Merge "Limit existing usages of nav bar button alpha to two button mode" into sc-dev
diff --git a/quickstep/src/com/android/launcher3/BaseQuickstepLauncher.java b/quickstep/src/com/android/launcher3/BaseQuickstepLauncher.java
index 4f706cf..cdfd1a2 100644
--- a/quickstep/src/com/android/launcher3/BaseQuickstepLauncher.java
+++ b/quickstep/src/com/android/launcher3/BaseQuickstepLauncher.java
@@ -21,6 +21,7 @@
 import static com.android.launcher3.LauncherState.NORMAL;
 import static com.android.launcher3.util.DisplayController.DisplayHolder.CHANGE_SIZE;
 import static com.android.launcher3.util.Executors.UI_HELPER_EXECUTOR;
+import static com.android.quickstep.SysUINavigationMode.Mode.TWO_BUTTONS;
 import static com.android.systemui.shared.system.ActivityManagerWrapper.CLOSE_SYSTEM_WINDOWS_REASON_HOME_KEY;
 
 import android.animation.AnimatorSet;
@@ -79,7 +80,7 @@
      * Reusable command for applying the back button alpha on the background thread.
      */
     public static final UiThreadHelper.AsyncCommand SET_BACK_BUTTON_ALPHA =
-            (context, arg1, arg2) -> SystemUiProxy.INSTANCE.get(context).setBackButtonAlpha(
+            (context, arg1, arg2) -> SystemUiProxy.INSTANCE.get(context).setNavBarButtonAlpha(
                     Float.intBitsToFloat(arg1), arg2 != 0);
 
     private OverviewActionsView mActionsView;
@@ -373,8 +374,10 @@
      */
     private void onLauncherStateOrFocusChanged() {
         boolean shouldBackButtonBeHidden = shouldBackButtonBeHidden(getStateManager().getState());
-        UiThreadHelper.setBackButtonAlphaAsync(this, SET_BACK_BUTTON_ALPHA,
-                shouldBackButtonBeHidden ? 0f : 1f, true /* animate */);
+        if (SysUINavigationMode.getMode(this) == TWO_BUTTONS) {
+            UiThreadHelper.setBackButtonAlphaAsync(this, SET_BACK_BUTTON_ALPHA,
+                    shouldBackButtonBeHidden ? 0f : 1f, true /* animate */);
+        }
         if (getDragLayer() != null) {
             getRootView().setDisallowBackGesture(shouldBackButtonBeHidden);
         }
diff --git a/quickstep/src/com/android/launcher3/statehandlers/BackButtonAlphaHandler.java b/quickstep/src/com/android/launcher3/statehandlers/BackButtonAlphaHandler.java
index 13501a4..ce94305 100644
--- a/quickstep/src/com/android/launcher3/statehandlers/BackButtonAlphaHandler.java
+++ b/quickstep/src/com/android/launcher3/statehandlers/BackButtonAlphaHandler.java
@@ -18,6 +18,7 @@
 
 import static com.android.launcher3.anim.Interpolators.LINEAR;
 import static com.android.quickstep.AnimatedFloat.VALUE;
+import static com.android.quickstep.SysUINavigationMode.Mode.TWO_BUTTONS;
 
 import com.android.launcher3.BaseQuickstepLauncher;
 import com.android.launcher3.LauncherState;
@@ -30,7 +31,7 @@
 import com.android.quickstep.SystemUiProxy;
 
 /**
- * State handler for animating back button alpha
+ * State handler for animating back button alpha in two-button nav mode.
  */
 public class BackButtonAlphaHandler implements StateHandler<LauncherState> {
 
@@ -51,14 +52,11 @@
             return;
         }
 
-        if (!SysUINavigationMode.getMode(mLauncher).hasGestures) {
-            // If the nav mode is not gestural, then force back button alpha to be 1
-            UiThreadHelper.setBackButtonAlphaAsync(mLauncher,
-                    BaseQuickstepLauncher.SET_BACK_BUTTON_ALPHA, 1f, true /* animate */);
+        if (SysUINavigationMode.getMode(mLauncher) != TWO_BUTTONS) {
             return;
         }
 
-        mBackAlpha.value = SystemUiProxy.INSTANCE.get(mLauncher).getLastBackButtonAlpha();
+        mBackAlpha.value = SystemUiProxy.INSTANCE.get(mLauncher).getLastNavButtonAlpha();
         animation.setFloat(mBackAlpha, VALUE,
                 mLauncher.shouldBackButtonBeHidden(toState) ? 0 : 1, LINEAR);
     }
diff --git a/quickstep/src/com/android/quickstep/SystemUiProxy.java b/quickstep/src/com/android/quickstep/SystemUiProxy.java
index f25c358..a1cbec7 100644
--- a/quickstep/src/com/android/quickstep/SystemUiProxy.java
+++ b/quickstep/src/com/android/quickstep/SystemUiProxy.java
@@ -50,7 +50,8 @@
 /**
  * Holds the reference to SystemUI.
  */
-public class SystemUiProxy implements ISystemUiProxy {
+public class SystemUiProxy implements ISystemUiProxy,
+        SysUINavigationMode.NavigationModeChangeListener {
     private static final String TAG = SystemUiProxy.class.getSimpleName();
 
     public static final MainThreadInitializedObject<SystemUiProxy> INSTANCE =
@@ -69,14 +70,20 @@
     // Used to dedupe calls to SystemUI
     private int mLastShelfHeight;
     private boolean mLastShelfVisible;
-    private float mLastBackButtonAlpha;
-    private boolean mLastBackButtonAnimate;
+    private float mLastNavButtonAlpha;
+    private boolean mLastNavButtonAnimate;
 
     // TODO(141886704): Find a way to remove this
     private int mLastSystemUiStateFlags;
 
     public SystemUiProxy(Context context) {
-        // Do nothing
+        SysUINavigationMode.INSTANCE.get(context).addModeChangeListener(this);
+    }
+
+    @Override
+    public void onNavigationModeChanged(SysUINavigationMode.Mode newMode) {
+        // Whenever the nav mode changes, force reset the nav button alpha
+        setNavBarButtonAlpha(1f, false);
     }
 
     @Override
@@ -170,28 +177,17 @@
         return null;
     }
 
-    @Override
-    public void setBackButtonAlpha(float alpha, boolean animate) {
-        boolean changed = Float.compare(alpha, mLastBackButtonAlpha) != 0
-                || animate != mLastBackButtonAnimate;
-        if (mSystemUiProxy != null && changed) {
-            mLastBackButtonAlpha = alpha;
-            mLastBackButtonAnimate = animate;
-            try {
-                mSystemUiProxy.setBackButtonAlpha(alpha, animate);
-            } catch (RemoteException e) {
-                Log.w(TAG, "Failed call setBackButtonAlpha", e);
-            }
-        }
-    }
-
-    public float getLastBackButtonAlpha() {
-        return mLastBackButtonAlpha;
+    public float getLastNavButtonAlpha() {
+        return mLastNavButtonAlpha;
     }
 
     @Override
     public void setNavBarButtonAlpha(float alpha, boolean animate) {
-        if (mSystemUiProxy != null) {
+        boolean changed = Float.compare(alpha, mLastNavButtonAlpha) != 0
+                || animate != mLastNavButtonAnimate;
+        if (mSystemUiProxy != null && changed) {
+            mLastNavButtonAlpha = alpha;
+            mLastNavButtonAnimate = animate;
             try {
                 mSystemUiProxy.setNavBarButtonAlpha(alpha, animate);
             } catch (RemoteException e) {