1 /*
2  * Copyright (C) 2017 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.systemui.utils.os;
18 
19 import android.os.Handler;
20 import android.os.Looper;
21 import android.os.Message;
22 
23 import java.util.ArrayList;
24 
25 /**
26  * A handler that allows control over when to dispatch messages and callbacks.
27  *
28  * WARNING: Because most Handler methods are final, the only thing this handler can intercept
29  *          are sending messages and posting runnables, but *NOT* removing messages nor runnables.
30  *          It also *CANNOT* intercept messages posted to the front of queue.
31  */
32 public class FakeHandler extends Handler {
33 
34     private Mode mMode = Mode.IMMEDIATE;
35     private ArrayList<Message> mQueuedMessages = new ArrayList<>();
36 
FakeHandler(Looper looper)37     public FakeHandler(Looper looper) {
38         super(looper);
39     }
40 
41     @Override
sendMessageAtTime(Message msg, long uptimeMillis)42     public boolean sendMessageAtTime(Message msg, long uptimeMillis) {
43         mQueuedMessages.add(msg);
44         if (mMode == Mode.IMMEDIATE) {
45             dispatchQueuedMessages();
46         }
47         return true;
48     }
49 
setMode(Mode mode)50     public void setMode(Mode mode) {
51         mMode = mode;
52     }
53 
54     /**
55      * Dispatch any messages that have been queued on the calling thread.
56      */
dispatchQueuedMessages()57     public void dispatchQueuedMessages() {
58         ArrayList<Message> messages = new ArrayList<>(mQueuedMessages);
59         mQueuedMessages.clear();
60         for (Message msg : messages) {
61             dispatchMessage(msg);
62         }
63     }
64 
65     public enum Mode {
66         /** Messages are dispatched immediately on the calling thread. */
67         IMMEDIATE,
68         /** Messages are queued until {@link #dispatchQueuedMessages()} is called. */
69         QUEUEING,
70     }
71 }
72