Rotate back button drawable when IME present.

Currently rotation for IME rotates the whole view, including the background.

Fix: 266874111
Test: manual.
Change-Id: Iea310c99d0714d98ce534a0170316a0fb351f57d
diff --git a/quickstep/src/com/android/launcher3/taskbar/NavbarButtonsViewController.java b/quickstep/src/com/android/launcher3/taskbar/NavbarButtonsViewController.java
index 9cec881..728c91f 100644
--- a/quickstep/src/com/android/launcher3/taskbar/NavbarButtonsViewController.java
+++ b/quickstep/src/com/android/launcher3/taskbar/NavbarButtonsViewController.java
@@ -20,6 +20,7 @@
 import static android.view.ViewTreeObserver.InternalInsetsInfo.TOUCHABLE_INSETS_REGION;
 import static android.view.WindowManager.LayoutParams.TYPE_NAVIGATION_BAR_PANEL;
 
+import static com.android.launcher3.LauncherAnimUtils.ROTATION_DRAWABLE_PERCENT;
 import static com.android.launcher3.LauncherAnimUtils.VIEW_TRANSLATE_X;
 import static com.android.launcher3.Utilities.getDescendantCoordRelativeToAncestor;
 import static com.android.launcher3.taskbar.LauncherTaskbarUIController.SYSUI_SURFACE_PROGRESS_INDEX;
@@ -60,6 +61,7 @@
 import android.graphics.Region.Op;
 import android.graphics.drawable.AnimatedVectorDrawable;
 import android.graphics.drawable.PaintDrawable;
+import android.graphics.drawable.RotateDrawable;
 import android.inputmethodservice.InputMethodService;
 import android.os.Handler;
 import android.util.Property;
@@ -172,10 +174,10 @@
     // Initialized in init.
     private TaskbarControllers mControllers;
     private boolean mIsImeRenderingNavButtons;
-    private View mA11yButton;
+    private ImageView mA11yButton;
     private int mSysuiStateFlags;
-    private View mBackButton;
-    private View mHomeButton;
+    private ImageView mBackButton;
+    private ImageView mHomeButton;
     private MultiValueAlpha mBackButtonAlpha;
     private MultiValueAlpha mHomeButtonAlpha;
     private FloatingRotationButton mFloatingRotationButton;
@@ -186,7 +188,7 @@
     private final ViewTreeObserver.OnComputeInternalInsetsListener mSeparateWindowInsetsComputer =
             this::onComputeInsetsForSeparateWindow;
     private final RecentsHitboxExtender mHitboxExtender = new RecentsHitboxExtender();
-    private View mRecentsButton;
+    private ImageView mRecentsButton;
 
     public NavbarButtonsViewController(TaskbarActivityContext context, FrameLayout navButtonsView) {
         mContext = context;
@@ -353,13 +355,13 @@
                     return (flags & FLAG_DISABLE_BACK) == 0
                             && ((flags & FLAG_KEYGUARD_VISIBLE) == 0 || showingOnKeyguard);
                 }));
-        boolean isRtl = Utilities.isRtl(mContext.getResources());
         mPropertyHolders.add(new StatePropertyHolder(mBackButton,
-                flags -> (flags & FLAG_IME_VISIBLE) != 0 && !mContext.isNavBarKidsModeActive(),
-                View.ROTATION, isRtl ? 90 : -90, 0));
+                flags -> (flags & FLAG_IME_VISIBLE) != 0,
+                ROTATION_DRAWABLE_PERCENT, 1f, 0f));
         // Translate back button to be at end/start of other buttons for keyguard
         int navButtonSize = mContext.getResources().getDimensionPixelSize(
                 R.dimen.taskbar_nav_buttons_size);
+        boolean isRtl = Utilities.isRtl(mContext.getResources());
         mPropertyHolders.add(new StatePropertyHolder(
                 mBackButton, flags -> (flags & FLAG_ONLY_BACK_FOR_BOUNCER_VISIBLE) != 0
                         || (flags & FLAG_KEYGUARD_VISIBLE) != 0,
@@ -734,13 +736,18 @@
             int paddingBottom = paddingTop;
 
             // Update icons
-            ((ImageView) mBackButton).setImageDrawable(
-                    mBackButton.getContext().getDrawable(R.drawable.ic_sysbar_back_kids));
-            ((ImageView) mBackButton).setScaleType(ImageView.ScaleType.FIT_CENTER);
+            final RotateDrawable rotateDrawable = new RotateDrawable();
+            rotateDrawable.setDrawable(mContext.getDrawable(R.drawable.ic_sysbar_back_kids));
+            rotateDrawable.setFromDegrees(0f);
+            rotateDrawable.setToDegrees(-90f);
+            mBackButton.setImageDrawable(rotateDrawable);
+            mBackButton.setScaleType(ImageView.ScaleType.FIT_CENTER);
             mBackButton.setPadding(paddingleft, paddingTop, paddingRight, paddingBottom);
-            ((ImageView) mHomeButton).setImageDrawable(
+            mBackButton.setScaleX(Utilities.isRtl(mContext.getResources()) ? -1f : 1f);
+
+            mHomeButton.setImageDrawable(
                     mHomeButton.getContext().getDrawable(R.drawable.ic_sysbar_home_kids));
-            ((ImageView) mHomeButton).setScaleType(ImageView.ScaleType.FIT_CENTER);
+            mHomeButton.setScaleType(ImageView.ScaleType.FIT_CENTER);
             mHomeButton.setPadding(paddingleft, paddingTop, paddingRight, paddingBottom);
 
             // Home button layout
@@ -781,6 +788,12 @@
 
             mHomeButton.setOnLongClickListener(null);
         } else if (mContext.isThreeButtonNav()) {
+            final RotateDrawable rotateDrawable = new RotateDrawable();
+            rotateDrawable.setDrawable(mContext.getDrawable(R.drawable.ic_sysbar_back));
+            rotateDrawable.setFromDegrees(0f);
+            rotateDrawable.setToDegrees(Utilities.isRtl(mContext.getResources()) ? 90f : -90f);
+            mBackButton.setImageDrawable(rotateDrawable);
+
             // Setup normal 3 button
             // Add spacing after the end of the last nav button
             FrameLayout.LayoutParams navButtonParams =
diff --git a/src/com/android/launcher3/LauncherAnimUtils.java b/src/com/android/launcher3/LauncherAnimUtils.java
index 4e80d41..c20f323 100644
--- a/src/com/android/launcher3/LauncherAnimUtils.java
+++ b/src/com/android/launcher3/LauncherAnimUtils.java
@@ -26,6 +26,7 @@
 import android.util.IntProperty;
 import android.view.View;
 import android.view.ViewGroup.LayoutParams;
+import android.widget.ImageView;
 import android.widget.TextView;
 
 import com.android.launcher3.util.MultiScalePropertyFactory;
@@ -200,6 +201,23 @@
                 }
             };
 
+    public static final FloatProperty<ImageView> ROTATION_DRAWABLE_PERCENT =
+            new FloatProperty<ImageView>("drawableRotationPercent") {
+                // RotateDrawable linearly interpolates the rotation degrees between fromDegrees
+                // and toDegrees using the drawable level as a percent of its MAX_LEVEL.
+                private static final int MAX_LEVEL = 10000;
+
+                @Override
+                public void setValue(ImageView view, float percent) {
+                    view.setImageLevel((int) (percent * MAX_LEVEL));
+                }
+
+                @Override
+                public Float get(ImageView view) {
+                    return view.getDrawable().getLevel() / (float) MAX_LEVEL;
+                }
+            };
+
     /**
      * Utility method to create an {@link AnimatorListener} which executes a callback on animation
      * cancel.