Removing back-button alpha animation code

Back button is only animation in 2-button UI which is not supported anymore

Bug: 246006580
Test: Presubmit
Change-Id: I7385b07272e44c1f9f0488c158e1b4ee67060120
diff --git a/quickstep/src/com/android/launcher3/statehandlers/BackButtonAlphaHandler.java b/quickstep/src/com/android/launcher3/statehandlers/BackButtonAlphaHandler.java
deleted file mode 100644
index d33859b..0000000
--- a/quickstep/src/com/android/launcher3/statehandlers/BackButtonAlphaHandler.java
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * 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.
- * 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.launcher3.statehandlers;
-
-import static com.android.launcher3.anim.Interpolators.LINEAR;
-import static com.android.launcher3.util.NavigationMode.TWO_BUTTONS;
-import static com.android.quickstep.AnimatedFloat.VALUE;
-
-import com.android.launcher3.LauncherState;
-import com.android.launcher3.anim.PendingAnimation;
-import com.android.launcher3.statemanager.StateManager.StateHandler;
-import com.android.launcher3.states.StateAnimationConfig;
-import com.android.launcher3.uioverrides.QuickstepLauncher;
-import com.android.launcher3.util.DisplayController;
-import com.android.launcher3.util.UiThreadHelper;
-import com.android.quickstep.AnimatedFloat;
-import com.android.quickstep.SystemUiProxy;
-
-/**
- * State handler for animating back button alpha in two-button nav mode.
- */
-public class BackButtonAlphaHandler implements StateHandler<LauncherState> {
-
-    private final QuickstepLauncher mLauncher;
-    private final AnimatedFloat mBackAlpha = new AnimatedFloat(this::updateBackAlpha);
-
-    public BackButtonAlphaHandler(QuickstepLauncher launcher) {
-        mLauncher = launcher;
-    }
-
-    @Override
-    public void setState(LauncherState state) { }
-
-    @Override
-    public void setStateWithAnimation(LauncherState toState, StateAnimationConfig config,
-            PendingAnimation animation) {
-        if (DisplayController.getNavigationMode(mLauncher) != TWO_BUTTONS) {
-            return;
-        }
-
-        mBackAlpha.value = SystemUiProxy.INSTANCE.get(mLauncher).getLastNavButtonAlpha();
-        animation.setFloat(mBackAlpha, VALUE,
-                mLauncher.shouldBackButtonBeHidden(toState) ? 0 : 1, LINEAR);
-    }
-
-    private void updateBackAlpha() {
-        UiThreadHelper.setBackButtonAlphaAsync(mLauncher,
-                QuickstepLauncher.SET_BACK_BUTTON_ALPHA, mBackAlpha.value, false /* animate */);
-    }
-}
diff --git a/quickstep/src/com/android/launcher3/uioverrides/QuickstepLauncher.java b/quickstep/src/com/android/launcher3/uioverrides/QuickstepLauncher.java
index 0a99204..585dec5 100644
--- a/quickstep/src/com/android/launcher3/uioverrides/QuickstepLauncher.java
+++ b/quickstep/src/com/android/launcher3/uioverrides/QuickstepLauncher.java
@@ -17,14 +17,11 @@
 
 import static android.view.accessibility.AccessibilityEvent.TYPE_VIEW_FOCUSED;
 
-import static com.android.launcher3.AbstractFloatingView.TYPE_ALL;
-import static com.android.launcher3.AbstractFloatingView.TYPE_HIDE_BACK_BUTTON;
 import static com.android.launcher3.LauncherSettings.Favorites.CONTAINER_HOTSEAT;
 import static com.android.launcher3.LauncherSettings.Favorites.ITEM_TYPE_APPLICATION;
 import static com.android.launcher3.LauncherSettings.Favorites.ITEM_TYPE_DEEP_SHORTCUT;
 import static com.android.launcher3.LauncherSettings.Favorites.ITEM_TYPE_SHORTCUT;
 import static com.android.launcher3.LauncherState.ALL_APPS;
-import static com.android.launcher3.LauncherState.FLAG_HIDE_BACK_BUTTON;
 import static com.android.launcher3.LauncherState.NORMAL;
 import static com.android.launcher3.LauncherState.NO_OFFSET;
 import static com.android.launcher3.LauncherState.OVERVIEW;
@@ -47,7 +44,6 @@
 import static com.android.launcher3.util.DisplayController.CHANGE_NAVIGATION_MODE;
 import static com.android.launcher3.util.Executors.THREAD_POOL_EXECUTOR;
 import static com.android.launcher3.util.Executors.UI_HELPER_EXECUTOR;
-import static com.android.launcher3.util.NavigationMode.TWO_BUTTONS;
 import static com.android.systemui.shared.system.ActivityManagerWrapper.CLOSE_SYSTEM_WINDOWS_REASON_HOME_KEY;
 
 import android.animation.AnimatorSet;
@@ -72,7 +68,6 @@
 
 import androidx.annotation.Nullable;
 
-import com.android.launcher3.AbstractFloatingView;
 import com.android.launcher3.DeviceProfile;
 import com.android.launcher3.Launcher;
 import com.android.launcher3.LauncherSettings.Favorites;
@@ -96,7 +91,6 @@
 import com.android.launcher3.popup.SystemShortcut;
 import com.android.launcher3.proxy.ProxyActivityStarter;
 import com.android.launcher3.proxy.StartActivityParams;
-import com.android.launcher3.statehandlers.BackButtonAlphaHandler;
 import com.android.launcher3.statehandlers.DepthController;
 import com.android.launcher3.statemanager.StateManager.AtomicAnimationFactory;
 import com.android.launcher3.statemanager.StateManager.StateHandler;
@@ -171,12 +165,6 @@
      */
     public static final AsyncCommand SET_SHELF_HEIGHT = (context, arg1, arg2) ->
             SystemUiProxy.INSTANCE.get(context).setShelfHeight(arg1 != 0, arg2);
-    /**
-     * Reusable command for applying the back button alpha on the background thread.
-     */
-    public static final AsyncCommand SET_BACK_BUTTON_ALPHA =
-            (context, arg1, arg2) -> SystemUiProxy.INSTANCE.get(context).setNavBarButtonAlpha(
-                    Float.intBitsToFloat(arg1), arg2 != 0);
 
     private FixedContainerItems mAllAppsPredictions;
     private HotseatPredictionController mHotseatPredictionController;
@@ -299,11 +287,6 @@
 
     @Override
     protected void onActivityFlagsChanged(int changeBits) {
-        if ((changeBits
-                & (ACTIVITY_STATE_WINDOW_FOCUSED | ACTIVITY_STATE_TRANSITION_ACTIVE)) != 0) {
-            onLauncherStateOrFocusChanged();
-        }
-
         if ((changeBits & ACTIVITY_STATE_STARTED) != 0) {
             mDepthController.setActivityStarted(isStarted());
         }
@@ -729,7 +712,6 @@
         super.collectStateHandlers(out);
         out.add(getDepthController());
         out.add(new RecentsViewStateController(this));
-        out.add(new BackButtonAlphaHandler(this));
     }
 
     public DepthController getDepthController() {
@@ -788,39 +770,6 @@
     }
 
     @Override
-    public void onDragLayerHierarchyChanged() {
-        onLauncherStateOrFocusChanged();
-    }
-
-    public boolean shouldBackButtonBeHidden(LauncherState toState) {
-        NavigationMode mode = DisplayController.getNavigationMode(this);
-        boolean shouldBackButtonBeHidden = mode.hasGestures
-                && toState.hasFlag(FLAG_HIDE_BACK_BUTTON)
-                && hasWindowFocus()
-                && (getActivityFlags() & ACTIVITY_STATE_TRANSITION_ACTIVE) == 0;
-        if (shouldBackButtonBeHidden) {
-            // Show the back button if there is a floating view visible.
-            shouldBackButtonBeHidden = AbstractFloatingView.getTopOpenViewWithType(this,
-                    TYPE_ALL & ~TYPE_HIDE_BACK_BUTTON) == null;
-        }
-        return shouldBackButtonBeHidden;
-    }
-
-    /**
-     * Sets the back button visibility based on the current state/window focus.
-     */
-    private void onLauncherStateOrFocusChanged() {
-        boolean shouldBackButtonBeHidden = shouldBackButtonBeHidden(getStateManager().getState());
-        if (DisplayController.getNavigationMode(this) == TWO_BUTTONS) {
-            UiThreadHelper.setBackButtonAlphaAsync(this, SET_BACK_BUTTON_ALPHA,
-                    shouldBackButtonBeHidden ? 0f : 1f, true /* animate */);
-        }
-        if (getDragLayer() != null) {
-            getRootView().setDisallowBackGesture(shouldBackButtonBeHidden);
-        }
-    }
-
-    @Override
     public void finishBindingItems(IntSet pagesBoundFirst) {
         super.finishBindingItems(pagesBoundFirst);
         // Instantiate and initialize WellbeingModel now that its loading won't interfere with
diff --git a/quickstep/src/com/android/quickstep/SystemUiProxy.java b/quickstep/src/com/android/quickstep/SystemUiProxy.java
index 8e9ff2f..b57f2ce 100644
--- a/quickstep/src/com/android/quickstep/SystemUiProxy.java
+++ b/quickstep/src/com/android/quickstep/SystemUiProxy.java
@@ -17,7 +17,6 @@
 
 import static android.app.ActivityManager.RECENT_IGNORE_UNAVAILABLE;
 
-import static com.android.launcher3.util.DisplayController.CHANGE_NAVIGATION_MODE;
 import static com.android.launcher3.util.Executors.MAIN_EXECUTOR;
 
 import android.app.ActivityManager;
@@ -43,8 +42,6 @@
 import android.view.SurfaceControl;
 import android.window.IOnBackInvokedCallback;
 
-import com.android.launcher3.util.DisplayController;
-import com.android.launcher3.util.DisplayController.Info;
 import com.android.launcher3.util.MainThreadInitializedObject;
 import com.android.launcher3.util.SplitConfigurationOptions;
 import com.android.systemui.shared.recents.ISystemUiProxy;
@@ -72,7 +69,7 @@
 /**
  * Holds the reference to SystemUI.
  */
-public class SystemUiProxy implements ISystemUiProxy, DisplayController.DisplayInfoChangeListener {
+public class SystemUiProxy implements ISystemUiProxy {
     private static final String TAG = SystemUiProxy.class.getSimpleName();
 
     public static final MainThreadInitializedObject<SystemUiProxy> INSTANCE =
@@ -106,29 +103,16 @@
     // Used to dedupe calls to SystemUI
     private int mLastShelfHeight;
     private boolean mLastShelfVisible;
-    private float mLastNavButtonAlpha;
-    private boolean mLastNavButtonAnimate;
-    private boolean mHasNavButtonAlphaBeenSet = false;
-    private Runnable mPendingSetNavButtonAlpha = null;
     private Context mContext;
 
     // TODO(141886704): Find a way to remove this
     private int mLastSystemUiStateFlags;
 
     public SystemUiProxy(Context context) {
-        DisplayController.INSTANCE.get(context).addChangeListener(this);
         mContext = context;
     }
 
     @Override
-    public void onDisplayInfoChanged(Context context, Info info, int flags) {
-        if ((flags & CHANGE_NAVIGATION_MODE) != 0) {
-            // Whenever the nav mode changes, force reset the nav button alpha
-            setNavBarButtonAlpha(1f, false);
-        }
-    }
-
-    @Override
     public void onBackPressed() {
         if (mSystemUiProxy != null) {
             try {
@@ -205,11 +189,6 @@
         if (mBackAnimation != null && mBackToLauncherCallback != null) {
             setBackToLauncherCallback(mBackToLauncherCallback);
         }
-
-        if (mPendingSetNavButtonAlpha != null) {
-            mPendingSetNavButtonAlpha.run();
-            mPendingSetNavButtonAlpha = null;
-        }
     }
 
     public void clearProxy() {
@@ -272,31 +251,6 @@
         }
     }
 
-    public float getLastNavButtonAlpha() {
-        return mLastNavButtonAlpha;
-    }
-
-    @Override
-    public void setNavBarButtonAlpha(float alpha, boolean animate) {
-        boolean changed = Float.compare(alpha, mLastNavButtonAlpha) != 0
-                || animate != mLastNavButtonAnimate
-                || !mHasNavButtonAlphaBeenSet;
-        if (changed) {
-            if (mSystemUiProxy == null) {
-                mPendingSetNavButtonAlpha = () -> setNavBarButtonAlpha(alpha, animate);
-            } else {
-                mLastNavButtonAlpha = alpha;
-                mLastNavButtonAnimate = animate;
-                mHasNavButtonAlphaBeenSet = true;
-                try {
-                    mSystemUiProxy.setNavBarButtonAlpha(alpha, animate);
-                } catch (RemoteException e) {
-                    Log.w(TAG, "Failed call setNavBarButtonAlpha", e);
-                }
-            }
-        }
-    }
-
     @Override
     public void onStatusBarMotionEvent(MotionEvent event) {
         if (mSystemUiProxy != null) {
@@ -895,8 +849,7 @@
         if (mRecentTasks != null
                 && mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_PC)) {
             try {
-                return new ArrayList<ActivityManager.RunningTaskInfo>(
-                        Arrays.asList(mRecentTasks.getRunningTasks(numTasks)));
+                return new ArrayList<>(Arrays.asList(mRecentTasks.getRunningTasks(numTasks)));
             } catch (RemoteException e) {
                 Log.w(TAG, "Failed call getRunningTasks", e);
             }
diff --git a/src/com/android/launcher3/AbstractFloatingView.java b/src/com/android/launcher3/AbstractFloatingView.java
index 21dbc5f..5ee6fce 100644
--- a/src/com/android/launcher3/AbstractFloatingView.java
+++ b/src/com/android/launcher3/AbstractFloatingView.java
@@ -109,10 +109,6 @@
             | TYPE_ALL_APPS_EDU | TYPE_ICON_SURFACE | TYPE_WIDGETS_EDUCATION_DIALOG
             | TYPE_TASKBAR_EDUCATION_DIALOG | TYPE_TASKBAR_ALL_APPS | TYPE_OPTIONS_POPUP_DIALOG;
 
-    // Usually we show the back button when a floating view is open. Instead, hide for these types.
-    public static final int TYPE_HIDE_BACK_BUTTON = TYPE_ON_BOARD_POPUP | TYPE_DISCOVERY_BOUNCE
-            | TYPE_SNACKBAR | TYPE_WIDGET_RESIZE_FRAME | TYPE_LISTENER;
-
     public static final int TYPE_ACCESSIBLE = TYPE_ALL & ~TYPE_DISCOVERY_BOUNCE & ~TYPE_LISTENER
             & ~TYPE_ALL_APPS_EDU;
 
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index 4312c3d..8e978d1 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -1123,6 +1123,7 @@
                         .log(getAllAppsEntryEvent().get());
             }
         }
+        updateDisallowBack();
     }
 
     /**
@@ -3133,7 +3134,18 @@
 
     public void useFadeOutAnimationForLauncherStart(CancellationSignal signal) { }
 
-    public void onDragLayerHierarchyChanged() { }
+    public void onDragLayerHierarchyChanged() {
+        updateDisallowBack();
+    }
+
+    private void updateDisallowBack() {
+        LauncherRootView rv = getRootView();
+        if (rv != null) {
+            boolean disableBack = getStateManager().getState() == NORMAL
+                    && AbstractFloatingView.getTopOpenView(this) == null;
+            rv.setDisallowBackGesture(disableBack);
+        }
+    }
 
     @Override
     public void returnToHomescreen() {
diff --git a/src/com/android/launcher3/LauncherState.java b/src/com/android/launcher3/LauncherState.java
index c3b5392..31a7d18 100644
--- a/src/com/android/launcher3/LauncherState.java
+++ b/src/com/android/launcher3/LauncherState.java
@@ -71,17 +71,14 @@
     public static final int FLAG_WORKSPACE_ICONS_CAN_BE_DRAGGED = BaseState.getFlag(2);
     // Flag to indicate that workspace should draw page background
     public static final int FLAG_WORKSPACE_HAS_BACKGROUNDS = BaseState.getFlag(3);
-    // True if the back button should be hidden when in this state (assuming no floating views are
-    // open, launcher has window focus, etc).
-    public static final int FLAG_HIDE_BACK_BUTTON = BaseState.getFlag(4);
     // Flag to indicate if the state would have scrim over sysui region: statu sbar and nav bar
-    public static final int FLAG_HAS_SYS_UI_SCRIM = BaseState.getFlag(5);
+    public static final int FLAG_HAS_SYS_UI_SCRIM = BaseState.getFlag(4);
     // Flag to inticate that all popups should be closed when this state is enabled.
-    public static final int FLAG_CLOSE_POPUPS = BaseState.getFlag(6);
-    public static final int FLAG_OVERVIEW_UI = BaseState.getFlag(7);
+    public static final int FLAG_CLOSE_POPUPS = BaseState.getFlag(5);
+    public static final int FLAG_OVERVIEW_UI = BaseState.getFlag(6);
 
     // Flag indicating that hotseat and its contents are not accessible.
-    public static final int FLAG_HOTSEAT_INACCESSIBLE = BaseState.getFlag(8);
+    public static final int FLAG_HOTSEAT_INACCESSIBLE = BaseState.getFlag(7);
 
 
     public static final float NO_OFFSET = 0;
@@ -110,8 +107,7 @@
      */
     public static final LauncherState NORMAL = new LauncherState(NORMAL_STATE_ORDINAL,
             LAUNCHER_STATE_HOME,
-            FLAG_DISABLE_RESTORE | FLAG_WORKSPACE_ICONS_CAN_BE_DRAGGED | FLAG_HIDE_BACK_BUTTON |
-                    FLAG_HAS_SYS_UI_SCRIM) {
+            FLAG_DISABLE_RESTORE | FLAG_WORKSPACE_ICONS_CAN_BE_DRAGGED | FLAG_HAS_SYS_UI_SCRIM) {
         @Override
         public int getTransitionDuration(Context context, boolean isToState) {
             // Arbitrary duration, when going to NORMAL we use the state we're coming from instead.
diff --git a/src/com/android/launcher3/states/SpringLoadedState.java b/src/com/android/launcher3/states/SpringLoadedState.java
index b63715c..3286afb 100644
--- a/src/com/android/launcher3/states/SpringLoadedState.java
+++ b/src/com/android/launcher3/states/SpringLoadedState.java
@@ -31,8 +31,7 @@
 
     private static final int STATE_FLAGS = FLAG_MULTI_PAGE
             | FLAG_WORKSPACE_INACCESSIBLE | FLAG_DISABLE_RESTORE
-            | FLAG_WORKSPACE_ICONS_CAN_BE_DRAGGED | FLAG_WORKSPACE_HAS_BACKGROUNDS
-            | FLAG_HIDE_BACK_BUTTON;
+            | FLAG_WORKSPACE_ICONS_CAN_BE_DRAGGED | FLAG_WORKSPACE_HAS_BACKGROUNDS;
 
     public SpringLoadedState(int id) {
         super(id, LAUNCHER_STATE_HOME, STATE_FLAGS);
diff --git a/src/com/android/launcher3/util/UiThreadHelper.java b/src/com/android/launcher3/util/UiThreadHelper.java
index b952090..013479f 100644
--- a/src/com/android/launcher3/util/UiThreadHelper.java
+++ b/src/com/android/launcher3/util/UiThreadHelper.java
@@ -97,11 +97,6 @@
                 .sendToTarget();
     }
 
-    public static void setBackButtonAlphaAsync(Context context, AsyncCommand command, float alpha,
-            boolean animate) {
-        runAsyncCommand(context, command, Float.floatToIntBits(alpha), animate ? 1 : 0);
-    }
-
     public static void runAsyncCommand(Context context, AsyncCommand command, int arg1, int arg2) {
         Message.obtain(HANDLER.get(context), MSG_RUN_COMMAND, arg1, arg2, command).sendToTarget();
     }