * @param userInfo User to be removed
      * @return {@code true} if they can be removed, {@code false} otherwise.
      */
     public boolean canUserBeRemoved(UserInfo userInfo) {
         return !isSystemUser(userInfo);
     }

     /**
      * Return whether the foreground user has a restriction.
      *
      * @param restriction Restriction to check. Should be a UserManager.* restriction.
      * @return Whether that restriction exists for the foreground user.
      */
     public boolean foregroundUserHasUserRestriction(String restriction) {
         return mUserManager.hasUserRestriction(
             restriction, getCurrentForegroundUserInfo().getUserHandle());
     }

     /**
      * Checks if the foreground user can add new users.
      */
     public boolean canForegroundUserAddUsers() {
         return !foregroundUserHasUserRestriction(UserManager.DISALLOW_ADD_USER);
     }

     // Current process user information accessors

     /**
      * Checks whether this process is running under the system user.
      */
     public boolean isCurrentProcessSystemUser() {
         return mUserManager.isSystemUser();
     }

     /**
      * Checks if the calling app is running in a demo user.
      */
     public boolean isCurrentProcessDemoUser() {
         return mUserManager.isDemoUser();
     }

     /**
      * Checks if the calling app is running as a guest user.
      */
     public boolean isCurrentProcessGuestUser() {
         return mUserManager.isGuestUser();
     }

     /**
      * Check is the calling app is running as a restricted profile user (ie. a LinkedUser).
      * Restricted profiles are only available when {@link #isHeadlessSystemUser()} is false.
      */
     public boolean isCurrentProcessRestrictedProfileUser() {
         return mUserManager.isRestrictedProfile();
     }

     // Current process user restriction accessors

     /**
      * Return whether the user running the current process has a restriction.
      *
      * @param restriction Restriction to check. Should be a UserManager.* restriction.
      * @return Whether that restriction exists for the user running the process.
      */
     public boolean isCurrentProcessUserHasRestriction(String restriction) {
         return mUserManager.hasUserRestriction(restriction);
     }

     /**
      * Checks if the current process user can modify accounts. Demo and Guest users cannot modify
      * accounts even if the DISALLOW_MODIFY_ACCOUNTS restriction is not applied.
      */
     public boolean canCurrentProcessModifyAccounts() {
         return !isCurrentProcessUserHasRestriction(UserManager.DISALLOW_MODIFY_ACCOUNTS)
             && !isCurrentProcessDemoUser()
             && !isCurrentProcessGuestUser();
     }

     /**
      * Checks if the user running the current process can add new users.
      */
     public boolean canCurrentProcessAddUsers() {
         return !isCurrentProcessUserHasRestriction(UserManager.DISALLOW_ADD_USER);
     }

     /**
      * Checks if the user running the current process can remove users.
      */
     public boolean canCurrentProcessRemoveUsers() {
         return !isCurrentProcessUserHasRestriction(UserManager.DISALLOW_REMOVE_USER);
     }

     /**
      * Checks if the user running the current process is allowed to switch to another user.
      */
     public boolean canCurrentProcessSwitchUsers() {
         return !isCurrentProcessUserHasRestriction(UserManager.DISALLOW_USER_SWITCH);
     }

     /**
      * Creates a new user on the system, the created user would be granted admin role.
      *
      * @param userName Name to give to the newly created user.
      * @return Newly created admin user, null if failed to create a user.
      */
     @Nullable
     public UserInfo createNewAdminUser(String userName) {
         UserInfo user = mUserManager.createUser(userName, UserInfo.FLAG_ADMIN);
         if (user == null) {
             // Couldn't create user, most likely because there are too many, but we haven't
             // been able to reload the list yet.
             Log.w(TAG, "can't create admin user.");
             return null;
         }
         assignDefaultIcon(user);
         return user;
     }

     /**
      * Creates a new restricted user on the system.
      *
      * @param userName Name to give to the newly created user.
      * @return Newly created restricted user, null if failed to create a user.
      */
     @Nullable
     public UserInfo createNewNonAdminUser(String userName) {
         UserInfo user = mUserManager.createUser(userName, 0);
         if (user == null) {
             // Couldn't create user, most likely because there are too many, but we haven't
             // been able to reload the list yet.
             Log.w(TAG, "can't create non-admin user.");
             return null;
         }
         assignDefaultIcon(user);
         return user;
     }

     /**
      * Tries to remove the user that's passed in. System user cannot be removed.
      * If the user to be removed is user currently running the process,
      * it switches to the guest user first, and then removes the user.
      *
      * @param userInfo User to be removed
      * @return {@code true} if user is successfully removed, {@code false} otherwise.
      */
     public boolean removeUser(UserInfo userInfo, String guestUserName) {
         if (isSystemUser(userInfo)) {
             Log.w(TAG, "User " + userInfo.id + " is system user, could not be removed.");
             return false;
         }

         // Not allow to delete the default user for now. Since default user is the one to
         // boot into.
         if (isHeadlessSystemUser() && isDefaultUser(userInfo)) {
             Log.w(TAG, "User " + userInfo.id + " is the default user, could not be removed.");
             return false;
         }

         if (userInfo.id == getCurrentForegroundUserId()) {
             startNewGuestSession(guestUserName);
         }

         return mUserManager.removeUser(userInfo.id);
     }

     /**
      * Switches (logs in) to another user given user id.
      *
      * @param id User id to switch to.
      * @return {@code true} if user switching succeed.
      */
     public boolean switchToUserId(int id) {
         if (id == UserHandle.USER_SYSTEM && isHeadlessSystemUser()) {
             // System User doesn't associate with real person, can not be switched to.
             return false;
         }
         return mActivityManager.switchUser(id);
     }

     /**
      * Switches (logs in) to another user.
      *
      * @param userInfo User to switch to.
      * @return {@code true} if user switching succeed.
      */
     public boolean switchToUser(UserInfo userInfo) {
         if (userInfo.id == getCurrentForegroundUserId()) {
             return false;
         }

         return switchToUserId(userInfo.id);
     }

     /**
      * Creates a new guest session and switches into the guest session.
      *
      * @param guestName Username for the guest user.
      * @return {@code true} if switch to guest user succeed.
      */
     public boolean startNewGuestSession(String guestName) {
         UserInfo guest = mUserManager.createGuest(mContext, guestName);
         if (guest == null) {
             // Couldn't create user, most likely because there are too many, but we haven't
             // been able to reload the list yet.
             Log.w(TAG, "can't create user.");
             return false;
         }
         assignDefaultIcon(guest);
         return switchToUserId(guest.id);
     }

     /**
      * Gets a bitmap representing the user's default avatar.
      *
      * @param userInfo User whose avatar should be returned.
      * @return Default user icon
      */
     public Bitmap getUserDefaultIcon(UserInfo userInfo) {
         return UserIcons.convertToBitmap(
             UserIcons.getDefaultUserIcon(mContext.getResources(), userInfo.id, false));
     }

     /**
      * Gets a bitmap representing the default icon for a Guest user.
      *
      * @return Default guest user icon
      */
     public Bitmap getGuestDefaultIcon() {
         if (mDefaultGuestUserIcon == null) {
             mDefaultGuestUserIcon = UserIcons.convertToBitmap(UserIcons.getDefaultUserIcon(
                 mContext.getResources(), UserHandle.USER_NULL, false));
         }
         return mDefaultGuestUserIcon;
     }

     /**
      * Gets an icon for the user.
      *
      * @param userInfo User for which we want to get the icon.
      * @return a Bitmap for the icon
      */
     public Bitmap getUserIcon(UserInfo userInfo) {
         Bitmap picture = mUserManager.getUserIcon(userInfo.id);

         if (picture == null) {
             return assignDefaultIcon(userInfo);
         }

         return picture;
     }

     /**
      * Method for scaling a Bitmap icon to a desirable size.
      *
      * @param icon Bitmap to scale.
      * @param desiredSize Wanted size for the icon.
      * @return Drawable for the icon, scaled to the new size.
      */
     public Drawable scaleUserIcon(Bitmap icon, int desiredSize) {
         Bitmap scaledIcon = Bitmap.createScaledBitmap(
                 icon, desiredSize, desiredSize, true /* filter */);
         return new BitmapDrawable(mContext.getResources(), scaledIcon);
     }

     /**
      * Sets new Username for the user.
      *
      * @param user User whose name should be changed.
      * @param name New username.
      */
     public void setUserName(UserInfo user, String name) {
         mUserManager.setUserName(user.id, name);
     }

     private void registerReceiver() {
         IntentFilter filter = new IntentFilter();
         filter.addAction(Intent.ACTION_USER_REMOVED);
         filter.addAction(Intent.ACTION_USER_ADDED);
         filter.addAction(Intent.ACTION_USER_INFO_CHANGED);
         filter.addAction(Intent.ACTION_USER_SWITCHED);
         filter.addAction(Intent.ACTION_USER_STOPPED);
         filter.addAction(Intent.ACTION_USER_UNLOCKED);
         mContext.registerReceiverAsUser(mUserChangeReceiver, UserHandle.ALL, filter, null, null);
     }

     // Assigns a default icon to a user according to the user's id.
     private Bitmap assignDefaultIcon(UserInfo userInfo) {
         Bitmap bitmap = userInfo.isGuest()
                 ? getGuestDefaultIcon() : getUserDefaultIcon(userInfo);
         mUserManager.setUserIcon(userInfo.id, bitmap);
         return bitmap;
     }

     private void unregisterReceiver() {
         mContext.unregisterReceiver(mUserChangeReceiver);
     }

     /**
      * Interface for listeners that want to register for receiving updates to changes to the users
      * on the system including removing and adding users, and changing user info.
      */
     public interface OnUsersUpdateListener {
         /**
          * Method that will get called when users list has been changed.
          */
         void onUsersUpdate();
     }
 }
	/*
	* Copyright (C) 2018 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.car.user;

	import android.annotation.Nullable;
	import android.app.ActivityManager;
	import android.car.settings.CarSettings;
	import android.content.BroadcastReceiver;
	import android.content.Context;
	import android.content.Intent;
	import android.content.IntentFilter;
	import android.content.pm.UserInfo;
	import android.graphics.Bitmap;
	import android.graphics.drawable.BitmapDrawable;
	import android.graphics.drawable.Drawable;
	import android.os.SystemProperties;
	import android.os.UserHandle;
	import android.os.UserManager;
	import android.util.Log;

	import com.android.internal.util.UserIcons;

	import java.util.Iterator;
	import java.util.List;

	/**
	* Helper class for {@link UserManager}, this is meant to be used by builds that support
	* Multi-user model with headless user 0. User 0 is not associated with a real person, and
	* can not be brought to foreground.
	*
	* <p>This class provides method for user management, including creating, removing, adding
	* and switching users. Methods related to get users will exclude system user by default.
	*
	* @hide
	*/
	public class CarUserManagerHelper {
	private static final String TAG = "CarUserManagerHelper";
	private static final String HEADLESS_SYSTEM_USER = "android.car.systemuser.headless";
	private final Context mContext;
	private final UserManager mUserManager;
	private final ActivityManager mActivityManager;
	private Bitmap mDefaultGuestUserIcon;
	private OnUsersUpdateListener mUpdateListener;
	private final BroadcastReceiver mUserChangeReceiver = new BroadcastReceiver() {
	@Override
	public void onReceive(Context context, Intent intent) {
	mUpdateListener.onUsersUpdate();
	}
	};

	public CarUserManagerHelper(Context context) {
	mContext = context.getApplicationContext();
	mUserManager = (UserManager) mContext.getSystemService(Context.USER_SERVICE);
	mActivityManager = (ActivityManager) mContext.getSystemService(Context.ACTIVITY_SERVICE);
	}

	/**
	* Registers a listener for updates to all users - removing, adding users or changing user info.
	*
	* <p> Best practise is to keep one listener per helper.
	*
	* @param listener Instance of {@link OnUsersUpdateListener}.
	*/
	public void registerOnUsersUpdateListener(OnUsersUpdateListener listener) {
	if (mUpdateListener != null) {
	unregisterOnUsersUpdateListener();
	}

	mUpdateListener = listener;
	registerReceiver();
	}

	/**
	* Unregisters on user update listener by unregistering {@code BroadcastReceiver}.
	*/
	public void unregisterOnUsersUpdateListener() {
	unregisterReceiver();
	}

	/**
	* Returns {@code true} if the system is in the headless user 0 model.
	*
	* @return {@boolean true} if headless system user.
	*/
	public boolean isHeadlessSystemUser() {
	return SystemProperties.getBoolean(HEADLESS_SYSTEM_USER, false);
	}

	/**
	* Gets UserInfo for the system user.
	*
	* @return {@link UserInfo} for the system user.
	*/
	public UserInfo getSystemUserInfo() {
	return mUserManager.getUserInfo(UserHandle.USER_SYSTEM);
	}

	/**
	* Gets UserInfo for the current foreground user.
	*
	* Concept of foreground user is relevant for the multi-user deployment. Foreground user
	* corresponds to the currently "logged in" user.
	*
	* @return {@link UserInfo} for the foreground user.
	*/
	public UserInfo getCurrentForegroundUserInfo() {
	return mUserManager.getUserInfo(getCurrentForegroundUserId());
	}

	/**
	* @return Id of the current foreground user.
	*/
	public int getCurrentForegroundUserId() {
	return mActivityManager.getCurrentUser();
	}

	/**
	* Gets UserInfo for the user running the caller process.
	*
	* <p>Differentiation between foreground user and current process user is relevant for
	* multi-user deployments.
	*
	* <p>Some multi-user aware components (like SystemUI) needs to run a singleton component
	* in system user. Current process user is always the same for that component, even when
	* the foreground user changes.
	*
	* @return {@link UserInfo} for the user running the current process.
	*/
	public UserInfo getCurrentProcessUserInfo() {
	return mUserManager.getUserInfo(getCurrentProcessUserId());
	}

	/**
	* @return Id for the user running the current process.
	*/
	public int getCurrentProcessUserId() {
	return UserHandle.myUserId();
	}

	/**
	* Gets all the existing foreground users on the system that are not currently running as
	* the foreground user.
	*
	* @return List of {@code UserInfo} for each user that is not the foreground user.
	*/
	public List<UserInfo> getAllSwitchableUsers() {
	if (isHeadlessSystemUser()) {
	return getAllUsersExceptSystemUserAndSpecifiedUser(getCurrentForegroundUserId());
	} else {
	return getAllUsersExceptSpecifiedUser(getCurrentForegroundUserId());
	}
	}

	/**
	* Gets all the users that can be brought to the foreground on the system.
	*
	* @return List of {@code UserInfo} for users that associated with a real person.
	*/
	public List<UserInfo> getAllUsers() {
	if (isHeadlessSystemUser()) {
	return getAllUsersExceptSystemUserAndSpecifiedUser(UserHandle.USER_SYSTEM);
	} else {
	return mUserManager.getUsers(/* excludeDying= */true);
	}
	}

	/**
	* Get all the users except the one with userId passed in.
	*
	* @param userId of the user not to be returned.
	* @return All users other than user with userId.
	*/
	private List<UserInfo> getAllUsersExceptSpecifiedUser(int userId) {
	List<UserInfo> users = mUserManager.getUsers(/* excludeDying= */true);

	for (Iterator<UserInfo> iterator = users.iterator(); iterator.hasNext(); ) {
	UserInfo userInfo = iterator.next();
	if (userInfo.id == userId) {
	// Remove user with userId from the list.
	iterator.remove();
	}
	}
	return users;
	}

	/**
	* Get all the users except system user and the one with userId passed in.
	*
	* @param userId of the user not to be returned.
	* @return All users other than system user and user with userId.
	*/
	private List<UserInfo> getAllUsersExceptSystemUserAndSpecifiedUser(int userId) {
	List<UserInfo> users = mUserManager.getUsers(/* excludeDying= */true);

	for (Iterator<UserInfo> iterator = users.iterator(); iterator.hasNext(); ) {
	UserInfo userInfo = iterator.next();
	if (userInfo.id == userId \|\| userInfo.id == UserHandle.USER_SYSTEM) {
	// Remove user with userId from the list.
	iterator.remove();
	}
	}
	return users;
	}

	// User information accessors

	/**
	* Checks whether the user is system user.
	*
	* @param userInfo User to check against system user.
	* @return {@code true} if system user, {@code false} otherwise.
	*/
	public boolean isSystemUser(UserInfo userInfo) {
	return userInfo.id == UserHandle.USER_SYSTEM;
	}

	/**
	* Checks whether the user is default user.
	*
	* @param userInfo User to check against system user.
	* @return {@code true} if is default user, {@code false} otherwise.
	*/
	public boolean isDefaultUser(UserInfo userInfo) {
	return userInfo.id == CarSettings.DEFAULT_USER_ID_TO_BOOT_INTO;
	}

	/**
	* Checks whether passed in user is the foreground user.
	*
	* @param userInfo User to check.
	* @return {@code true} if foreground user, {@code false} otherwise.
	*/
	public boolean isForegroundUser(UserInfo userInfo) {
	return getCurrentForegroundUserId() == userInfo.id;
	}

	/**
	* Checks whether passed in user is the user that's running the current process.
	*
	* @param userInfo User to check.
	* @return {@code true} if user running the process, {@code false} otherwise.
	*/
	public boolean isCurrentProcessUser(UserInfo userInfo) {
	return getCurrentProcessUserId() == userInfo.id;
	}

	// Foreground user information accessors.

	/**
	* Checks if the foreground user is a guest user.
	*/
	public boolean isForegroundUserGuest() {
	return getCurrentForegroundUserInfo().isGuest();
	}

	/**
	* Returns whether this user can be removed from the system.
	*
	* @param userInfo User to be removed
	* @return {@code true} if they can be removed, {@code false} otherwise.
	*/
	public boolean canUserBeRemoved(UserInfo userInfo) {
	return !isSystemUser(userInfo);
	}

	/**
	* Return whether the foreground user has a restriction.
	*
	* @param restriction Restriction to check. Should be a UserManager.* restriction.
	* @return Whether that restriction exists for the foreground user.
	*/
	public boolean foregroundUserHasUserRestriction(String restriction) {
	return mUserManager.hasUserRestriction(
	restriction, getCurrentForegroundUserInfo().getUserHandle());
	}

	/**
	* Checks if the foreground user can add new users.
	*/
	public boolean canForegroundUserAddUsers() {
	return !foregroundUserHasUserRestriction(UserManager.DISALLOW_ADD_USER);
	}

	// Current process user information accessors

	/**
	* Checks whether this process is running under the system user.
	*/
	public boolean isCurrentProcessSystemUser() {
	return mUserManager.isSystemUser();
	}

	/**
	* Checks if the calling app is running in a demo user.
	*/
	public boolean isCurrentProcessDemoUser() {
	return mUserManager.isDemoUser();
	}

	/**
	* Checks if the calling app is running as a guest user.
	*/
	public boolean isCurrentProcessGuestUser() {
	return mUserManager.isGuestUser();
	}

	/**
	* Check is the calling app is running as a restricted profile user (ie. a LinkedUser).
	* Restricted profiles are only available when {@link #isHeadlessSystemUser()} is false.
	*/
	public boolean isCurrentProcessRestrictedProfileUser() {
	return mUserManager.isRestrictedProfile();
	}

	// Current process user restriction accessors

	/**
	* Return whether the user running the current process has a restriction.
	*
	* @param restriction Restriction to check. Should be a UserManager.* restriction.
	* @return Whether that restriction exists for the user running the process.
	*/
	public boolean isCurrentProcessUserHasRestriction(String restriction) {
	return mUserManager.hasUserRestriction(restriction);
	}

	/**
	* Checks if the current process user can modify accounts. Demo and Guest users cannot modify
	* accounts even if the DISALLOW_MODIFY_ACCOUNTS restriction is not applied.
	*/
	public boolean canCurrentProcessModifyAccounts() {
	return !isCurrentProcessUserHasRestriction(UserManager.DISALLOW_MODIFY_ACCOUNTS)
	&& !isCurrentProcessDemoUser()
	&& !isCurrentProcessGuestUser();
	}

	/**
	* Checks if the user running the current process can add new users.
	*/
	public boolean canCurrentProcessAddUsers() {
	return !isCurrentProcessUserHasRestriction(UserManager.DISALLOW_ADD_USER);
	}

	/**
	* Checks if the user running the current process can remove users.
	*/
	public boolean canCurrentProcessRemoveUsers() {
	return !isCurrentProcessUserHasRestriction(UserManager.DISALLOW_REMOVE_USER);
	}

	/**
	* Checks if the user running the current process is allowed to switch to another user.
	*/
	public boolean canCurrentProcessSwitchUsers() {
	return !isCurrentProcessUserHasRestriction(UserManager.DISALLOW_USER_SWITCH);
	}

	/**
	* Creates a new user on the system, the created user would be granted admin role.
	*
	* @param userName Name to give to the newly created user.
	* @return Newly created admin user, null if failed to create a user.
	*/
	@Nullable
	public UserInfo createNewAdminUser(String userName) {
	UserInfo user = mUserManager.createUser(userName, UserInfo.FLAG_ADMIN);
	if (user == null) {
	// Couldn't create user, most likely because there are too many, but we haven't
	// been able to reload the list yet.
	Log.w(TAG, "can't create admin user.");
	return null;
	}
	assignDefaultIcon(user);
	return user;
	}

	/**
	* Creates a new restricted user on the system.
	*
	* @param userName Name to give to the newly created user.
	* @return Newly created restricted user, null if failed to create a user.
	*/
	@Nullable
	public UserInfo createNewNonAdminUser(String userName) {
	UserInfo user = mUserManager.createUser(userName, 0);
	if (user == null) {
	// Couldn't create user, most likely because there are too many, but we haven't
	// been able to reload the list yet.
	Log.w(TAG, "can't create non-admin user.");
	return null;
	}
	assignDefaultIcon(user);
	return user;
	}

	/**
	* Tries to remove the user that's passed in. System user cannot be removed.
	* If the user to be removed is user currently running the process,
	* it switches to the guest user first, and then removes the user.
	*
	* @param userInfo User to be removed
	* @return {@code true} if user is successfully removed, {@code false} otherwise.
	*/
	public boolean removeUser(UserInfo userInfo, String guestUserName) {
	if (isSystemUser(userInfo)) {
	Log.w(TAG, "User " + userInfo.id + " is system user, could not be removed.");
	return false;
	}

	// Not allow to delete the default user for now. Since default user is the one to
	// boot into.
	if (isHeadlessSystemUser() && isDefaultUser(userInfo)) {
	Log.w(TAG, "User " + userInfo.id + " is the default user, could not be removed.");
	return false;
	}

	if (userInfo.id == getCurrentForegroundUserId()) {
	startNewGuestSession(guestUserName);
	}

	return mUserManager.removeUser(userInfo.id);
	}

	/**
	* Switches (logs in) to another user given user id.
	*
	* @param id User id to switch to.
	* @return {@code true} if user switching succeed.
	*/
	public boolean switchToUserId(int id) {
	if (id == UserHandle.USER_SYSTEM && isHeadlessSystemUser()) {
	// System User doesn't associate with real person, can not be switched to.
	return false;
	}
	return mActivityManager.switchUser(id);
	}

	/**
	* Switches (logs in) to another user.
	*
	* @param userInfo User to switch to.
	* @return {@code true} if user switching succeed.
	*/
	public boolean switchToUser(UserInfo userInfo) {
	if (userInfo.id == getCurrentForegroundUserId()) {
	return false;
	}

	return switchToUserId(userInfo.id);
	}

	/**
	* Creates a new guest session and switches into the guest session.
	*
	* @param guestName Username for the guest user.
	* @return {@code true} if switch to guest user succeed.
	*/
	public boolean startNewGuestSession(String guestName) {
	UserInfo guest = mUserManager.createGuest(mContext, guestName);
	if (guest == null) {
	// Couldn't create user, most likely because there are too many, but we haven't
	// been able to reload the list yet.
	Log.w(TAG, "can't create user.");
	return false;
	}
	assignDefaultIcon(guest);
	return switchToUserId(guest.id);
	}

	/**
	* Gets a bitmap representing the user's default avatar.
	*
	* @param userInfo User whose avatar should be returned.
	* @return Default user icon
	*/
	public Bitmap getUserDefaultIcon(UserInfo userInfo) {
	return UserIcons.convertToBitmap(
	UserIcons.getDefaultUserIcon(mContext.getResources(), userInfo.id, false));
	}

	/**
	* Gets a bitmap representing the default icon for a Guest user.
	*
	* @return Default guest user icon
	*/
	public Bitmap getGuestDefaultIcon() {
	if (mDefaultGuestUserIcon == null) {
	mDefaultGuestUserIcon = UserIcons.convertToBitmap(UserIcons.getDefaultUserIcon(
	mContext.getResources(), UserHandle.USER_NULL, false));
	}
	return mDefaultGuestUserIcon;
	}

	/**
	* Gets an icon for the user.
	*
	* @param userInfo User for which we want to get the icon.
	* @return a Bitmap for the icon
	*/
	public Bitmap getUserIcon(UserInfo userInfo) {
	Bitmap picture = mUserManager.getUserIcon(userInfo.id);

	if (picture == null) {
	return assignDefaultIcon(userInfo);
	}

	return picture;
	}

	/**
	* Method for scaling a Bitmap icon to a desirable size.
	*
	* @param icon Bitmap to scale.
	* @param desiredSize Wanted size for the icon.
	* @return Drawable for the icon, scaled to the new size.
	*/
	public Drawable scaleUserIcon(Bitmap icon, int desiredSize) {
	Bitmap scaledIcon = Bitmap.createScaledBitmap(
	icon, desiredSize, desiredSize, true /* filter */);
	return new BitmapDrawable(mContext.getResources(), scaledIcon);
	}

	/**
	* Sets new Username for the user.
	*
	* @param user User whose name should be changed.
	* @param name New username.
	*/
	public void setUserName(UserInfo user, String name) {
	mUserManager.setUserName(user.id, name);
	}

	private void registerReceiver() {
	IntentFilter filter = new IntentFilter();
	filter.addAction(Intent.ACTION_USER_REMOVED);
	filter.addAction(Intent.ACTION_USER_ADDED);
	filter.addAction(Intent.ACTION_USER_INFO_CHANGED);
	filter.addAction(Intent.ACTION_USER_SWITCHED);
	filter.addAction(Intent.ACTION_USER_STOPPED);
	filter.addAction(Intent.ACTION_USER_UNLOCKED);
	mContext.registerReceiverAsUser(mUserChangeReceiver, UserHandle.ALL, filter, null, null);
	}

	// Assigns a default icon to a user according to the user's id.
	private Bitmap assignDefaultIcon(UserInfo userInfo) {
	Bitmap bitmap = userInfo.isGuest()
	? getGuestDefaultIcon() : getUserDefaultIcon(userInfo);
	mUserManager.setUserIcon(userInfo.id, bitmap);
	return bitmap;
	}

	private void unregisterReceiver() {
	mContext.unregisterReceiver(mUserChangeReceiver);
	}

	/**
	* Interface for listeners that want to register for receiving updates to changes to the users
	* on the system including removing and adding users, and changing user info.
	*/
	public interface OnUsersUpdateListener {
	/**
	* Method that will get called when users list has been changed.
	*/
	void onUsersUpdate();
	}
	}