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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.server.am;
     18 
     19 import android.app.AlertDialog;
     20 import android.content.Context;
     21 import android.content.pm.UserInfo;
     22 import android.content.res.Resources;
     23 import android.os.Handler;
     24 import android.os.Message;
     25 import android.os.UserHandle;
     26 import android.os.UserManager;
     27 import android.view.LayoutInflater;
     28 import android.view.View;
     29 import android.view.ViewTreeObserver;
     30 import android.view.WindowManager;
     31 import android.widget.TextView;
     32 
     33 import com.android.internal.R;
     34 import com.android.internal.annotations.GuardedBy;
     35 
     36 /**
     37  * Dialog to show when a user switch it about to happen. The intent is to snapshot the screen
     38  * immediately after the dialog shows so that the user is informed that something is happening
     39  * in the background rather than just freeze the screen and not know if the user-switch affordance
     40  * was being handled.
     41  */
     42 class UserSwitchingDialog extends AlertDialog
     43         implements ViewTreeObserver.OnWindowShownListener {
     44     private static final String TAG = "ActivityManagerUserSwitchingDialog";
     45 
     46     // Time to wait for the onWindowShown() callback before continuing the user switch
     47     private static final int WINDOW_SHOWN_TIMEOUT_MS = 3000;
     48 
     49     private final ActivityManagerService mService;
     50     private final int mUserId;
     51     private static final int MSG_START_USER = 1;
     52     @GuardedBy("this")
     53     private boolean mStartedUser;
     54     final protected UserInfo mOldUser;
     55     final protected UserInfo mNewUser;
     56     final private String mSwitchingFromSystemUserMessage;
     57     final private String mSwitchingToSystemUserMessage;
     58     final protected Context mContext;
     59 
     60     public UserSwitchingDialog(ActivityManagerService service, Context context, UserInfo oldUser,
     61             UserInfo newUser, boolean aboveSystem, String switchingFromSystemUserMessage,
     62             String switchingToSystemUserMessage) {
     63         super(context);
     64 
     65         mContext = context;
     66         mService = service;
     67         mUserId = newUser.id;
     68         mOldUser = oldUser;
     69         mNewUser = newUser;
     70         mSwitchingFromSystemUserMessage = switchingFromSystemUserMessage;
     71         mSwitchingToSystemUserMessage = switchingToSystemUserMessage;
     72 
     73         inflateContent();
     74 
     75         if (aboveSystem) {
     76             getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ERROR);
     77         }
     78 
     79         WindowManager.LayoutParams attrs = getWindow().getAttributes();
     80         attrs.privateFlags = WindowManager.LayoutParams.PRIVATE_FLAG_SYSTEM_ERROR |
     81             WindowManager.LayoutParams.PRIVATE_FLAG_SHOW_FOR_ALL_USERS;
     82         getWindow().setAttributes(attrs);
     83     }
     84 
     85     void inflateContent() {
     86         // Set up the dialog contents
     87         setCancelable(false);
     88         Resources res = getContext().getResources();
     89         // Custom view due to alignment and font size requirements
     90         View view = LayoutInflater.from(getContext()).inflate(R.layout.user_switching_dialog,
     91             null);
     92 
     93         String viewMessage = null;
     94         if (UserManager.isSplitSystemUser() && mNewUser.id == UserHandle.USER_SYSTEM) {
     95             viewMessage = res.getString(R.string.user_logging_out_message, mOldUser.name);
     96         } else if (UserManager.isDeviceInDemoMode(mContext)) {
     97             if (mOldUser.isDemo()) {
     98                 viewMessage = res.getString(R.string.demo_restarting_message);
     99             } else {
    100                 viewMessage = res.getString(R.string.demo_starting_message);
    101             }
    102         } else {
    103             if (mOldUser.id == UserHandle.USER_SYSTEM) {
    104                 viewMessage = mSwitchingFromSystemUserMessage;
    105             } else if (mNewUser.id == UserHandle.USER_SYSTEM) {
    106                 viewMessage = mSwitchingToSystemUserMessage;
    107             }
    108 
    109             // If switchingFromSystemUserMessage or switchingToSystemUserMessage is null, fallback
    110             // to system message.
    111             if (viewMessage == null) {
    112                 viewMessage = res.getString(R.string.user_switching_message, mNewUser.name);
    113             }
    114         }
    115         ((TextView) view.findViewById(R.id.message)).setText(viewMessage);
    116         setView(view);
    117     }
    118 
    119     @Override
    120     public void show() {
    121         // Slog.v(TAG, "show called");
    122         super.show();
    123         final View decorView = getWindow().getDecorView();
    124         if (decorView != null) {
    125             decorView.getViewTreeObserver().addOnWindowShownListener(this);
    126         }
    127         // Add a timeout as a safeguard, in case a race in screen on/off causes the window
    128         // callback to never come.
    129         mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG_START_USER),
    130                 WINDOW_SHOWN_TIMEOUT_MS);
    131     }
    132 
    133     @Override
    134     public void onWindowShown() {
    135         // Slog.v(TAG, "onWindowShown called");
    136         startUser();
    137     }
    138 
    139     void startUser() {
    140         synchronized (this) {
    141             if (!mStartedUser) {
    142                 mService.mUserController.startUserInForeground(mUserId);
    143                 dismiss();
    144                 mStartedUser = true;
    145                 final View decorView = getWindow().getDecorView();
    146                 if (decorView != null) {
    147                     decorView.getViewTreeObserver().removeOnWindowShownListener(this);
    148                 }
    149                 mHandler.removeMessages(MSG_START_USER);
    150             }
    151         }
    152     }
    153 
    154     private final Handler mHandler = new Handler() {
    155         @Override
    156         public void handleMessage(Message msg) {
    157             switch (msg.what) {
    158                 case MSG_START_USER:
    159                     startUser();
    160                     break;
    161             }
    162         }
    163     };
    164 }
    165