From c73ce7046757d0ff101a2a2bb3eef5ae56dd47da Mon Sep 17 00:00:00 2001
From: Sunny Goyal <sunnygoyal@google.com>
Date: Sun, 16 Jun 2019 13:50:07 -0700
Subject: [PATCH] Hiding home handle while on home in no-button mode

> Unifying handling home and back button alpha logic

Test: go home, manual
Bug: 134381592
Change-Id: I93a72cc4ac252f2ced22216f14c50b074e9903c8
---
 .../shared/recents/ISystemUiProxy.aidl        |  7 ++++
 .../recents/OverviewProxyService.java         | 32 +++++++++++--------
 .../phone/NavigationBarFragment.java          | 21 ++++++------
 3 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/packages/SystemUI/shared/src/com/android/systemui/shared/recents/ISystemUiProxy.aidl b/packages/SystemUI/shared/src/com/android/systemui/shared/recents/ISystemUiProxy.aidl
index 77bb5141d1e0e..9228b178c76f6 100644
--- a/packages/SystemUI/shared/src/com/android/systemui/shared/recents/ISystemUiProxy.aidl
+++ b/packages/SystemUI/shared/src/com/android/systemui/shared/recents/ISystemUiProxy.aidl
@@ -55,9 +55,16 @@ interface ISystemUiProxy {
     /**
      * Control the {@param alpha} of the back button in the navigation bar and {@param animate} if
      * needed from current value
+     * @deprecated
      */
     void setBackButtonAlpha(float alpha, boolean animate) = 8;
 
+    /**
+     * Control the {@param alpha} of the option nav bar button (back-button in 2 button mode
+     * and home bar in no-button mode) and {@param animate} if needed from current value
+     */
+    void setNavBarButtonAlpha(float alpha, boolean animate) = 19;
+
     /**
      * Proxies motion events from the homescreen UI to the status bar. Only called when
      * swipe down is detected on WORKSPACE. The sender guarantees the following order of events on
diff --git a/packages/SystemUI/src/com/android/systemui/recents/OverviewProxyService.java b/packages/SystemUI/src/com/android/systemui/recents/OverviewProxyService.java
index 88a8b31dc3612..c13c46d1ba4c6 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/OverviewProxyService.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/OverviewProxyService.java
@@ -115,7 +115,7 @@ public class OverviewProxyService implements CallbackController<OverviewProxyLis
     private boolean mBound;
     private boolean mIsEnabled;
     private int mCurrentBoundedUserId = -1;
-    private float mBackButtonAlpha;
+    private float mNavBarButtonAlpha;
     private MotionEvent mStatusBarGestureDownEvent;
     private float mWindowCornerRadius;
     private boolean mSupportsRoundedCornersOnWindows;
@@ -241,21 +241,24 @@ public class OverviewProxyService implements CallbackController<OverviewProxyLis
         }
 
         @Override
-        public void setBackButtonAlpha(float alpha, boolean animate) {
-            if (!verifyCaller("setBackButtonAlpha")) {
+        public void setNavBarButtonAlpha(float alpha, boolean animate) {
+            if (!verifyCaller("setNavBarButtonAlpha")) {
                 return;
             }
             long token = Binder.clearCallingIdentity();
             try {
-                mBackButtonAlpha = alpha;
-                mHandler.post(() -> {
-                    notifyBackButtonAlphaChanged(alpha, animate);
-                });
+                mNavBarButtonAlpha = alpha;
+                mHandler.post(() -> notifyNavBarButtonAlphaChanged(alpha, animate));
             } finally {
                 Binder.restoreCallingIdentity(token);
             }
         }
 
+        @Override
+        public void setBackButtonAlpha(float alpha, boolean animate) {
+            setNavBarButtonAlpha(alpha, animate);
+        }
+
         @Override
         public void onAssistantProgress(@FloatRange(from = 0.0, to = 1.0) float progress) {
             if (!verifyCaller("onAssistantProgress")) {
@@ -465,7 +468,7 @@ public class OverviewProxyService implements CallbackController<OverviewProxyLis
                 .supportsRoundedCornersOnWindows(mContext.getResources());
 
         // Assumes device always starts with back button until launcher tells it that it does not
-        mBackButtonAlpha = 1.0f;
+        mNavBarButtonAlpha = 1.0f;
 
         // Listen for nav bar mode changes
         mNavBarMode = navModeController.addListener(this);
@@ -565,7 +568,7 @@ public class OverviewProxyService implements CallbackController<OverviewProxyLis
     }
 
     public float getBackButtonAlpha() {
-        return mBackButtonAlpha;
+        return mNavBarButtonAlpha;
     }
 
     public void cleanupAfterDeath() {
@@ -637,7 +640,7 @@ public class OverviewProxyService implements CallbackController<OverviewProxyLis
     public void addCallback(OverviewProxyListener listener) {
         mConnectionCallbacks.add(listener);
         listener.onConnectionChanged(mOverviewProxy != null);
-        listener.onBackButtonAlphaChanged(mBackButtonAlpha, false);
+        listener.onNavBarButtonAlphaChanged(mNavBarButtonAlpha, false);
         listener.onSystemUiStateChanged(mSysUiStateFlags);
     }
 
@@ -668,14 +671,14 @@ public class OverviewProxyService implements CallbackController<OverviewProxyLis
         if (mOverviewProxy != null) {
             mOverviewProxy.asBinder().unlinkToDeath(mOverviewServiceDeathRcpt, 0);
             mOverviewProxy = null;
-            notifyBackButtonAlphaChanged(1f, false /* animate */);
+            notifyNavBarButtonAlphaChanged(1f, false /* animate */);
             notifyConnectionChanged();
         }
     }
 
-    private void notifyBackButtonAlphaChanged(float alpha, boolean animate) {
+    private void notifyNavBarButtonAlphaChanged(float alpha, boolean animate) {
         for (int i = mConnectionCallbacks.size() - 1; i >= 0; --i) {
-            mConnectionCallbacks.get(i).onBackButtonAlphaChanged(alpha, animate);
+            mConnectionCallbacks.get(i).onNavBarButtonAlphaChanged(alpha, animate);
         }
     }
 
@@ -766,7 +769,8 @@ public class OverviewProxyService implements CallbackController<OverviewProxyLis
         default void onQuickStepStarted() {}
         default void onOverviewShown(boolean fromHome) {}
         default void onQuickScrubStarted() {}
-        default void onBackButtonAlphaChanged(float alpha, boolean animate) {}
+        /** Notify changes in the nav bar button alpha */
+        default void onNavBarButtonAlphaChanged(float alpha, boolean animate) {}
         default void onSystemUiStateChanged(int sysuiStateFlags) {}
         default void onAssistantProgress(@FloatRange(from = 0.0, to = 1.0) float progress) {}
         default void onAssistantGestureCompletion(float velocity) {}
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarFragment.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarFragment.java
index 79976d0e104de..5708c1b2ed5c0 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarFragment.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarFragment.java
@@ -203,17 +203,16 @@ public class NavigationBarFragment extends LifecycleFragment implements Callback
         }
 
         @Override
-        public void onBackButtonAlphaChanged(float alpha, boolean animate) {
-            final ButtonDispatcher backButton = mNavigationBarView.getBackButton();
-            final boolean useAltBack =
-                    (mNavigationIconHints & StatusBarManager.NAVIGATION_HINT_BACK_ALT) != 0;
-            if (QuickStepContract.isGesturalMode(mNavBarMode) && !useAltBack) {
-                // If property was changed to hide/show back button, going home will trigger
-                // launcher to to change the back button alpha to reflect property change
-                backButton.setVisibility(View.GONE);
-            } else {
-                backButton.setVisibility(alpha > 0 ? View.VISIBLE : View.INVISIBLE);
-                backButton.setAlpha(alpha, animate);
+        public void onNavBarButtonAlphaChanged(float alpha, boolean animate) {
+            ButtonDispatcher buttonDispatcher = null;
+            if (QuickStepContract.isSwipeUpMode(mNavBarMode)) {
+                buttonDispatcher = mNavigationBarView.getBackButton();
+            } else if (QuickStepContract.isGesturalMode(mNavBarMode)) {
+                buttonDispatcher = mNavigationBarView.getHomeHandle();
+            }
+            if (buttonDispatcher != null) {
+                buttonDispatcher.setVisibility(alpha > 0 ? View.VISIBLE : View.INVISIBLE);
+                buttonDispatcher.setAlpha(alpha, animate);
             }
         }
     };