1 /*
2  * Copyright (C) 2011 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.incallui;
18 
19 import android.os.Bundle;
20 import android.support.v4.app.FragmentActivity;
21 
22 /**
23  * A common superclass that keeps track of whether an {@link Activity} has saved its state yet or
24  * not.
25  */
26 public abstract class TransactionSafeFragmentActivity extends FragmentActivity {
27 
28   private boolean isSafeToCommitTransactions;
29 
30   @Override
onCreate(Bundle savedInstanceState)31   protected void onCreate(Bundle savedInstanceState) {
32     super.onCreate(savedInstanceState);
33     isSafeToCommitTransactions = true;
34   }
35 
36   @Override
onStart()37   protected void onStart() {
38     super.onStart();
39     isSafeToCommitTransactions = true;
40   }
41 
42   @Override
onResume()43   protected void onResume() {
44     super.onResume();
45     isSafeToCommitTransactions = true;
46   }
47 
48   @Override
onSaveInstanceState(Bundle outState)49   protected void onSaveInstanceState(Bundle outState) {
50     super.onSaveInstanceState(outState);
51     isSafeToCommitTransactions = false;
52   }
53 
54   /**
55    * Returns true if it is safe to commit {@link FragmentTransaction}s at this time, based on
56    * whether {@link Activity#onSaveInstanceState} has been called or not.
57    *
58    * <p>Make sure that the current activity calls into {@link super.onSaveInstanceState(Bundle
59    * outState)} (if that method is overridden), so the flag is properly set.
60    */
isSafeToCommitTransactions()61   public boolean isSafeToCommitTransactions() {
62     return isSafeToCommitTransactions;
63   }
64 }
65