Animate taskbar background alpha and visibility alpha

Setup codepath to animate the Taskbar when going to and from Launcher,
primarily by listening for pause/resume signals but also hints from
gesture nav and AppToOverviewAnimationProvider.

Additionally, add TaskbarStateHandler to listen for Launcher state
changes if Taskbar is enabled. Combined, the end behavior is:

- Background alpha is 0 when Launcher is resumed, and 1 when Launcher
  is paused (we can make this animation more interesting later).
- Taskbar is always visible when Launcher is paused, otherwise its
  visibility is determined by multiple factors: LauncherState and
  whether the IME is showing.

Bug: 171917176
Change-Id: I7856fc979931c9d12d714dee11d179fd1b5a6968

3 files changed, 13 insertions, 3 deletions

diff --git a/src/com/android/launcher3/LauncherState.java b/src/com/android/launcher3/LauncherState.java
index 79476fc536..f9a1ded355 100644
--- a/src/com/android/launcher3/LauncherState.java
+++ b/src/com/android/launcher3/LauncherState.java
@@ -57,6 +57,7 @@ public abstract class LauncherState implements BaseState<LauncherState> {
     public static final int ALL_APPS_CONTENT = 1 << 4;
     public static final int VERTICAL_SWIPE_INDICATOR = 1 << 5;
     public static final int OVERVIEW_BUTTONS = 1 << 6;
+    public static final int TASKBAR = 1 << 7;
 
     /** Mask of all the items that are contained in the apps view. */
     public static final int APPS_VIEW_ITEM_MASK =
@@ -186,7 +187,7 @@ public abstract class LauncherState implements BaseState<LauncherState> {
     }
 
     public int getVisibleElements(Launcher launcher) {
-        int flags = HOTSEAT_ICONS | VERTICAL_SWIPE_INDICATOR;
+        int flags = HOTSEAT_ICONS | VERTICAL_SWIPE_INDICATOR | TASKBAR;
         if (!FeatureFlags.ENABLE_DEVICE_SEARCH.get()
                 && !launcher.getDeviceProfile().isVerticalBarLayout()) {
             flags |= HOTSEAT_SEARCH_BOX;
diff --git a/src/com/android/launcher3/states/SpringLoadedState.java b/src/com/android/launcher3/states/SpringLoadedState.java
index 45172b56ef..44bcc34588 100644
--- a/src/com/android/launcher3/states/SpringLoadedState.java
+++ b/src/com/android/launcher3/states/SpringLoadedState.java
@@ -90,4 +90,9 @@ public class SpringLoadedState extends LauncherState {
     public float getWorkspaceScrimAlpha(Launcher launcher) {
         return 0.3f;
     }
+
+    @Override
+    public int getVisibleElements(Launcher launcher) {
+        return super.getVisibleElements(launcher) & ~TASKBAR;
+    }
 }
diff --git a/src/com/android/launcher3/states/StateAnimationConfig.java b/src/com/android/launcher3/states/StateAnimationConfig.java
index 8b7217709f..ec949ebffd 100644
--- a/src/com/android/launcher3/states/StateAnimationConfig.java
+++ b/src/com/android/launcher3/states/StateAnimationConfig.java
@@ -37,7 +37,8 @@ public class StateAnimationConfig {
             PLAY_ATOMIC_OVERVIEW_SCALE,
             PLAY_ATOMIC_OVERVIEW_PEEK,
             SKIP_OVERVIEW,
-            SKIP_DEPTH_CONTROLLER
+            SKIP_DEPTH_CONTROLLER,
+            SKIP_TASKBAR,
     })
     @Retention(RetentionPolicy.SOURCE)
     public @interface AnimationFlags {}
@@ -46,6 +47,7 @@ public class StateAnimationConfig {
     public static final int PLAY_ATOMIC_OVERVIEW_PEEK = 1 << 2;
     public static final int SKIP_OVERVIEW = 1 << 3;
     public static final int SKIP_DEPTH_CONTROLLER = 1 << 4;
+    public static final int SKIP_TASKBAR = 1 << 5;
 
     public long duration;
     public boolean userControlled;
@@ -72,6 +74,7 @@ public class StateAnimationConfig {
             ANIM_OVERVIEW_MODAL,
             ANIM_DEPTH,
             ANIM_OVERVIEW_ACTIONS_FADE,
+            ANIM_TASKBAR_FADE,
     })
     @Retention(RetentionPolicy.SOURCE)
     public @interface AnimType {}
@@ -91,8 +94,9 @@ public class StateAnimationConfig {
     public static final int ANIM_OVERVIEW_MODAL = 13;
     public static final int ANIM_DEPTH = 14;
     public static final int ANIM_OVERVIEW_ACTIONS_FADE = 15;
+    public static final int ANIM_TASKBAR_FADE = 16;
 
-    private static final int ANIM_TYPES_COUNT = 16;
+    private static final int ANIM_TYPES_COUNT = 17;
 
     protected final Interpolator[] mInterpolators = new Interpolator[ANIM_TYPES_COUNT];