impl/keyguard/KeyguardHostView.java

/*
 * Copyright (C) 2012 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.internal.policy.impl.keyguard;

import android.app.Activity;
import android.app.ActivityManager;
import android.app.ActivityOptions;
import android.app.AlertDialog;
import android.app.admin.DevicePolicyManager;
import android.appwidget.AppWidgetHost;
import android.appwidget.AppWidgetHostView;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProviderInfo;
import android.content.Context;
import android.content.Intent;
import android.content.IntentSender;
import android.content.pm.UserInfo;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.os.Looper;
import android.os.UserHandle;
import android.os.UserManager;
import android.util.AttributeSet;
import android.util.Log;
import android.util.Slog;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.view.animation.AnimationUtils;
import android.widget.RemoteViews.OnClickHandler;
import android.widget.ViewFlipper;

import com.android.internal.R;
import com.android.internal.policy.impl.keyguard.KeyguardSecurityModel.SecurityMode;
import com.android.internal.widget.LockPatternUtils;

import java.io.File;
import java.util.List;

public class KeyguardHostView extends KeyguardViewBase {
    private static final String TAG = "KeyguardViewHost";

    // Use this to debug all of keyguard
    public static boolean DEBUG;

    // also referenced in SecuritySettings.java
    static final int APPWIDGET_HOST_ID = 0x4B455947;
    private static final String KEYGUARD_WIDGET_PREFS = "keyguard_widget_prefs";

    private AppWidgetHost mAppWidgetHost;
    private KeyguardWidgetPager mAppWidgetContainer;
    private ViewFlipper mSecurityViewContainer;
    private boolean mEnableMenuKey;
    private boolean mIsVerifyUnlockOnly;
    private boolean mEnableFallback; // TODO: This should get the value from KeyguardPatternView
    private SecurityMode mCurrentSecuritySelection = SecurityMode.None;

    protected Runnable mLaunchRunnable;

    protected int mFailedAttempts;
    private LockPatternUtils mLockPatternUtils;

    private KeyguardSecurityModel mSecurityModel;

    private Rect mTempRect = new Rect();
    private KeyguardTransportControlView mTransportControl;

    /*package*/ interface TransportCallback {
        void hide();
        void show();
    }

    /*package*/ interface UserSwitcherCallback {
        void hideSecurityView(int duration);
        void showSecurityView();
    }

    public KeyguardHostView(Context context) {
        this(context, null);
    }

    public KeyguardHostView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mLockPatternUtils = new LockPatternUtils(context);
        mAppWidgetHost = new AppWidgetHost(
                context, APPWIDGET_HOST_ID, mOnClickHandler, Looper.myLooper());
        mSecurityModel = new KeyguardSecurityModel(context);

        // The following enables the MENU key to work for testing automation
        mEnableMenuKey = shouldEnableMenuKey();
        setFocusable(true);
        setFocusableInTouchMode(true);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        boolean result = super.onTouchEvent(ev);
        mTempRect.set(0, 0, 0, 0);
        offsetRectIntoDescendantCoords(mSecurityViewContainer, mTempRect);
        ev.offsetLocation(mTempRect.left, mTempRect.top);
        result = mSecurityViewContainer.dispatchTouchEvent(ev) || result;
        ev.offsetLocation(-mTempRect.left, -mTempRect.top);
        return result;
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        super.dispatchDraw(canvas);
        mViewMediatorCallback.keyguardDoneDrawing();
    }

    private int getWidgetPosition(int id) {
        final int children = mAppWidgetContainer.getChildCount();
        for (int i = 0; i < children; i++) {
            if (mAppWidgetContainer.getChildAt(i).getId() == id) {
                return i;
            }
        }
        return -1;
    }

    @Override
    protected void onFinishInflate() {
        mAppWidgetContainer = (KeyguardWidgetPager) findViewById(R.id.app_widget_container);
        mAppWidgetContainer.setVisibility(VISIBLE);
        mSecurityViewContainer = (ViewFlipper) findViewById(R.id.view_flipper);

        // This code manages showing/hiding the transport control. We keep it around and only
        // add it to the hierarchy if it needs to be present.
        mTransportControl =
                (KeyguardTransportControlView) findViewById(R.id.keyguard_transport_control);
        if (mTransportControl != null) {
            mTransportControl.setKeyguardCallback(new TransportCallback() {
                boolean mSticky = false;
                @Override
                public void hide() {
                    int page = getWidgetPosition(R.id.keyguard_transport_control);
                    if (page != -1 && !mSticky) {
                        if (page == mAppWidgetContainer.getCurrentPage()) {
                            // Switch back to clock view if music was showing.
                            mAppWidgetContainer
                                .setCurrentPage(getWidgetPosition(R.id.keyguard_status_view));
                        }
                        mAppWidgetContainer.removeView(mTransportControl);
                        // XXX keep view attached to hierarchy so we still get show/hide events
                        // from AudioManager
                        KeyguardHostView.this.addView(mTransportControl);
                        mTransportControl.setVisibility(View.GONE);
                    }
                }

                @Override
                public void show() {
                    if (getWidgetPosition(R.id.keyguard_transport_control) == -1) {
                        KeyguardHostView.this.removeView(mTransportControl);
                        mAppWidgetContainer.addView(mTransportControl,
                                getWidgetPosition(R.id.keyguard_status_view) + 1);
                        mTransportControl.setVisibility(View.VISIBLE);
                        // Once shown, leave it showing
                        mSticky = true;
                    }
                }
            });
        }
        updateSecurityViews();
        setSystemUiVisibility(getSystemUiVisibility() | View.STATUS_BAR_DISABLE_BACK);
    }

    private void updateSecurityViews() {
        int children = mSecurityViewContainer.getChildCount();
        for (int i = 0; i < children; i++) {
            updateSecurityView(mSecurityViewContainer.getChildAt(i));
        }
    }

    private void updateSecurityView(View view) {
        if (view instanceof KeyguardSecurityView) {
            KeyguardSecurityView ksv = (KeyguardSecurityView) view;
            ksv.setKeyguardCallback(mCallback);
            ksv.setLockPatternUtils(mLockPatternUtils);
        } else {
            Log.w(TAG, "View " + view + " is not a KeyguardSecurityView");
        }
    }

    void setLockPatternUtils(LockPatternUtils utils) {
        mSecurityModel.setLockPatternUtils(utils);
        mLockPatternUtils = utils;
        updateSecurityViews();
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        mAppWidgetHost.startListening();
        maybePopulateWidgets();
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        mAppWidgetHost.stopListening();
    }

    private AppWidgetHost getAppWidgetHost() {
        return mAppWidgetHost;
    }

    void addWidget(AppWidgetHostView view) {
        mAppWidgetContainer.addWidget(view);
    }

    private KeyguardSecurityCallback mCallback = new KeyguardSecurityCallback() {

        public void userActivity(long timeout) {
            mViewMediatorCallback.pokeWakelock(timeout);
        }

        public void dismiss(boolean authenticated) {
            showNextSecurityScreenOrFinish(authenticated);
        }

        public boolean isVerifyUnlockOnly() {
            return mIsVerifyUnlockOnly;
        }

        public void reportSuccessfulUnlockAttempt() {
            KeyguardUpdateMonitor.getInstance(mContext).clearFailedUnlockAttempts();
        }

        public void reportFailedUnlockAttempt() {
            // TODO: handle biometric attempt differently.
            KeyguardHostView.this.reportFailedUnlockAttempt();
        }

        public int getFailedAttempts() {
            return KeyguardUpdateMonitor.getInstance(mContext).getFailedUnlockAttempts();
        }

        @Override
        public void showBackupSecurity() {
            KeyguardHostView.this.showBackupSecurity();
        }

        @Override
        public void setOnDismissRunnable(Runnable runnable) {
            KeyguardHostView.this.setOnDismissRunnable(runnable);
        }

    };

    private void showDialog(String title, String message) {
        final AlertDialog dialog = new AlertDialog.Builder(mContext)
            .setTitle(title)
            .setMessage(message)
            .setNeutralButton(com.android.internal.R.string.ok, null)
            .create();
        if (!(mContext instanceof Activity)) {
            dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);
        }
        dialog.show();
    }

    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        if (event.getAction() == KeyEvent.ACTION_UP
                && event.getKeyCode() == KeyEvent.KEYCODE_BACK
                && mCurrentSecuritySelection != SecurityMode.None) {
            mCallback.dismiss(false);
            return true;
        }
        return super.dispatchKeyEvent(event);
    }

    private void showTimeoutDialog() {
        int timeoutInSeconds = (int) LockPatternUtils.FAILED_ATTEMPT_TIMEOUT_MS / 1000;
        int messageId = 0;

        switch (mSecurityModel.getSecurityMode()) {
            case Pattern:
                messageId = R.string.kg_too_many_failed_pattern_attempts_dialog_message;
                break;

            case Password: {
                    final boolean isPin = mLockPatternUtils.getKeyguardStoredPasswordQuality() ==
                        DevicePolicyManager.PASSWORD_QUALITY_NUMERIC;
                    messageId = isPin ? R.string.kg_too_many_failed_pin_attempts_dialog_message
                            : R.string.kg_too_many_failed_password_attempts_dialog_message;
                }
                break;
        }

        if (messageId != 0) {
            final String message = mContext.getString(messageId,
                    KeyguardUpdateMonitor.getInstance(mContext).getFailedUnlockAttempts(),
                    timeoutInSeconds);
            showDialog(null, message);
        }
    }

    private void showAlmostAtWipeDialog(int attempts, int remaining) {
        int timeoutInSeconds = (int) LockPatternUtils.FAILED_ATTEMPT_TIMEOUT_MS / 1000;
        String message = mContext.getString(R.string.kg_failed_attempts_almost_at_wipe,
                attempts, remaining);
        showDialog(null, message);
    }

    private void showWipeDialog(int attempts) {
        String message = mContext.getString(R.string.kg_failed_attempts_now_wiping, attempts);
        showDialog(null, message);
    }

    private void showAlmostAtAccountLoginDialog() {
        final int timeoutInSeconds = (int) LockPatternUtils.FAILED_ATTEMPT_TIMEOUT_MS / 1000;
        final int count = LockPatternUtils.FAILED_ATTEMPTS_BEFORE_RESET
                - LockPatternUtils.FAILED_ATTEMPTS_BEFORE_TIMEOUT;
        String message = mContext.getString(R.string.kg_failed_attempts_almost_at_login,
                count, LockPatternUtils.FAILED_ATTEMPTS_BEFORE_TIMEOUT, timeoutInSeconds);
        showDialog(null, message);
    }

    private void reportFailedUnlockAttempt() {
        final KeyguardUpdateMonitor monitor = KeyguardUpdateMonitor.getInstance(mContext);
        final int failedAttempts = monitor.getFailedUnlockAttempts() + 1; // +1 for this time

        if (DEBUG) Log.d(TAG, "reportFailedPatternAttempt: #" + failedAttempts);

        SecurityMode mode = mSecurityModel.getSecurityMode();
        final boolean usingPattern = mode == KeyguardSecurityModel.SecurityMode.Pattern;

        final int failedAttemptsBeforeWipe = mLockPatternUtils.getDevicePolicyManager()
                .getMaximumFailedPasswordsForWipe(null, mLockPatternUtils.getCurrentUser());

        final int failedAttemptWarning = LockPatternUtils.FAILED_ATTEMPTS_BEFORE_RESET
                - LockPatternUtils.FAILED_ATTEMPTS_BEFORE_TIMEOUT;

        final int remainingBeforeWipe = failedAttemptsBeforeWipe > 0 ?
                (failedAttemptsBeforeWipe - failedAttempts)
                : Integer.MAX_VALUE; // because DPM returns 0 if no restriction

        boolean showTimeout = false;
        if (remainingBeforeWipe < LockPatternUtils.FAILED_ATTEMPTS_BEFORE_WIPE_GRACE) {
            // If we reach this code, it means the user has installed a DevicePolicyManager
            // that requests device wipe after N attempts.  Once we get below the grace
            // period, we'll post this dialog every time as a clear warning until the
            // bombshell hits and the device is wiped.
            if (remainingBeforeWipe > 0) {
                showAlmostAtWipeDialog(failedAttempts, remainingBeforeWipe);
            } else {
                // Too many attempts. The device will be wiped shortly.
                Slog.i(TAG, "Too many unlock attempts; device will be wiped!");
                showWipeDialog(failedAttempts);
            }
        } else {
            showTimeout =
                (failedAttempts % LockPatternUtils.FAILED_ATTEMPTS_BEFORE_TIMEOUT) == 0;
            if (usingPattern && mEnableFallback) {
                if (failedAttempts == failedAttemptWarning) {
                    showAlmostAtAccountLoginDialog();
                    showTimeout = false; // don't show both dialogs
                } else if (failedAttempts >= LockPatternUtils.FAILED_ATTEMPTS_BEFORE_RESET) {
                    mLockPatternUtils.setPermanentlyLocked(true);
                    showSecurityScreen(SecurityMode.Account);
                    // don't show timeout dialog because we show account unlock screen next
                    showTimeout = false;
                }
            }
        }
        monitor.reportFailedUnlockAttempt();
        mLockPatternUtils.reportFailedPasswordAttempt();
        if (showTimeout) {
            showTimeoutDialog();
        }
    }

    /**
     * Shows the backup security screen for the current security mode.  This could be used for
     * password recovery screens but is currently only used for pattern unlock to show the
     * account unlock screen and biometric unlock to show the user's normal unlock.
     */
    private void showBackupSecurity() {
        SecurityMode currentMode = mSecurityModel.getAlternateFor(mSecurityModel.getSecurityMode());
        showSecurityScreen(mSecurityModel.getBackupFor(currentMode));
    }

    private void showNextSecurityScreenOrFinish(boolean authenticated) {
        boolean finish = false;
        if (SecurityMode.None == mCurrentSecuritySelection) {
            SecurityMode securityMode = mSecurityModel.getSecurityMode();
            // Allow an alternate, such as biometric unlock
            securityMode = mSecurityModel.getAlternateFor(securityMode);
            if (SecurityMode.None == securityMode) {
                finish = true; // no security required
            } else {
                showSecurityScreen(securityMode); // switch to the alternate security view
            }
        } else if (authenticated) {
            switch (mCurrentSecuritySelection) {
                case Pattern:
                case Password:
                case Account:
                case Biometric:
                    finish = true;
                    break;

                case SimPin:
                case SimPuk:
                    // Shortcut for SIM PIN/PUK to go to directly to user's security screen or home
                    SecurityMode securityMode = mSecurityModel.getSecurityMode();
                    if (securityMode != SecurityMode.None) {
                        showSecurityScreen(securityMode);
                    } else {
                        finish = true;
                    }
                    break;

                default:
                    showSecurityScreen(SecurityMode.None);
                    break;
            }
        } else {
            // Not authenticated but we were asked to dismiss so go back to selector screen.
            showSecurityScreen(SecurityMode.None);
        }
        if (finish) {
            // If there's a pending runnable because the user interacted with a widget
            // and we're leaving keyguard, then run it.
            if (mLaunchRunnable != null) {
                mLaunchRunnable.run();
                mLaunchRunnable = null;
            }
            mViewMediatorCallback.keyguardDone(true);
        }
    }

    private OnClickHandler mOnClickHandler = new OnClickHandler() {
        @Override
        public boolean onClickHandler(final View view,
                final android.app.PendingIntent pendingIntent,
                final Intent fillInIntent) {
            if (pendingIntent.isActivity()) {
                setOnDismissRunnable(new Runnable() {
                    public void run() {
                        try {
                              // TODO: Unregister this handler if PendingIntent.FLAG_ONE_SHOT?
                              Context context = view.getContext();
                              ActivityOptions opts = ActivityOptions.makeScaleUpAnimation(view,
                                      0, 0,
                                      view.getMeasuredWidth(), view.getMeasuredHeight());
                              context.startIntentSender(
                                      pendingIntent.getIntentSender(), fillInIntent,
                                      Intent.FLAG_ACTIVITY_NEW_TASK,
                                      Intent.FLAG_ACTIVITY_NEW_TASK, 0, opts.toBundle());
                          } catch (IntentSender.SendIntentException e) {
                              android.util.Log.e(TAG, "Cannot send pending intent: ", e);
                          } catch (Exception e) {
                              android.util.Log.e(TAG, "Cannot send pending intent due to " +
                                      "unknown exception: ", e);
                          }
                    }
                });

                mCallback.dismiss(false);
                return true;
            } else {
                return super.onClickHandler(view, pendingIntent, fillInIntent);
            }
        };
    };

    @Override
    public void reset() {
        mIsVerifyUnlockOnly = false;
        mAppWidgetContainer.setCurrentPage(getWidgetPosition(R.id.keyguard_status_view));
        requestFocus();
    }

    /**
     *  Sets a runnable to run when keyguard is dismissed
     * @param runnable
     */
    protected void setOnDismissRunnable(Runnable runnable) {
        mLaunchRunnable = runnable;
    }

    private KeyguardSecurityView getSecurityView(SecurityMode securityMode) {
        final int securityViewIdForMode = getSecurityViewIdForMode(securityMode);
        KeyguardSecurityView view = null;
        final int children = mSecurityViewContainer.getChildCount();
        for (int child = 0; child < children; child++) {
            if (mSecurityViewContainer.getChildAt(child).getId() == securityViewIdForMode) {
                view = ((KeyguardSecurityView)mSecurityViewContainer.getChildAt(child));
                break;
            }
        }
        if (view == null) {
            final LayoutInflater inflater = LayoutInflater.from(mContext);
            View v = inflater.inflate(getLayoutIdFor(securityMode), this, false);
            mSecurityViewContainer.addView(v);
            updateSecurityView(v);
            view = (KeyguardSecurityView) v;
        }
        return view;
    }

    /**
     * Switches to the given security view unless it's already being shown, in which case
     * this is a no-op.
     *
     * @param securityMode
     */
    private void showSecurityScreen(SecurityMode securityMode) {

        if (securityMode == mCurrentSecuritySelection) return;

        KeyguardSecurityView oldView = getSecurityView(mCurrentSecuritySelection);
        KeyguardSecurityView newView = getSecurityView(securityMode);

        // Emulate Activity life cycle
        oldView.onPause();
        newView.onResume();

        mViewMediatorCallback.setNeedsInput(newView.needsInput());

        // Find and show this child.
        final int childCount = mSecurityViewContainer.getChildCount();

        // If we're go to/from the selector view, do flip animation, otherwise use fade animation.
        final boolean doFlip = mCurrentSecuritySelection == SecurityMode.None
                || securityMode == SecurityMode.None;
        final int inAnimation = doFlip ? R.anim.keyguard_security_animate_in
                : R.anim.keyguard_security_fade_in;
        final int outAnimation = doFlip ? R.anim.keyguard_security_animate_out
                : R.anim.keyguard_security_fade_out;

        mSecurityViewContainer.setInAnimation(AnimationUtils.loadAnimation(mContext, inAnimation));
        mSecurityViewContainer.setOutAnimation(AnimationUtils.loadAnimation(mContext, outAnimation));
        final int securityViewIdForMode = getSecurityViewIdForMode(securityMode);
        for (int i = 0; i < childCount; i++) {
            if (mSecurityViewContainer.getChildAt(i).getId() == securityViewIdForMode) {
                mSecurityViewContainer.setDisplayedChild(i);
                break;
            }
        }


        if (securityMode == SecurityMode.None) {
            // Discard current runnable if we're switching back to the selector view
            setOnDismissRunnable(null);
            setSystemUiVisibility(getSystemUiVisibility() | View.STATUS_BAR_DISABLE_BACK);
        } else {
            setSystemUiVisibility(getSystemUiVisibility() & (~View.STATUS_BAR_DISABLE_BACK));
        }

        mCurrentSecuritySelection = securityMode;
    }

    @Override
    public void onScreenTurnedOn() {
        if (DEBUG) Log.d(TAG, "screen on");
        showSecurityScreen(mCurrentSecuritySelection);
        getSecurityView(mCurrentSecuritySelection).onResume();

        // This is a an attempt to fix bug 7137389 where the device comes back on but the entire
        // layout is blank but forcing a layout causes it to reappear (e.g. with with
        // hierarchyviewer).
        requestLayout();
    }

    @Override
    public void onScreenTurnedOff() {
        if (DEBUG) Log.d(TAG, "screen off");
        showSecurityScreen(SecurityMode.None);
        getSecurityView(mCurrentSecuritySelection).onPause();
    }

    @Override
    public void show() {
        onScreenTurnedOn();
    }

    private boolean isSecure() {
        SecurityMode mode = mSecurityModel.getSecurityMode();
        switch (mode) {
            case Pattern:
                return mLockPatternUtils.isLockPatternEnabled();
            case Password:
                return mLockPatternUtils.isLockPasswordEnabled();
            case SimPin:
            case SimPuk:
            case Account:
                return true;
            case None:
                return false;
            default:
                throw new IllegalStateException("Unknown security mode " + mode);
        }
    }

    @Override
    public void wakeWhenReadyTq(int keyCode) {
        if (DEBUG) Log.d(TAG, "onWakeKey");
        if (keyCode == KeyEvent.KEYCODE_MENU && isSecure()) {
            if (DEBUG) Log.d(TAG, "switching screens to unlock screen because wake key was MENU");
            showSecurityScreen(SecurityMode.None);
            mViewMediatorCallback.pokeWakelock();
        } else {
            if (DEBUG) Log.d(TAG, "poking wake lock immediately");
            mViewMediatorCallback.pokeWakelock();
        }
    }

    @Override
    public void verifyUnlock() {
        SecurityMode securityMode = mSecurityModel.getSecurityMode();
        if (securityMode == KeyguardSecurityModel.SecurityMode.None) {
            mViewMediatorCallback.keyguardDone(true);
        } else if (securityMode != KeyguardSecurityModel.SecurityMode.Pattern
                && securityMode != KeyguardSecurityModel.SecurityMode.Password) {
            // can only verify unlock when in pattern/password mode
            mViewMediatorCallback.keyguardDone(false);
        } else {
            // otherwise, go to the unlock screen, see if they can verify it
            mIsVerifyUnlockOnly = true;
            showSecurityScreen(securityMode);
        }
    }

    private int getSecurityViewIdForMode(SecurityMode securityMode) {
        switch (securityMode) {
            case None: return R.id.keyguard_selector_view;
            case Pattern: return R.id.keyguard_pattern_view;
            case Password: return R.id.keyguard_password_view;
            case Biometric: return R.id.keyguard_face_unlock_view;
            case Account: return R.id.keyguard_account_view;
            case SimPin: return R.id.keyguard_sim_pin_view;
            case SimPuk: return R.id.keyguard_sim_puk_view;
        }
        return 0;
    }

    private int getLayoutIdFor(SecurityMode securityMode) {
        switch (securityMode) {
            case None: return R.layout.keyguard_selector_view;
            case Pattern: return R.layout.keyguard_pattern_view;
            case Password: return R.layout.keyguard_password_view;
            case Biometric: return R.layout.keyguard_face_unlock_view;
            case Account: return R.layout.keyguard_account_view;
            case SimPin: return R.layout.keyguard_sim_pin_view;
            case SimPuk: return R.layout.keyguard_sim_puk_view;
            default:
                throw new RuntimeException("No layout for securityMode " + securityMode);
        }
    }

    private void addWidget(int appId) {
        AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(mContext);
        AppWidgetProviderInfo appWidgetInfo = appWidgetManager.getAppWidgetInfo(appId);
        if (appWidgetInfo != null) {
            AppWidgetHostView view = getAppWidgetHost().createView(mContext, appId, appWidgetInfo);
            addWidget(view);
        } else {
            Log.w(TAG, "AppWidgetInfo was null; not adding widget id " + appId);
        }
    }

    private void maybePopulateWidgets() {
        DevicePolicyManager dpm =
                (DevicePolicyManager) mContext.getSystemService(Context.DEVICE_POLICY_SERVICE);
        if (dpm != null && dpm.getKeyguardWidgetsDisabled(null, mLockPatternUtils.getCurrentUser())
                != DevicePolicyManager.KEYGUARD_DISABLE_WIDGETS_NONE) {
            Log.v(TAG, "Keyguard widgets disabled because of device policy admin");
            return;
        }
        inflateAndAddUserSelectorWidgetIfNecessary();

        final int[] widgets = mLockPatternUtils.getUserDefinedWidgets();
        for (int i = 0; i < widgets.length; i++) {
            if (widgets[i] != -1) {
                addWidget(widgets[i]);
            }
        }
    }

    private void inflateAndAddUserSelectorWidgetIfNecessary() {
        // if there are multiple users, we need to add the multi-user switcher widget to the
        // keyguard.
        UserManager mUm = (UserManager) mContext.getSystemService(Context.USER_SERVICE);
        List<UserInfo> users = mUm.getUsers(true);

        if (users.size() > 1) {
            KeyguardWidgetFrame userSwitcher = (KeyguardWidgetFrame)
                LayoutInflater.from(mContext).inflate(R.layout.keyguard_multi_user_selector_widget,
                        mAppWidgetContainer, false);

            // add the switcher in the first position
            mAppWidgetContainer.addView(userSwitcher, getWidgetPosition(R.id.keyguard_status_view));
            KeyguardMultiUserSelectorView multiUser = (KeyguardMultiUserSelectorView)
                    userSwitcher.getChildAt(0);

            UserSwitcherCallback callback = new UserSwitcherCallback() {
                @Override
                public void hideSecurityView(int duration) {
                    mSecurityViewContainer.animate().alpha(0).setDuration(duration);
                }

                @Override
                public void showSecurityView() {
                    mSecurityViewContainer.setAlpha(1.0f);
                }
            };
            multiUser.setCallback(callback);
        }
    }

    @Override
    public void cleanUp() {

    }

    /**
     * In general, we enable unlocking the insecure keyguard with the menu key. However, there are
     * some cases where we wish to disable it, notably when the menu button placement or technology
     * is prone to false positives.
     *
     * @return true if the menu key should be enabled
     */
    private static final String ENABLE_MENU_KEY_FILE = "/data/local/enable_menu_key";
    private boolean shouldEnableMenuKey() {
        final Resources res = getResources();
        final boolean configDisabled = res.getBoolean(
                com.android.internal.R.bool.config_disableMenuKeyInLockScreen);
        final boolean isTestHarness = ActivityManager.isRunningInTestHarness();
        final boolean fileOverride = (new File(ENABLE_MENU_KEY_FILE)).exists();
        return !configDisabled || isTestHarness || fileOverride;
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_MENU && mEnableMenuKey) {
            showNextSecurityScreenOrFinish(false);
            return true;
        } else {
            return super.onKeyDown(keyCode, event);
        }
    }

}