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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 final 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 
     55     public UserSwitchingDialog(ActivityManagerService service, Context context, UserInfo oldUser,
     56             UserInfo newUser, boolean aboveSystem) {
     57         super(context);
     58 
     59         mService = service;
     60         mUserId = newUser.id;
     61 
     62         // Set up the dialog contents
     63         setCancelable(false);
     64         Resources res = getContext().getResources();
     65         // Custom view due to alignment and font size requirements
     66         View view = LayoutInflater.from(getContext()).inflate(R.layout.user_switching_dialog, null);
     67 
     68         String viewMessage;
     69         if (UserManager.isSplitSystemUser() && newUser.id == UserHandle.USER_SYSTEM) {
     70             viewMessage = res.getString(R.string.user_logging_out_message, oldUser.name);
     71         } else {
     72             viewMessage = res.getString(R.string.user_switching_message, newUser.name);
     73         }
     74         ((TextView) view.findViewById(R.id.message)).setText(viewMessage);
     75         setView(view);
     76 
     77         if (aboveSystem) {
     78             getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ERROR);
     79         }
     80         WindowManager.LayoutParams attrs = getWindow().getAttributes();
     81         attrs.privateFlags = WindowManager.LayoutParams.PRIVATE_FLAG_SYSTEM_ERROR |
     82                 WindowManager.LayoutParams.PRIVATE_FLAG_SHOW_FOR_ALL_USERS;
     83         getWindow().setAttributes(attrs);
     84     }
     85 
     86     @Override
     87     public void show() {
     88         // Slog.v(TAG, "show called");
     89         super.show();
     90         final View decorView = getWindow().getDecorView();
     91         if (decorView != null) {
     92             decorView.getViewTreeObserver().addOnWindowShownListener(this);
     93         }
     94         // Add a timeout as a safeguard, in case a race in screen on/off causes the window
     95         // callback to never come.
     96         mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG_START_USER),
     97                 WINDOW_SHOWN_TIMEOUT_MS);
     98     }
     99 
    100     @Override
    101     public void onWindowShown() {
    102         // Slog.v(TAG, "onWindowShown called");
    103         startUser();
    104     }
    105 
    106     void startUser() {
    107         synchronized (this) {
    108             if (!mStartedUser) {
    109                 mService.mUserController.startUserInForeground(mUserId, this);
    110                 mStartedUser = true;
    111                 final View decorView = getWindow().getDecorView();
    112                 if (decorView != null) {
    113                     decorView.getViewTreeObserver().removeOnWindowShownListener(this);
    114                 }
    115                 mHandler.removeMessages(MSG_START_USER);
    116             }
    117         }
    118     }
    119 
    120     private final Handler mHandler = new Handler() {
    121         @Override
    122         public void handleMessage(Message msg) {
    123             switch (msg.what) {
    124                 case MSG_START_USER:
    125                     startUser();
    126                     break;
    127             }
    128         }
    129     };
    130 }
    131