Merge "Revert "Cancel gestures on launcher destroy"" into tm-qpr-dev
diff --git a/quickstep/src/com/android/launcher3/LauncherLifecycleListener.java b/quickstep/src/com/android/launcher3/LauncherInitListener.java
similarity index 78%
rename from quickstep/src/com/android/launcher3/LauncherLifecycleListener.java
rename to quickstep/src/com/android/launcher3/LauncherInitListener.java
index 82c646d..28bd701 100644
--- a/quickstep/src/com/android/launcher3/LauncherLifecycleListener.java
+++ b/quickstep/src/com/android/launcher3/LauncherInitListener.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022 The Android Open Source Project
+ * Copyright (C) 2018 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,23 +16,19 @@
 package com.android.launcher3;
 
 import android.animation.AnimatorSet;
-import android.annotation.Nullable;
 import android.annotation.TargetApi;
 import android.os.Build;
 import android.os.CancellationSignal;
 import android.view.RemoteAnimationTarget;
 
 import com.android.launcher3.uioverrides.QuickstepLauncher;
-import com.android.quickstep.util.ActivityLifecycleListener;
+import com.android.quickstep.util.ActivityInitListener;
 import com.android.quickstep.util.RemoteAnimationProvider;
 
 import java.util.function.BiPredicate;
 
-/**
- * {@link ActivityLifecycleListener} for the in-launcher recents.
- */
 @TargetApi(Build.VERSION_CODES.P)
-public class LauncherLifecycleListener extends ActivityLifecycleListener<Launcher> {
+public class LauncherInitListener extends ActivityInitListener<Launcher> {
 
     private RemoteAnimationProvider mRemoteAnimationProvider;
 
@@ -40,16 +36,13 @@
      * @param onInitListener a callback made when the activity is initialized. The callback should
      *                       return true to continue receiving callbacks (ie. for if the activity is
      *                       recreated).
-     * @param onDestroyListener a callback made when the activity is destroyed.
      */
-    public LauncherLifecycleListener(
-            @Nullable BiPredicate<Launcher, Boolean> onInitListener,
-            @Nullable Runnable onDestroyListener) {
-        super(onInitListener, onDestroyListener, Launcher.ACTIVITY_TRACKER);
+    public LauncherInitListener(BiPredicate<Launcher, Boolean> onInitListener) {
+        super(onInitListener, Launcher.ACTIVITY_TRACKER);
     }
 
     @Override
-    public boolean handleActivityReady(Launcher launcher, boolean alreadyOnHome) {
+    public boolean handleInit(Launcher launcher, boolean alreadyOnHome) {
         if (mRemoteAnimationProvider != null) {
             QuickstepTransitionManager appTransitionManager =
                     ((QuickstepLauncher) launcher).getAppTransitionManager();
@@ -75,7 +68,7 @@
             }, cancellationSignal);
         }
         launcher.deferOverlayCallbacksUntilNextResumeOrStop();
-        return super.handleActivityReady(launcher, alreadyOnHome);
+        return super.handleInit(launcher, alreadyOnHome);
     }
 
     @Override
diff --git a/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java b/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
index e41841a..3d8ffc4 100644
--- a/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
+++ b/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
@@ -50,7 +50,6 @@
 import static com.android.quickstep.MultiStateCallback.DEBUG_STATES;
 import static com.android.quickstep.util.ActiveGestureErrorDetector.GestureEvent.CANCEL_RECENTS_ANIMATION;
 import static com.android.quickstep.util.ActiveGestureErrorDetector.GestureEvent.EXPECTING_TASK_APPEARED;
-import static com.android.quickstep.util.ActiveGestureErrorDetector.GestureEvent.LAUNCHER_DESTROYED;
 import static com.android.quickstep.util.ActiveGestureErrorDetector.GestureEvent.ON_SETTLED_ON_END_TARGET;
 import static com.android.quickstep.util.VibratorWrapper.OVERVIEW_HAPTIC;
 import static com.android.quickstep.views.RecentsView.UPDATE_SYSUI_FLAGS_THRESHOLD;
@@ -114,7 +113,7 @@
 import com.android.quickstep.RemoteTargetGluer.RemoteTargetHandle;
 import com.android.quickstep.util.ActiveGestureErrorDetector;
 import com.android.quickstep.util.ActiveGestureLog;
-import com.android.quickstep.util.ActivityLifecycleListener;
+import com.android.quickstep.util.ActivityInitListener;
 import com.android.quickstep.util.AnimatorControllerWithResistance;
 import com.android.quickstep.util.InputConsumerProxy;
 import com.android.quickstep.util.InputProxyHandlerFactory;
@@ -160,7 +159,7 @@
 
     protected final BaseActivityInterface<S, T> mActivityInterface;
     protected final InputConsumerProxy mInputConsumerProxy;
-    protected final ActivityLifecycleListener mActivityInitListener;
+    protected final ActivityInitListener mActivityInitListener;
     // Callbacks to be made once the recents animation starts
     private final ArrayList<Runnable> mRecentsAnimationStartCallbacks = new ArrayList<>();
     private final OnScrollChangedListener mOnRecentsScrollListener = this::onRecentsViewScroll;
@@ -330,8 +329,7 @@
             InputConsumerController inputConsumer) {
         super(context, deviceState, gestureState);
         mActivityInterface = gestureState.getActivityInterface();
-        mActivityInitListener = mActivityInterface.createActivityLifecycleListener(
-                this::onActivityInit, this::onActivityDestroy);
+        mActivityInitListener = mActivityInterface.createActivityInitListener(this::onActivityInit);
         mInputConsumerProxy =
                 new InputConsumerProxy(context, /* rotationSupplier = */ () -> {
                     if (mRecentsView == null) {
@@ -522,11 +520,6 @@
         return true;
     }
 
-    private void onActivityDestroy() {
-        ActiveGestureLog.INSTANCE.addLog("Launcher activity destroyed", LAUNCHER_DESTROYED);
-        onGestureCancelled();
-    }
-
     /**
      * Return true if the window should be translated horizontally if the recents view scrolls
      */
diff --git a/quickstep/src/com/android/quickstep/BaseActivityInterface.java b/quickstep/src/com/android/quickstep/BaseActivityInterface.java
index 5523518..274b686 100644
--- a/quickstep/src/com/android/quickstep/BaseActivityInterface.java
+++ b/quickstep/src/com/android/quickstep/BaseActivityInterface.java
@@ -60,7 +60,7 @@
 import com.android.launcher3.util.DisplayController;
 import com.android.launcher3.util.NavigationMode;
 import com.android.launcher3.views.ScrimView;
-import com.android.quickstep.util.ActivityLifecycleListener;
+import com.android.quickstep.util.ActivityInitListener;
 import com.android.quickstep.util.AnimatorControllerWithResistance;
 import com.android.quickstep.views.RecentsView;
 import com.android.systemui.shared.recents.model.ThumbnailData;
@@ -123,17 +123,8 @@
     public abstract AnimationFactory prepareRecentsUI(RecentsAnimationDeviceState deviceState,
             boolean activityVisible, Consumer<AnimatorControllerWithResistance> callback);
 
-    /**
-     * Creates a activity listener for activity initialized and/or destroyed. One or both of these
-     * listeners must be provided.
-     *
-     * @param onInitListener a callback made when the activity is initialized. The callback should
-     *                       return true to continue receiving callbacks (ie. for if the activity is
-     *                       recreated).
-     * @param onDestroyListener a callback made when the activity is destroyed.
-     */
-    public abstract ActivityLifecycleListener createActivityLifecycleListener(
-            @Nullable Predicate<Boolean> onInitListener, @Nullable Runnable onDestroyListener);
+    public abstract ActivityInitListener createActivityInitListener(
+            Predicate<Boolean> onInitListener);
 
     /**
      * Sets a callback to be run when an activity launch happens while launcher is not yet resumed.
diff --git a/quickstep/src/com/android/quickstep/FallbackActivityInterface.java b/quickstep/src/com/android/quickstep/FallbackActivityInterface.java
index a658566..ae9fb0b 100644
--- a/quickstep/src/com/android/quickstep/FallbackActivityInterface.java
+++ b/quickstep/src/com/android/quickstep/FallbackActivityInterface.java
@@ -36,7 +36,7 @@
 import com.android.launcher3.util.DisplayController;
 import com.android.quickstep.GestureState.GestureEndTarget;
 import com.android.quickstep.fallback.RecentsState;
-import com.android.quickstep.util.ActivityLifecycleListener;
+import com.android.quickstep.util.ActivityInitListener;
 import com.android.quickstep.util.AnimatorControllerWithResistance;
 import com.android.quickstep.views.RecentsView;
 
@@ -88,12 +88,10 @@
     }
 
     @Override
-    public ActivityLifecycleListener createActivityLifecycleListener(
-            @Nullable Predicate<Boolean> onInitListener, @Nullable Runnable onDestroyListener) {
-        return new ActivityLifecycleListener<>(
-                (activity, alreadyOnHome) -> onInitListener.test(alreadyOnHome),
-                onDestroyListener,
-                RecentsActivity.ACTIVITY_TRACKER);
+    public ActivityInitListener createActivityInitListener(
+            Predicate<Boolean> onInitListener) {
+        return new ActivityInitListener<>((activity, alreadyOnHome) ->
+                onInitListener.test(alreadyOnHome), RecentsActivity.ACTIVITY_TRACKER);
     }
 
     @Nullable
diff --git a/quickstep/src/com/android/quickstep/LauncherActivityInterface.java b/quickstep/src/com/android/quickstep/LauncherActivityInterface.java
index cb54d2e..9ff9416 100644
--- a/quickstep/src/com/android/quickstep/LauncherActivityInterface.java
+++ b/quickstep/src/com/android/quickstep/LauncherActivityInterface.java
@@ -37,7 +37,7 @@
 import com.android.launcher3.DeviceProfile;
 import com.android.launcher3.Launcher;
 import com.android.launcher3.LauncherAnimUtils;
-import com.android.launcher3.LauncherLifecycleListener;
+import com.android.launcher3.LauncherInitListener;
 import com.android.launcher3.LauncherState;
 import com.android.launcher3.anim.PendingAnimation;
 import com.android.launcher3.statehandlers.DepthController;
@@ -49,7 +49,7 @@
 import com.android.launcher3.util.DisplayController;
 import com.android.launcher3.util.NavigationMode;
 import com.android.quickstep.GestureState.GestureEndTarget;
-import com.android.quickstep.util.ActivityLifecycleListener;
+import com.android.quickstep.util.ActivityInitListener;
 import com.android.quickstep.util.AnimatorControllerWithResistance;
 import com.android.quickstep.util.LayoutUtils;
 import com.android.quickstep.views.RecentsView;
@@ -136,10 +136,9 @@
     }
 
     @Override
-    public ActivityLifecycleListener createActivityLifecycleListener(
-            @Nullable Predicate<Boolean> onInitListener, @Nullable Runnable onDestroyListener) {
-        return new LauncherLifecycleListener((activity, alreadyOnHome) ->
-                onInitListener.test(alreadyOnHome), onDestroyListener);
+    public ActivityInitListener createActivityInitListener(Predicate<Boolean> onInitListener) {
+        return new LauncherInitListener((activity, alreadyOnHome) ->
+                onInitListener.test(alreadyOnHome));
     }
 
     @Override
diff --git a/quickstep/src/com/android/quickstep/util/ActiveGestureErrorDetector.java b/quickstep/src/com/android/quickstep/util/ActiveGestureErrorDetector.java
index 0fdd8b5..60065fb 100644
--- a/quickstep/src/com/android/quickstep/util/ActiveGestureErrorDetector.java
+++ b/quickstep/src/com/android/quickstep/util/ActiveGestureErrorDetector.java
@@ -37,7 +37,7 @@
         ON_SETTLED_ON_END_TARGET, START_RECENTS_ANIMATION, FINISH_RECENTS_ANIMATION,
         CANCEL_RECENTS_ANIMATION, SET_ON_PAGE_TRANSITION_END_CALLBACK, CANCEL_CURRENT_ANIMATION,
         CLEANUP_SCREENSHOT, SCROLLER_ANIMATION_ABORTED, TASK_APPEARED, EXPECTING_TASK_APPEARED,
-        FLAG_USING_OTHER_ACTIVITY_INPUT_CONSUMER, LAUNCHER_DESTROYED,
+        FLAG_USING_OTHER_ACTIVITY_INPUT_CONSUMER,
 
         /**
          * These GestureEvents are specifically associated to state flags that get set in
@@ -162,13 +162,6 @@
                                         + "before/without setting end target to new task",
                                 writer);
                         break;
-                    case LAUNCHER_DESTROYED:
-                        errorDetected |= printErrorIfTrue(
-                                true,
-                                prefix,
-                                /* errorMessage= */ "Launcher destroyed mid-gesture",
-                                writer);
-                        break;
                     case STATE_GESTURE_COMPLETED:
                         errorDetected |= printErrorIfTrue(
                                 !encounteredEvents.contains(GestureEvent.MOTION_UP),
diff --git a/quickstep/src/com/android/quickstep/util/ActivityInitListener.java b/quickstep/src/com/android/quickstep/util/ActivityInitListener.java
new file mode 100644
index 0000000..aeec36f
--- /dev/null
+++ b/quickstep/src/com/android/quickstep/util/ActivityInitListener.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.quickstep.util;
+
+import com.android.launcher3.BaseActivity;
+import com.android.launcher3.util.ActivityTracker;
+import com.android.launcher3.util.ActivityTracker.SchedulerCallback;
+
+import java.util.function.BiPredicate;
+
+public class ActivityInitListener<T extends BaseActivity> implements
+        SchedulerCallback<T> {
+
+    private BiPredicate<T, Boolean> mOnInitListener;
+    private final ActivityTracker<T> mActivityTracker;
+
+    private boolean mIsRegistered = false;
+
+    /**
+     * @param onInitListener a callback made when the activity is initialized. The callback should
+     *                       return true to continue receiving callbacks (ie. for if the activity is
+     *                       recreated).
+     */
+    public ActivityInitListener(BiPredicate<T, Boolean> onInitListener,
+            ActivityTracker<T> tracker) {
+        mOnInitListener = onInitListener;
+        mActivityTracker = tracker;
+    }
+
+    @Override
+    public final boolean init(T activity, boolean alreadyOnHome) {
+        if (!mIsRegistered) {
+            // Don't receive any more updates
+            return false;
+        }
+        return handleInit(activity, alreadyOnHome);
+    }
+
+    protected boolean handleInit(T activity, boolean alreadyOnHome) {
+        return mOnInitListener.test(activity, alreadyOnHome);
+    }
+
+    /**
+     * Registers the activity-created listener. If the activity is already created, then the
+     * callback provided in the constructor will be called synchronously.
+     */
+    public void register() {
+        mIsRegistered = true;
+        mActivityTracker.registerCallback(this);
+    }
+
+    /**
+     * After calling this, we won't {@link #init} even when the activity is ready.
+     */
+    public void unregister() {
+        mActivityTracker.unregisterCallback(this);
+        mIsRegistered = false;
+        mOnInitListener = null;
+    }
+}
diff --git a/quickstep/src/com/android/quickstep/util/ActivityLifecycleListener.java b/quickstep/src/com/android/quickstep/util/ActivityLifecycleListener.java
deleted file mode 100644
index 1edf188..0000000
--- a/quickstep/src/com/android/quickstep/util/ActivityLifecycleListener.java
+++ /dev/null
@@ -1,113 +0,0 @@
-/*
- * Copyright (C) 2022 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.quickstep.util;
-
-import android.util.Log;
-
-import androidx.annotation.Nullable;
-
-import com.android.launcher3.BaseActivity;
-import com.android.launcher3.util.ActivityTracker;
-import com.android.launcher3.util.ActivityTracker.SchedulerCallback;
-
-import java.util.function.BiPredicate;
-
-/**
- * Listener for activity initialized and/or destroyed.
- */
-public class ActivityLifecycleListener<T extends BaseActivity> implements
-        SchedulerCallback<T> {
-
-    private static final String TAG = "ActivityLifecycleListener";
-
-    @Nullable private final BiPredicate<T, Boolean> mOnInitListener;
-    @Nullable private final Runnable mOnDestroyListener;
-    private final ActivityTracker<T> mActivityTracker;
-
-    private boolean mIsRegistered = false;
-
-    /**
-     * One or both of {@code onInitListener} and {@code onInitListener} must be provided, otherwise
-     * the created instance will effectively be a no-op.
-     *
-     * @param onInitListener a callback made when the activity is initialized. The callback should
-     *                       return true to continue receiving callbacks (ie. for if the activity is
-     *                       recreated).
-     * @param onDestroyListener a callback made when the activity is destroyed.
-     */
-    public ActivityLifecycleListener(
-            @Nullable BiPredicate<T, Boolean> onInitListener,
-            @Nullable Runnable onDestroyListener,
-            ActivityTracker<T> tracker) {
-        if (onInitListener == null && onDestroyListener == null) {
-            throw new IllegalArgumentException("Both listeners cannot be null");
-        }
-        mOnInitListener = onInitListener;
-        mOnDestroyListener = onDestroyListener;
-        mActivityTracker = tracker;
-    }
-
-    @Override
-    public final boolean onActivityReady(T activity, boolean alreadyOnHome) {
-        if (!mIsRegistered) {
-            // Don't receive any more updates
-            return false;
-        }
-        return handleActivityReady(activity, alreadyOnHome);
-    }
-
-    protected boolean handleActivityReady(T activity, boolean alreadyOnHome) {
-        if (mOnInitListener == null) {
-            Log.e(TAG, "Cannot handle init: init listener is null", new Exception());
-            return false;
-        }
-        return mOnInitListener.test(activity, alreadyOnHome);
-    }
-
-    @Override
-    public void onActivityDestroyed() {
-        if (mOnDestroyListener == null) {
-            Log.e(TAG, "Cannot clean up: destroy listener is null", new Exception());
-            return;
-        }
-        mOnDestroyListener.run();
-    }
-
-    /**
-     * Registers the activity-created listener. If the activity is already created, then the
-     * callback provided in the constructor will be called synchronously.
-     */
-    public void register() {
-        mIsRegistered = true;
-        mActivityTracker.registerCallback(this, getType());
-    }
-
-    /**
-     * After calling this, we won't call {@link #onActivityReady} even when the activity is ready.
-     */
-    public void unregister() {
-        mActivityTracker.unregisterCallback(this, getType());
-        mIsRegistered = false;
-    }
-
-    private int getType() {
-        return mOnInitListener != null && mOnDestroyListener != null
-                ? ActivityTracker.TYPE_BOTH
-                : (mOnInitListener != null
-                        ? ActivityTracker.TYPE_INIT
-                        : ActivityTracker.TYPE_DESTROY);
-    }
-}
diff --git a/src/com/android/launcher3/dragndrop/BaseItemDragListener.java b/src/com/android/launcher3/dragndrop/BaseItemDragListener.java
index 6d127b3..981e3a6 100644
--- a/src/com/android/launcher3/dragndrop/BaseItemDragListener.java
+++ b/src/com/android/launcher3/dragndrop/BaseItemDragListener.java
@@ -74,7 +74,7 @@
     }
 
     @Override
-    public boolean onActivityReady(Launcher launcher, boolean alreadyOnHome) {
+    public boolean init(Launcher launcher, boolean alreadyOnHome) {
         AbstractFloatingView.closeAllOpenViews(launcher, alreadyOnHome);
         launcher.getStateManager().goToState(NORMAL, alreadyOnHome /* animated */);
         launcher.getDragLayer().setOnDragListener(this);
diff --git a/src/com/android/launcher3/dragndrop/PinItemDragListener.java b/src/com/android/launcher3/dragndrop/PinItemDragListener.java
index fb924c1..af43ae8 100644
--- a/src/com/android/launcher3/dragndrop/PinItemDragListener.java
+++ b/src/com/android/launcher3/dragndrop/PinItemDragListener.java
@@ -72,8 +72,8 @@
     }
 
     @Override
-    public boolean onActivityReady(Launcher launcher, boolean alreadyOnHome) {
-        super.onActivityReady(launcher, alreadyOnHome);
+    public boolean init(Launcher launcher, boolean alreadyOnHome) {
+        super.init(launcher, alreadyOnHome);
         if (!alreadyOnHome) {
             launcher.useFadeOutAnimationForLauncherStart(mCancelSignal);
         }
diff --git a/src/com/android/launcher3/util/ActivityTracker.java b/src/com/android/launcher3/util/ActivityTracker.java
index 5f93a66..7af1a13 100644
--- a/src/com/android/launcher3/util/ActivityTracker.java
+++ b/src/com/android/launcher3/util/ActivityTracker.java
@@ -20,6 +20,8 @@
 import com.android.launcher3.BaseActivity;
 
 import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.concurrent.CopyOnWriteArrayList;
 
 /**
@@ -28,15 +30,8 @@
  */
 public final class ActivityTracker<T extends BaseActivity> {
 
-    public static final int TYPE_INIT = 0;
-    public static final int TYPE_DESTROY = 1;
-    public static final int TYPE_BOTH = 2;
-
     private WeakReference<T> mCurrentActivity = new WeakReference<>(null);
-    private CopyOnWriteArrayList<SchedulerCallback<T>> mActivityReadyCallbacks =
-            new CopyOnWriteArrayList<>();
-    private CopyOnWriteArrayList<SchedulerCallback<T>> mActivityDestroyedCallbacks =
-            new CopyOnWriteArrayList<>();
+    private CopyOnWriteArrayList<SchedulerCallback<T>> mCallbacks = new CopyOnWriteArrayList<>();
 
     @Nullable
     public <R extends T> R getCreatedActivity() {
@@ -47,74 +42,32 @@
         if (mCurrentActivity.get() == activity) {
             mCurrentActivity.clear();
         }
-        for (SchedulerCallback<T> cb : mActivityDestroyedCallbacks) {
-            cb.onActivityDestroyed();
-            unregisterCallback(cb, TYPE_DESTROY);
-        }
     }
 
-    /** Registers an activity create callback. */
+    /**
+     * Call {@link SchedulerCallback#init(BaseActivity, boolean)} when the
+     * activity is ready. If the activity is already created, this is called immediately.
+     *
+     * The tracker maintains a strong ref to the callback, so it is up to the caller to return
+     * {@code false} in the callback OR to unregister the callback explicitly.
+     *
+     * @param callback The callback to call init() on when the activity is ready.
+     */
     public void registerCallback(SchedulerCallback<T> callback) {
-        registerCallback(callback, TYPE_INIT);
-    }
-
-    /**
-     * Call {@link SchedulerCallback#onActivityReady(BaseActivity, boolean)} when the
-     * activity is ready and/or {@link SchedulerCallback#onActivityDestroyed()} when the activity
-     * is destroyed.
-     *
-     * If type is {@link ActivityTracker#TYPE_INIT} TYPE_INIT or
-     * {@link ActivityTracker#TYPE_BOTH} and the activity is already created, this
-     * {@link SchedulerCallback#onActivityReady(BaseActivity, boolean)} is called immediately.
-     *
-     * If type is {@link ActivityTracker#TYPE_DESTROY} or
-     * {@link ActivityTracker#TYPE_BOTH} and the activity is already destroyed,
-     * {@link SchedulerCallback#onActivityDestroyed()} is called immediately.
-     *
-     * The tracker maintains a strong ref to the callbacks, so it is up to the caller to return
-     * {@code false} in {@link SchedulerCallback#onActivityReady(BaseActivity, boolean)} OR to
-     * unregister the callback explicitly.
-     *
-     * @param callback The callback to call init() or cleanUp() on when the activity is ready or
-     *                 destroyed.
-     * @param type whether to use this callback on activity create, destroy or both.
-     */
-    public void registerCallback(SchedulerCallback<T> callback, int type) {
         T activity = mCurrentActivity.get();
-        if (type == TYPE_INIT || type == TYPE_BOTH) {
-            mActivityReadyCallbacks.add(callback);
-            if (activity != null) {
-                if (!callback.onActivityReady(activity, activity.isStarted())) {
-                    unregisterCallback(callback, TYPE_INIT);
-                }
+        mCallbacks.add(callback);
+        if (activity != null) {
+            if (!callback.init(activity, activity.isStarted())) {
+                unregisterCallback(callback);
             }
         }
-        if (type == TYPE_DESTROY || type == TYPE_BOTH) {
-            mActivityDestroyedCallbacks.add(callback);
-            if (activity == null) {
-                callback.onActivityDestroyed();
-                unregisterCallback(callback, TYPE_DESTROY);
-            }
-        }
-    }
-
-    /**
-     * Unregisters a registered activity create callback.
-     */
-    public void unregisterCallback(SchedulerCallback<T> callback) {
-        unregisterCallback(callback, TYPE_INIT);
     }
 
     /**
      * Unregisters a registered callback.
      */
-    public void unregisterCallback(SchedulerCallback<T> callback, int type) {
-        if (type == TYPE_INIT || type == TYPE_BOTH) {
-            mActivityReadyCallbacks.remove(callback);
-        }
-        if (type == TYPE_DESTROY || type == TYPE_BOTH) {
-            mActivityDestroyedCallbacks.remove(callback);
-        }
+    public void unregisterCallback(SchedulerCallback<T> callback) {
+        mCallbacks.remove(callback);
     }
 
     public boolean handleCreate(T activity) {
@@ -128,8 +81,8 @@
 
     private boolean handleIntent(T activity, boolean alreadyOnHome) {
         boolean handled = false;
-        for (SchedulerCallback<T> cb : mActivityReadyCallbacks) {
-            if (!cb.onActivityReady(activity, alreadyOnHome)) {
+        for (SchedulerCallback<T> cb : mCallbacks) {
+            if (!cb.init(activity, alreadyOnHome)) {
                 // Callback doesn't want any more updates
                 unregisterCallback(cb);
             }
@@ -145,11 +98,6 @@
          * @param alreadyOnHome Whether the activity is already started.
          * @return Whether to continue receiving callbacks (i.e. if the activity is recreated).
          */
-        boolean onActivityReady(T activity, boolean alreadyOnHome);
-
-        /**
-         * Called then the activity gets destroyed.
-         */
-        default void onActivityDestroyed() { }
+        boolean init(T activity, boolean alreadyOnHome);
     }
 }