1 /*
2  * Copyright (C) 2018 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 android.view;
18 
19 import android.content.Context;
20 import android.os.Build;
21 
22 import java.util.ArrayList;
23 import java.util.List;
24 
25 /**
26  * Compatibility processor for InputEvents that allows events to be adjusted before and
27  * after it is sent to the application.
28  *
29  * {@hide}
30  */
31 public class InputEventCompatProcessor {
32 
33     protected Context mContext;
34     protected int mTargetSdkVersion;
35 
36     /** List of events to be used to return the processed events */
37     private List<InputEvent> mProcessedEvents;
38 
InputEventCompatProcessor(Context context)39     public InputEventCompatProcessor(Context context) {
40         mContext = context;
41         mTargetSdkVersion = context.getApplicationInfo().targetSdkVersion;
42         mProcessedEvents = new ArrayList<>();
43     }
44 
45     /**
46      * Processes the InputEvent for compatibility before it is sent to the app, allowing for the
47      * generation of more than one event if necessary.
48      *
49      * @param e The InputEvent to process
50      * @return The list of adjusted events, or null if no adjustments are needed. Do not keep a
51      *         reference to the output as the list is reused.
52      */
processInputEventForCompatibility(InputEvent e)53     public List<InputEvent> processInputEventForCompatibility(InputEvent e) {
54         if (mTargetSdkVersion < Build.VERSION_CODES.M && e instanceof MotionEvent) {
55             mProcessedEvents.clear();
56             MotionEvent motion = (MotionEvent) e;
57             final int mask =
58                     MotionEvent.BUTTON_STYLUS_PRIMARY | MotionEvent.BUTTON_STYLUS_SECONDARY;
59             final int buttonState = motion.getButtonState();
60             final int compatButtonState = (buttonState & mask) >> 4;
61             if (compatButtonState != 0) {
62                 motion.setButtonState(buttonState | compatButtonState);
63             }
64             mProcessedEvents.add(motion);
65             return mProcessedEvents;
66         }
67         return null;
68     }
69 
70     /**
71      * Processes the InputEvent for compatibility before it is finished by calling
72      * InputEventReceiver#finishInputEvent().
73      *
74      * @param e The InputEvent to process
75      * @return The InputEvent to finish, or null if it should not be finished
76      */
processInputEventBeforeFinish(InputEvent e)77     public InputEvent processInputEventBeforeFinish(InputEvent e) {
78         // No changes needed
79         return e;
80     }
81 }
82