1 /*
2  * Copyright (C) 2021 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.inputmethodservice;
18 
19 import android.annotation.MainThread;
20 import android.annotation.NonNull;
21 import android.annotation.Nullable;
22 import android.content.res.Configuration;
23 import android.content.res.Resources;
24 
25 import com.android.internal.annotations.VisibleForTesting;
26 import com.android.internal.util.Preconditions;
27 
28 /**
29  * Helper class that takes care of Configuration change behavior of {@link InputMethodService}.
30  * Note: this class is public for testing only. Never call any of it's methods for development
31  * of IMEs.
32  * @hide
33  */
34 @VisibleForTesting(visibility = VisibleForTesting.Visibility.PACKAGE)
35 public final class ImsConfigurationTracker {
36 
37     /**
38      * A constant value that represents {@link Configuration} has changed from the last time
39      * {@link InputMethodService#onConfigurationChanged(Configuration)} was called.
40      */
41     private static final int CONFIG_CHANGED = -1;
42 
43     @Nullable
44     private Configuration mLastKnownConfig = null;
45     private int mHandledConfigChanges = 0;
46     private boolean mInitialized = false;
47 
48     /**
49      * Called from {@link InputMethodService.InputMethodImpl
50      * #initializeInternal(IBinder, int, IInputMethodPrivilegedOperations, int)} ()}
51      * @param handledConfigChanges Configuration changes declared handled by IME
52      * {@link android.R.styleable#InputMethod_configChanges}.
53      */
54     @MainThread
onInitialize(int handledConfigChanges)55     public void onInitialize(int handledConfigChanges) {
56         Preconditions.checkState(!mInitialized, "onInitialize can be called only once.");
57         mInitialized = true;
58         mHandledConfigChanges = handledConfigChanges;
59     }
60 
61     /**
62      * Called from {@link InputMethodService.InputMethodImpl#onBindInput()}
63      */
64     @MainThread
onBindInput(@ullable Resources resources)65     public void onBindInput(@Nullable Resources resources) {
66         if (!mInitialized) {
67             return;
68         }
69         if (mLastKnownConfig == null && resources != null) {
70             mLastKnownConfig = new Configuration(resources.getConfiguration());
71         }
72     }
73 
74     /**
75      * Dynamically set handled configChanges.
76      * Note: this method is public for testing only.
77      */
setHandledConfigChanges(int configChanges)78     public void setHandledConfigChanges(int configChanges) {
79         mHandledConfigChanges = configChanges;
80     }
81 
82     /**
83      * Called from {@link InputMethodService.InputMethodImpl#onConfigurationChanged(Configuration)}}
84      */
85     @MainThread
onConfigurationChanged(@onNull Configuration newConfig, @NonNull Runnable resetStateForNewConfigurationRunner)86     public void onConfigurationChanged(@NonNull Configuration newConfig,
87             @NonNull Runnable resetStateForNewConfigurationRunner) {
88         if (!mInitialized) {
89             return;
90         }
91         final int diff = mLastKnownConfig != null
92                 ? mLastKnownConfig.diffPublicOnly(newConfig) : CONFIG_CHANGED;
93         // If the new config is the same as the config this Service is already running with,
94         // then don't bother calling resetStateForNewConfiguration.
95         final int unhandledDiff = (diff & ~mHandledConfigChanges);
96         if (unhandledDiff != 0) {
97             resetStateForNewConfigurationRunner.run();
98         }
99         if (diff != 0) {
100             mLastKnownConfig = new Configuration(newConfig);
101         }
102     }
103 }
104