Reorganize taskbar controllers

Organize existing properties as follows:
- TaskbarViewController contains properties affecting TaskbarView (though child icons are still supplied by TaskbarHotseatController)
- TaskbarDragLayerController contains properties related to TaskbarDragLayer itself
- Renamed NavbarButtonUiController to NavbarButtonsViewController, following the pattern of TaskbarViewController and TaskbarDragLayerController
- TaskbarControllers contains the different controllers to make it easier to construct, initialize, destroy, and pass them around
- Removed TaskbarIconController as its responsibilities were moved to more specific controllers

Test: compiles and runs, manually tested
Bug: 187353581
Change-Id: Idccd95d47117101bf9617e5532a5b87635d2b8f6

quickstep/src/com/android/launcher3/taskbar/TaskbarViewController.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.launcher3.taskbar;
+
+import android.view.View;
+
+import com.android.launcher3.util.MultiValueAlpha;
+
+/**
+ * Handles properties/data collection, then passes the results to TaskbarView to render.
+ */
+public class TaskbarViewController {
+
+    public static final int ALPHA_INDEX_HOME = 0;
+    public static final int ALPHA_INDEX_LAUNCHER_STATE = 1;
+    public static final int ALPHA_INDEX_IME = 2;
+
+    private final TaskbarActivityContext mActivity;
+    private final TaskbarView mTaskbarView;
+    private final MultiValueAlpha mTaskbarIconAlpha;
+
+    // Initialized in init.
+    private TaskbarControllers mControllers;
+
+    public TaskbarViewController(TaskbarActivityContext activity, TaskbarView taskbarView) {
+        mActivity = activity;
+        mTaskbarView = taskbarView;
+        mTaskbarIconAlpha = new MultiValueAlpha(mTaskbarView, 3);
+        mTaskbarIconAlpha.setUpdateVisibility(true);
+    }
+
+    public void init(TaskbarControllers controllers) {
+        mControllers = controllers;
+        mTaskbarView.init(new TaskbarViewCallbacks());
+        mTaskbarView.getLayoutParams().height = mActivity.getDeviceProfile().taskbarSize;
+    }
+
+    public boolean areIconsVisible() {
+        return mTaskbarView.areIconsVisible();
+    }
+
+    public MultiValueAlpha getTaskbarIconAlpha() {
+        return mTaskbarIconAlpha;
+    }
+
+    /**
+     * Should be called when the IME visibility changes, so we can make Taskbar not steal touches.
+     */
+    public void setImeIsVisible(boolean isImeVisible) {
+        mTaskbarView.setTouchesEnabled(!isImeVisible);
+    }
+
+    /**
+     * Sets OnClickListener and OnLongClickListener for the given view.
+     */
+    public void setClickAndLongClickListenersForIcon(View icon) {
+        mTaskbarView.setClickAndLongClickListenersForIcon(icon);
+    }
+
+    /**
+     * Callbacks for {@link TaskbarView} to interact with its controller.
+     */
+    public class TaskbarViewCallbacks {
+        public View.OnClickListener getOnClickListener() {
+            return mActivity::onTaskbarIconClicked;
+        }
+
+        public View.OnLongClickListener getOnLongClickListener() {
+            return mControllers.taskbarDragController::startDragOnLongClick;
+        }
+    }
+}