Fade back button in and out tied with the overview/shelf (2/3)

Back button changes opacity when moving the shelf during swipe up
between home screen and overview. The alpha changes depending on the
progress of the swipe up animation. When going from app to home and vice
versa, the fade animation does not tie with the swipe up progress. The
fade animation also masks the back button drawable when ime visibility
changes.

Change-Id: I51e42930640ba711e81880b385bb722d7ee8ad33
Fixes: 74581837
Fixes: 76900236
Test: swipe up from home screen to overview

6 files changed, 54 insertions, 16 deletions

diff --git a/quickstep/libs/sysui_shared.jar b/quickstep/libs/sysui_shared.jar
index 5e25fd8bf..53a6ceb4d 100644
--- a/quickstep/libs/sysui_shared.jar
+++ b/quickstep/libs/sysui_shared.jar
diff --git a/quickstep/src/com/android/launcher3/uioverrides/UiFactory.java b/quickstep/src/com/android/launcher3/uioverrides/UiFactory.java
index 3e80d2cb6..b371677f3 100644
--- a/quickstep/src/com/android/launcher3/uioverrides/UiFactory.java
+++ b/quickstep/src/com/android/launcher3/uioverrides/UiFactory.java
@@ -93,7 +93,11 @@ public class UiFactory {
                     TYPE_ALL & ~TYPE_HIDE_BACK_BUTTON) == null;
         }
         OverviewInteractionState.getInstance(launcher)
-                .setBackButtonVisible(!shouldBackButtonBeHidden);
+                .setBackButtonAlpha(shouldBackButtonBeHidden ? 0 : 1, true /* animate */);
+    }
+
+    public static void setBackButtonAlpha(Launcher launcher, float alpha, boolean animate) {
+         OverviewInteractionState.getInstance(launcher).setBackButtonAlpha(alpha,animate);
     }
 
     public static void resetOverview(Launcher launcher) {
diff --git a/quickstep/src/com/android/quickstep/OverviewInteractionState.java b/quickstep/src/com/android/quickstep/OverviewInteractionState.java
index 420406ca5..d60574676 100644
--- a/quickstep/src/com/android/quickstep/OverviewInteractionState.java
+++ b/quickstep/src/com/android/quickstep/OverviewInteractionState.java
@@ -17,7 +17,6 @@ package com.android.quickstep;
 
 import static com.android.systemui.shared.system.NavigationBarCompat.FLAG_DISABLE_QUICK_SCRUB;
 import static com.android.systemui.shared.system.NavigationBarCompat.FLAG_DISABLE_SWIPE_UP;
-import static com.android.systemui.shared.system.NavigationBarCompat.FLAG_HIDE_BACK_BUTTON;
 import static com.android.systemui.shared.system.NavigationBarCompat.FLAG_SHOW_OVERVIEW_BUTTON;
 import static com.android.systemui.shared.system.SettingsCompat.SWIPE_UP_SETTING_NAME;
 
@@ -46,7 +45,6 @@ import java.util.concurrent.ExecutionException;
  *
  *   - FLAG_DISABLE_QUICK_SCRUB
  *   - FLAG_DISABLE_SWIPE_UP
- *   - FLAG_HIDE_BACK_BUTTON
  *   - FLAG_SHOW_OVERVIEW_BUTTON
  *
  * @see com.android.systemui.shared.system.NavigationBarCompat.InteractionType and associated flags.
@@ -81,7 +79,7 @@ public class OverviewInteractionState {
     }
 
     private static final int MSG_SET_PROXY = 200;
-    private static final int MSG_SET_BACK_BUTTON_VISIBLE = 201;
+    private static final int MSG_SET_BACK_BUTTON_ALPHA = 201;
     private static final int MSG_SET_SWIPE_UP_ENABLED = 202;
 
     private final SwipeUpGestureEnabledSettingObserver mSwipeUpSettingObserver;
@@ -92,13 +90,16 @@ public class OverviewInteractionState {
 
     // These are updated on the background thread
     private ISystemUiProxy mISystemUiProxy;
-    private boolean mBackButtonVisible = true;
     private boolean mSwipeUpEnabled = true;
 
     private Runnable mOnSwipeUpSettingChangedListener;
 
     private OverviewInteractionState(Context context) {
         mContext = context;
+
+        // Data posted to the uihandler will be sent to the bghandler. Data is sent to uihandler
+        // because of its high send frequency and data may be very different than the previous value
+        // For example, send back alpha on uihandler to avoid flickering when setting its visibility
         mUiHandler = new Handler(this::handleUiMessage);
         mBgHandler = new Handler(UiThreadHelper.getBackgroundLooper(), this::handleBgMessage);
 
@@ -116,9 +117,9 @@ public class OverviewInteractionState {
         return mSwipeUpEnabled;
     }
 
-    public void setBackButtonVisible(boolean visible) {
-        mUiHandler.removeMessages(MSG_SET_BACK_BUTTON_VISIBLE);
-        mUiHandler.obtainMessage(MSG_SET_BACK_BUTTON_VISIBLE, visible ? 1 : 0, 0)
+    public void setBackButtonAlpha(float alpha, boolean animate) {
+        mUiHandler.removeMessages(MSG_SET_BACK_BUTTON_ALPHA);
+        mUiHandler.obtainMessage(MSG_SET_BACK_BUTTON_ALPHA, animate ? 1 : 0, 0, alpha)
                 .sendToTarget();
     }
 
@@ -127,7 +128,7 @@ public class OverviewInteractionState {
     }
 
     private boolean handleUiMessage(Message msg) {
-        mBgHandler.obtainMessage(msg.what, msg.arg1, msg.arg2).sendToTarget();
+        mBgHandler.obtainMessage(msg.what, msg.arg1, msg.arg2, msg.obj).sendToTarget();
         return true;
     }
 
@@ -136,9 +137,9 @@ public class OverviewInteractionState {
             case MSG_SET_PROXY:
                 mISystemUiProxy = (ISystemUiProxy) msg.obj;
                 break;
-            case MSG_SET_BACK_BUTTON_VISIBLE:
-                mBackButtonVisible = msg.arg1 != 0;
-                break;
+            case MSG_SET_BACK_BUTTON_ALPHA:
+                applyBackButtonAlpha((float) msg.obj, msg.arg1 == 1);
+                return true;
             case MSG_SET_SWIPE_UP_ENABLED:
                 mSwipeUpEnabled = msg.arg1 != 0;
                 resetHomeBounceSeenOnQuickstepEnabledFirstTime();
@@ -162,10 +163,8 @@ public class OverviewInteractionState {
             return;
         }
 
-        int flags;
-        if (mSwipeUpEnabled) {
-            flags = mBackButtonVisible ? 0 : FLAG_HIDE_BACK_BUTTON;
-        } else {
+        int flags = 0;
+        if (!mSwipeUpEnabled) {
             flags = FLAG_DISABLE_SWIPE_UP | FLAG_DISABLE_QUICK_SCRUB | FLAG_SHOW_OVERVIEW_BUTTON;
         }
         try {
@@ -175,6 +174,18 @@ public class OverviewInteractionState {
         }
     }
 
+    @WorkerThread
+    private void applyBackButtonAlpha(float alpha, boolean animate) {
+        if (mISystemUiProxy == null) {
+            return;
+        }
+        try {
+            mISystemUiProxy.setBackButtonAlpha(alpha, animate);
+        } catch (RemoteException e) {
+            Log.w(TAG, "Unable to update overview back button alpha", e);
+        }
+    }
+
     private class SwipeUpGestureEnabledSettingObserver extends ContentObserver {
         private Handler mHandler;
         private ContentResolver mResolver;
diff --git a/src/com/android/launcher3/allapps/AllAppsTransitionController.java b/src/com/android/launcher3/allapps/AllAppsTransitionController.java
index 2c3e3ee7b..b5c821ac2 100644
--- a/src/com/android/launcher3/allapps/AllAppsTransitionController.java
+++ b/src/com/android/launcher3/allapps/AllAppsTransitionController.java
@@ -25,9 +25,11 @@ import com.android.launcher3.LauncherState;
 import com.android.launcher3.LauncherStateManager.AnimationConfig;
 import com.android.launcher3.LauncherStateManager.StateHandler;
 import com.android.launcher3.R;
+import com.android.launcher3.Utilities;
 import com.android.launcher3.anim.AnimationSuccessListener;
 import com.android.launcher3.anim.AnimatorSetBuilder;
 import com.android.launcher3.anim.PropertySetter;
+import com.android.launcher3.uioverrides.UiFactory;
 import com.android.launcher3.util.Themes;
 import com.android.launcher3.views.ScrimView;
 
@@ -182,6 +184,13 @@ public class AllAppsTransitionController implements StateHandler, OnDeviceProfil
         anim.setDuration(config.duration);
         anim.setInterpolator(builder.getInterpolator(ANIM_VERTICAL_PROGRESS, interpolator));
         anim.addListener(getProgressAnimatorListener());
+        if (toState.hideBackButton) {
+            anim.addUpdateListener(animation -> {
+                final float alpha = (float) animation.getAnimatedValue();
+                UiFactory.setBackButtonAlpha(mLauncher, 1 - Utilities.boundToRange(alpha, 0, 1),
+                        false /* animate */);
+            });
+        }
 
         builder.play(anim);
 
diff --git a/src/com/android/launcher3/touch/AbstractStateChangeTouchController.java b/src/com/android/launcher3/touch/AbstractStateChangeTouchController.java
index e29250a5e..8ffa62813 100644
--- a/src/com/android/launcher3/touch/AbstractStateChangeTouchController.java
+++ b/src/com/android/launcher3/touch/AbstractStateChangeTouchController.java
@@ -42,6 +42,7 @@ import com.android.launcher3.Utilities;
 import com.android.launcher3.anim.AnimationSuccessListener;
 import com.android.launcher3.anim.AnimatorPlaybackController;
 import com.android.launcher3.anim.AnimatorSetBuilder;
+import com.android.launcher3.uioverrides.UiFactory;
 import com.android.launcher3.userevent.nano.LauncherLogProto.Action.Direction;
 import com.android.launcher3.userevent.nano.LauncherLogProto.Action.Touch;
 import com.android.launcher3.userevent.nano.LauncherLogProto.ContainerType;
@@ -221,6 +222,8 @@ public abstract class AbstractStateChangeTouchController
             cancelAtomicComponentsController();
         }
         mProgressMultiplier = initCurrentAnimation(animComponents);
+        mCurrentAnimation.getAnimationPlayer().addUpdateListener(animation ->
+                setBackButtonAlphaWithProgress((float) animation.getAnimatedValue()));
         mCurrentAnimation.dispatchOnStart();
         return true;
     }
@@ -279,6 +282,7 @@ public abstract class AbstractStateChangeTouchController
             mAtomicComponentsController.setPlayFraction(fraction - mAtomicComponentsStartProgress);
         }
         maybeUpdateAtomicAnim(mFromState, mToState, fraction);
+        setBackButtonAlphaWithProgress(fraction);
     }
 
     /**
@@ -471,6 +475,14 @@ public abstract class AbstractStateChangeTouchController
         }
     }
 
+    private void setBackButtonAlphaWithProgress(float progress) {
+        if (mFromState.hideBackButton ^ mToState.hideBackButton) {
+            progress = Utilities.boundToRange(progress, 0, 1);
+            final float alpha = mToState.hideBackButton ? 1 - progress : progress;
+            UiFactory.setBackButtonAlpha(mLauncher, alpha, false /* animate */);
+        }
+    }
+
     private void logReachedState(int logAction) {
         // Transition complete. log the action
         mLauncher.getUserEventDispatcher().logStateChangeAction(logAction,
diff --git a/src_ui_overrides/com/android/launcher3/uioverrides/UiFactory.java b/src_ui_overrides/com/android/launcher3/uioverrides/UiFactory.java
index e93dd5a03..db98f9a80 100644
--- a/src_ui_overrides/com/android/launcher3/uioverrides/UiFactory.java
+++ b/src_ui_overrides/com/android/launcher3/uioverrides/UiFactory.java
@@ -56,4 +56,6 @@ public class UiFactory {
     }
 
     public static void prepareToShowOverview(Launcher launcher) { }
+
+    public static void setBackButtonAlpha(Launcher launcher, float alpha, boolean animate) { }
 }