1 /* 2 * Copyright (C) 2022 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.app; 18 19 import android.annotation.CallbackExecutor; 20 import android.annotation.NonNull; 21 import android.os.IBinder; 22 import android.os.RemoteException; 23 import android.util.ArrayMap; 24 25 import java.util.concurrent.Executor; 26 27 /** Handles screen capture callbacks. 28 * @hide 29 **/ 30 public class ScreenCaptureCallbackHandler { 31 32 private final IBinder mActivityToken; 33 private final ScreenCaptureObserver mObserver; 34 private final ArrayMap<Activity.ScreenCaptureCallback, ScreenCaptureRegistration> 35 mScreenCaptureRegistrations = new ArrayMap<>(); 36 ScreenCaptureCallbackHandler(@onNull IBinder activityToken)37 public ScreenCaptureCallbackHandler(@NonNull IBinder activityToken) { 38 mActivityToken = activityToken; 39 mObserver = new ScreenCaptureObserver(mScreenCaptureRegistrations); 40 } 41 42 private static class ScreenCaptureRegistration { 43 Executor mExecutor; 44 Activity.ScreenCaptureCallback mCallback; 45 ScreenCaptureRegistration(Executor executor, Activity.ScreenCaptureCallback callback)46 ScreenCaptureRegistration(Executor executor, Activity.ScreenCaptureCallback callback) { 47 this.mExecutor = executor; 48 this.mCallback = callback; 49 } 50 } 51 52 private static class ScreenCaptureObserver extends IScreenCaptureObserver.Stub { 53 ArrayMap<Activity.ScreenCaptureCallback, ScreenCaptureRegistration> mRegistrations; 54 ScreenCaptureObserver( ArrayMap<Activity.ScreenCaptureCallback, ScreenCaptureRegistration> registrations)55 ScreenCaptureObserver( 56 ArrayMap<Activity.ScreenCaptureCallback, ScreenCaptureRegistration> 57 registrations) { 58 this.mRegistrations = registrations; 59 } 60 61 @Override onScreenCaptured()62 public void onScreenCaptured() { 63 for (ScreenCaptureRegistration registration : mRegistrations.values()) { 64 registration.mExecutor.execute( 65 () -> { 66 registration.mCallback.onScreenCaptured(); 67 }); 68 } 69 } 70 } 71 72 /** 73 * Start monitoring for screen captures of the activity, the callback will be triggered whenever 74 * a screen capture is attempted. This callback will be executed on the thread of the passed 75 * {@code executor}. If the window is FLAG_SECURE, the callback will not be triggered. 76 */ registerScreenCaptureCallback( @onNull @allbackExecutor Executor executor, @NonNull Activity.ScreenCaptureCallback callback)77 public void registerScreenCaptureCallback( 78 @NonNull @CallbackExecutor Executor executor, 79 @NonNull Activity.ScreenCaptureCallback callback) { 80 ScreenCaptureRegistration registration = 81 new ScreenCaptureRegistration(executor, callback); 82 synchronized (mScreenCaptureRegistrations) { 83 if (mScreenCaptureRegistrations.containsKey(callback)) { 84 throw new IllegalStateException( 85 "Capture observer already registered with the activity"); 86 } 87 mScreenCaptureRegistrations.put(callback, registration); 88 // register with system server only once. 89 if (mScreenCaptureRegistrations.size() == 1) { 90 try { 91 ActivityTaskManager.getService() 92 .registerScreenCaptureObserver(mActivityToken, mObserver); 93 } catch (RemoteException e) { 94 e.rethrowFromSystemServer(); 95 } 96 } 97 } 98 } 99 /** Stop monitoring for screen captures of the activity */ unregisterScreenCaptureCallback(@onNull Activity.ScreenCaptureCallback callback)100 public void unregisterScreenCaptureCallback(@NonNull Activity.ScreenCaptureCallback callback) { 101 synchronized (mScreenCaptureRegistrations) { 102 if (!mScreenCaptureRegistrations.containsKey(callback)) { 103 throw new IllegalStateException( 104 "Capture observer not registered with the activity"); 105 } 106 mScreenCaptureRegistrations.remove(callback); 107 // unregister only if no more registrations are left 108 if (mScreenCaptureRegistrations.size() == 0) { 109 try { 110 ActivityTaskManager.getService().unregisterScreenCaptureObserver(mActivityToken, 111 mObserver); 112 } catch (RemoteException e) { 113 e.rethrowFromSystemServer(); 114 } 115 } 116 } 117 } 118 } 119