NavigationBarMenuView.java

/*
 * Copyright (C) 2020 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.google.android.material.navigation;

import com.google.android.material.R;

import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.ColorStateList;
import android.graphics.drawable.Drawable;
import androidx.appcompat.content.res.AppCompatResources;
import androidx.appcompat.view.menu.MenuBuilder;
import androidx.appcompat.view.menu.MenuItemImpl;
import androidx.appcompat.view.menu.MenuView;
import android.util.SparseArray;
import android.util.TypedValue;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.accessibility.AccessibilityNodeInfo;
import androidx.annotation.Dimension;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.Px;
import androidx.annotation.RestrictTo;
import androidx.annotation.StyleRes;
import androidx.core.util.Pools;
import androidx.core.view.ViewCompat;
import androidx.core.view.accessibility.AccessibilityNodeInfoCompat;
import androidx.core.view.accessibility.AccessibilityNodeInfoCompat.CollectionInfoCompat;
import androidx.transition.AutoTransition;
import androidx.transition.TransitionManager;
import androidx.transition.TransitionSet;
import com.google.android.material.animation.AnimationUtils;
import com.google.android.material.badge.BadgeDrawable;
import com.google.android.material.internal.TextScale;
import com.google.android.material.motion.MotionUtils;
import com.google.android.material.shape.MaterialShapeDrawable;
import com.google.android.material.shape.ShapeAppearanceModel;
import java.util.HashSet;

/**
 * Provides a view that will be use to render a menu view inside a {@link NavigationBarView}.
 *
 * @hide
 */
@RestrictTo(LIBRARY_GROUP)
public abstract class NavigationBarMenuView extends ViewGroup implements MenuView {
  private static final int ITEM_POOL_SIZE = 5;
  private static final int NO_PADDING = -1;

  private static final int[] CHECKED_STATE_SET = {android.R.attr.state_checked};
  private static final int[] DISABLED_STATE_SET = {-android.R.attr.state_enabled};

  @NonNull private final TransitionSet set;
  @NonNull private final OnClickListener onClickListener;
  private final Pools.Pool<NavigationBarItemView> itemPool =
      new Pools.SynchronizedPool<>(ITEM_POOL_SIZE);

  @NonNull
  private final SparseArray<OnTouchListener> onTouchListeners = new SparseArray<>(ITEM_POOL_SIZE);

  @NavigationBarView.LabelVisibility private int labelVisibilityMode;

  @Nullable private NavigationBarItemView[] buttons;
  private int selectedItemId = 0;
  private int selectedItemPosition = 0;

  @Nullable private ColorStateList itemIconTint;
  @Dimension private int itemIconSize;
  private ColorStateList itemTextColorFromUser;
  @Nullable private final ColorStateList itemTextColorDefault;
  @StyleRes private int itemTextAppearanceInactive;
  @StyleRes private int itemTextAppearanceActive;
  private Drawable itemBackground;
  private int itemBackgroundRes;
  @NonNull private final SparseArray<BadgeDrawable> badgeDrawables =
      new SparseArray<>(ITEM_POOL_SIZE);
  private int itemPaddingTop = NO_PADDING;
  private int itemPaddingBottom = NO_PADDING;
  private boolean itemActiveIndicatorEnabled;
  private int itemActiveIndicatorWidth;
  private int itemActiveIndicatorHeight;
  private int itemActiveIndicatorMarginHorizontal;
  private ShapeAppearanceModel itemActiveIndicatorShapeAppearance;
  private boolean itemActiveIndicatorResizeable = false;
  private ColorStateList itemActiveIndicatorColor;

  private NavigationBarPresenter presenter;
  private MenuBuilder menu;

  public NavigationBarMenuView(@NonNull Context context) {
    super(context);

    itemTextColorDefault = createDefaultColorStateList(android.R.attr.textColorSecondary);

    set = new AutoTransition();
    set.setOrdering(TransitionSet.ORDERING_TOGETHER);
    set.setDuration(
        MotionUtils.resolveThemeDuration(
            getContext(),
            R.attr.motionDurationLong1,
            getResources().getInteger(R.integer.material_motion_duration_long_1)));
    set.setInterpolator(
        MotionUtils.resolveThemeInterpolator(
            getContext(),
            R.attr.motionEasingStandard,
            AnimationUtils.FAST_OUT_SLOW_IN_INTERPOLATOR));
    set.addTransition(new TextScale());

    onClickListener =
        new OnClickListener() {
          @Override
          public void onClick(View v) {
            final NavigationBarItemView itemView = (NavigationBarItemView) v;
            MenuItem item = itemView.getItemData();
            if (!menu.performItemAction(item, presenter, 0)) {
              item.setChecked(true);
            }
          }
        };

    ViewCompat.setImportantForAccessibility(this, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES);
  }

  @Override
  public void initialize(@NonNull MenuBuilder menu) {
    this.menu = menu;
  }

  @Override
  public int getWindowAnimations() {
    return 0;
  }

  @Override
  public void onInitializeAccessibilityNodeInfo(@NonNull AccessibilityNodeInfo info) {
    super.onInitializeAccessibilityNodeInfo(info);
    AccessibilityNodeInfoCompat infoCompat = AccessibilityNodeInfoCompat.wrap(info);
    infoCompat.setCollectionInfo(
        CollectionInfoCompat.obtain(
            /* rowCount= */ 1,
            /* columnCount= */ menu.getVisibleItems().size(),
            /* hierarchical= */ false,
            /* selectionMode = */ CollectionInfoCompat.SELECTION_MODE_SINGLE));
  }

  /**
   * Sets the tint which is applied to the menu items' icons.
   *
   * @param tint the tint to apply
   */
  public void setIconTintList(@Nullable ColorStateList tint) {
    itemIconTint = tint;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setIconTintList(tint);
      }
    }
  }

  /**
   * Returns the tint which is applied for the menu item labels.
   *
   * @return the ColorStateList that is used to tint menu items' icons
   */
  @Nullable
  public ColorStateList getIconTintList() {
    return itemIconTint;
  }

  /**
   * Sets the size to provide for the menu item icons.
   *
   * <p>For best image resolution, use an icon with the same size set in this method.
   *
   * @param iconSize the size to provide for the menu item icons in pixels
   */
  public void setItemIconSize(@Dimension int iconSize) {
    this.itemIconSize = iconSize;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setIconSize(iconSize);
      }
    }
  }

  /** Returns the size in pixels provided for the menu item icons. */
  @Dimension
  public int getItemIconSize() {
    return itemIconSize;
  }

  /**
   * Sets the text color to be used for the menu item labels.
   *
   * @param color the ColorStateList used for menu item labels
   */
  public void setItemTextColor(@Nullable ColorStateList color) {
    itemTextColorFromUser = color;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setTextColor(color);
      }
    }
  }

  /**
   * Returns the text color used for menu item labels.
   *
   * @return the ColorStateList used for menu items labels
   */
  @Nullable
  public ColorStateList getItemTextColor() {
    return itemTextColorFromUser;
  }

  /**
   * Sets the text appearance to be used for inactive menu item labels.
   *
   * @param textAppearanceRes the text appearance ID used for inactive menu item labels
   */
  public void setItemTextAppearanceInactive(@StyleRes int textAppearanceRes) {
    this.itemTextAppearanceInactive = textAppearanceRes;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setTextAppearanceInactive(textAppearanceRes);
        // Set the text color if the user has set it, since itemTextColorFromUser takes precedence
        // over a color set in the text appearance.
        if (itemTextColorFromUser != null) {
          item.setTextColor(itemTextColorFromUser);
        }
      }
    }
  }

  /**
   * Returns the text appearance used for inactive menu item labels.
   *
   * @return the text appearance ID used for inactive menu item labels
   */
  @StyleRes
  public int getItemTextAppearanceInactive() {
    return itemTextAppearanceInactive;
  }

  /**
   * Sets the text appearance to be used for the active menu item label.
   *
   * @param textAppearanceRes the text appearance ID used for the active menu item label
   */
  public void setItemTextAppearanceActive(@StyleRes int textAppearanceRes) {
    this.itemTextAppearanceActive = textAppearanceRes;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setTextAppearanceActive(textAppearanceRes);
        // Set the text color if the user has set it, since itemTextColorFromUser takes precedence
        // over a color set in the text appearance.
        if (itemTextColorFromUser != null) {
          item.setTextColor(itemTextColorFromUser);
        }
      }
    }
  }

  /**
   * Returns the text appearance used for the active menu item label.
   *
   * @return the text appearance ID used for the active menu item label
   */
  @StyleRes
  public int getItemTextAppearanceActive() {
    return itemTextAppearanceActive;
  }

  /**
   * Sets the resource ID to be used for item backgrounds.
   *
   * @param background the resource ID of the background
   */
  public void setItemBackgroundRes(int background) {
    itemBackgroundRes = background;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setItemBackground(background);
      }
    }
  }

  /**
   * Get the distance from the top of an item's icon/active indicator to the top of the navigation
   * bar item.
   */
  @Px
  public int getItemPaddingTop() {
    return itemPaddingTop;
  }

  /**
   * Set the distance from the top of an items icon/active indicator to the top of the navigation
   * bar item.
   */
  public void setItemPaddingTop(@Px int paddingTop) {
    itemPaddingTop = paddingTop;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setItemPaddingTop(paddingTop);
      }
    }
  }

  /**
   * Get the distance from the bottom of an item's label to the bottom of the navigation bar item.
   */
  @Px
  public int getItemPaddingBottom() {
    return itemPaddingBottom;
  }

  /**
   * Set the distance from the bottom of an item's label to the bottom of the navigation bar item.
   */
  public void setItemPaddingBottom(@Px int paddingBottom) {
    itemPaddingBottom = paddingBottom;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setItemPaddingBottom(paddingBottom);
      }
    }
  }

  /**
   * Returns whether or not an active indicator is enabled for the navigation bar.
   *
   * @return true if the active indicator is enabled.
   */
  public boolean getItemActiveIndicatorEnabled() {
    return itemActiveIndicatorEnabled;
  }

  /**
   * Set whether or not an active indicator is enabled for the navigation bar.
   *
   * @param enabled true if an active indicator should be shown.
   */
  public void setItemActiveIndicatorEnabled(boolean enabled) {
    this.itemActiveIndicatorEnabled = enabled;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setActiveIndicatorEnabled(enabled);
      }
    }
  }

  /**
   * Get the width of the selected item's active indicator.
   *
   * @return The width, in pixels, of the active indicator.
   */
  @Px
  public int getItemActiveIndicatorWidth() {
    return itemActiveIndicatorWidth;
  }

  /**
   * Set the width to be used for the selected item's active indicator.
   *
   * @param width The width, in pixels, of the active indicator.
   */
  public void setItemActiveIndicatorWidth(@Px int width) {
    this.itemActiveIndicatorWidth = width;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setActiveIndicatorWidth(width);
      }
    }
  }

  /**
   * Get the height of the selected item's active indicator.
   *
   * @return The height, in pixels, of the active indicator.
   */
  @Px
  public int getItemActiveIndicatorHeight() {
    return itemActiveIndicatorHeight;
  }

  /**
   * Set the height to be used for the selected item's active indicator.
   *
   * @param height The height, in pixels, of the active indicator.
   */
  public void setItemActiveIndicatorHeight(@Px int height) {
    this.itemActiveIndicatorHeight = height;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setActiveIndicatorHeight(height);
      }
    }
  }

  /**
   * Get the margin that will be maintained at the start and end of the active indicator away from
   * the edges of its parent container.
   *
   * @return The horizontal margin, in pixels.
   */
  @Px
  public int getItemActiveIndicatorMarginHorizontal() {
    return itemActiveIndicatorMarginHorizontal;
  }

  /**
   * Set the horizontal margin that will be maintained at the start and end of the active indicator,
   * making sure the indicator remains the given distance from the edge of its parent container.
   *
   * @param marginHorizontal The horizontal margin, in pixels.
   */
  public void setItemActiveIndicatorMarginHorizontal(@Px int marginHorizontal) {
    itemActiveIndicatorMarginHorizontal = marginHorizontal;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setActiveIndicatorMarginHorizontal(marginHorizontal);
      }
    }
  }

  /**
   * Get the {@link ShapeAppearanceModel} of the active indicator drawable.
   *
   * @return The {@link ShapeAppearanceModel} of the active indicator drawable.
   */
  @Nullable
  public ShapeAppearanceModel getItemActiveIndicatorShapeAppearance() {
    return itemActiveIndicatorShapeAppearance;
  }

  /**
   * Set the {@link ShapeAppearanceModel} of the active indicator drawable.
   *
   * @param shapeAppearance The {@link ShapeAppearanceModel} of the active indicator drawable.
   */
  public void setItemActiveIndicatorShapeAppearance(
      @Nullable ShapeAppearanceModel shapeAppearance) {
    this.itemActiveIndicatorShapeAppearance = shapeAppearance;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setActiveIndicatorDrawable(createItemActiveIndicatorDrawable());
      }
    }
  }

  /**
   * Get whether the active indicator can be resized.
   */
  protected boolean isItemActiveIndicatorResizeable() {
    return this.itemActiveIndicatorResizeable;
  }

  /**
   * Set whether the active indicator can be resized. If true, the indicator will automatically
   * change size in response to label visibility modes.
   */
  protected void setItemActiveIndicatorResizeable(boolean resizeable) {
    this.itemActiveIndicatorResizeable = resizeable;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setActiveIndicatorResizeable(resizeable);
      }
    }
  }

  /**
   * Get the color of the active indicator drawable.
   *
   * @return A {@link ColorStateList} used as the color of the active indicator.
   */
  @Nullable
  public ColorStateList getItemActiveIndicatorColor() {
    return itemActiveIndicatorColor;
  }

  /**
   * Set the {@link ColorStateList} of the active indicator drawable.
   *
   * @param csl The {@link ColorStateList} used as the color of the active indicator.
   */
  public void setItemActiveIndicatorColor(@Nullable ColorStateList csl) {
    this.itemActiveIndicatorColor = csl;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setActiveIndicatorDrawable(createItemActiveIndicatorDrawable());
      }
    }
  }

  /**
   * Create a drawable using the {@code itemActiveIndicatorShapeAppearance} and {@code
   * itemActiveIndicatorColor} to be used as an item's active indicator.
   *
   * <p>This method is called once per menu item so each item has a unique drawable instance which
   * can be manipulated/animated independently.
   *
   * @return A drawable to be used as a menu item's active indicator.
   */
  @Nullable
  private Drawable createItemActiveIndicatorDrawable() {
    if (itemActiveIndicatorShapeAppearance != null && itemActiveIndicatorColor != null) {
      MaterialShapeDrawable drawable =
          new MaterialShapeDrawable(itemActiveIndicatorShapeAppearance);
      drawable.setFillColor(itemActiveIndicatorColor);
      return drawable;
    }

    return null;
  }

  /**
   * Returns the resource ID for the background of the menu items.
   *
   * @return the resource ID for the background
   * @deprecated Use {@link #getItemBackground()} instead.
   */
  @Deprecated
  public int getItemBackgroundRes() {
    return itemBackgroundRes;
  }

  /**
   * Sets the drawable to be used for item backgrounds.
   *
   * @param background the drawable of the background
   */
  public void setItemBackground(@Nullable Drawable background) {
    itemBackground = background;
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        item.setItemBackground(background);
      }
    }
  }

  /**
   * Returns the drawable for the background of the menu items.
   *
   * @return the drawable for the background
   */
  @Nullable
  public Drawable getItemBackground() {
    if (buttons != null && buttons.length > 0) {
      // Return button background instead of itemBackground if possible, so that the correct
      // drawable is returned if the background is set via #setItemBackgroundRes.
      return buttons[0].getBackground();
    } else {
      return itemBackground;
    }
  }

  /**
   * Sets the navigation items' label visibility mode.
   *
   * <p>The label is either always shown, never shown, or only shown when activated. Also supports
   * "auto" mode, which uses the item count to determine whether to show or hide the label.
   *
   * @param labelVisibilityMode mode which decides whether or not the label should be shown. Can be
   *     one of {@link NavigationBarView#LABEL_VISIBILITY_AUTO}, {@link
   *     NavigationBarView#LABEL_VISIBILITY_SELECTED}, {@link
   *     NavigationBarView#LABEL_VISIBILITY_LABELED}, or {@link
   *     NavigationBarView#LABEL_VISIBILITY_UNLABELED}
   * @see #getLabelVisibilityMode()
   */
  public void setLabelVisibilityMode(@NavigationBarView.LabelVisibility int labelVisibilityMode) {
    this.labelVisibilityMode = labelVisibilityMode;
  }

  /**
   * Returns the current label visibility mode.
   *
   * @see #setLabelVisibilityMode(int)
   */
  public int getLabelVisibilityMode() {
    return labelVisibilityMode;
  }

  /**
   * Sets an {@link android.view.View.OnTouchListener} for the item view associated with the
   * provided {@code menuItemId}.
   */
  @SuppressLint("ClickableViewAccessibility")
  public void setItemOnTouchListener(int menuItemId, @Nullable OnTouchListener onTouchListener) {
    if (onTouchListener == null) {
      onTouchListeners.remove(menuItemId);
    } else {
      onTouchListeners.put(menuItemId, onTouchListener);
    }
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        if (item.getItemData().getItemId() == menuItemId) {
          item.setOnTouchListener(onTouchListener);
        }
      }
    }
  }

  @Nullable
  public ColorStateList createDefaultColorStateList(int baseColorThemeAttr) {
    final TypedValue value = new TypedValue();
    if (!getContext().getTheme().resolveAttribute(baseColorThemeAttr, value, true)) {
      return null;
    }
    ColorStateList baseColor = AppCompatResources.getColorStateList(getContext(), value.resourceId);
    if (!getContext()
        .getTheme()
        .resolveAttribute(androidx.appcompat.R.attr.colorPrimary, value, true)) {
      return null;
    }
    int colorPrimary = value.data;
    int defaultColor = baseColor.getDefaultColor();
    return new ColorStateList(
        new int[][] {DISABLED_STATE_SET, CHECKED_STATE_SET, EMPTY_STATE_SET},
        new int[] {
          baseColor.getColorForState(DISABLED_STATE_SET, defaultColor), colorPrimary, defaultColor
        });
  }

  public void setPresenter(@NonNull NavigationBarPresenter presenter) {
    this.presenter = presenter;
  }

  @SuppressLint("ClickableViewAccessibility")
  public void buildMenuView() {
    removeAllViews();
    if (buttons != null) {
      for (NavigationBarItemView item : buttons) {
        if (item != null) {
          itemPool.release(item);
          item.clear();
        }
      }
    }

    if (menu.size() == 0) {
      selectedItemId = 0;
      selectedItemPosition = 0;
      buttons = null;
      return;
    }
    removeUnusedBadges();

    buttons = new NavigationBarItemView[menu.size()];
    boolean shifting = isShifting(labelVisibilityMode, menu.getVisibleItems().size());
    for (int i = 0; i < menu.size(); i++) {
      presenter.setUpdateSuspended(true);
      menu.getItem(i).setCheckable(true);
      presenter.setUpdateSuspended(false);
      NavigationBarItemView child = getNewItem();
      buttons[i] = child;
      child.setIconTintList(itemIconTint);
      child.setIconSize(itemIconSize);
      // Set the text color the default, then look for another text color in order of precedence.
      child.setTextColor(itemTextColorDefault);
      child.setTextAppearanceInactive(itemTextAppearanceInactive);
      child.setTextAppearanceActive(itemTextAppearanceActive);
      child.setTextColor(itemTextColorFromUser);
      if (itemPaddingTop != NO_PADDING) {
        child.setItemPaddingTop(itemPaddingTop);
      }
      if (itemPaddingBottom != NO_PADDING) {
        child.setItemPaddingBottom(itemPaddingBottom);
      }
      child.setActiveIndicatorWidth(itemActiveIndicatorWidth);
      child.setActiveIndicatorHeight(itemActiveIndicatorHeight);
      child.setActiveIndicatorMarginHorizontal(itemActiveIndicatorMarginHorizontal);
      child.setActiveIndicatorDrawable(createItemActiveIndicatorDrawable());
      child.setActiveIndicatorResizeable(itemActiveIndicatorResizeable);
      child.setActiveIndicatorEnabled(itemActiveIndicatorEnabled);
      if (itemBackground != null) {
        child.setItemBackground(itemBackground);
      } else {
        child.setItemBackground(itemBackgroundRes);
      }
      child.setShifting(shifting);
      child.setLabelVisibilityMode(labelVisibilityMode);
      MenuItemImpl item = (MenuItemImpl) menu.getItem(i);
      child.initialize(item, 0);
      child.setItemPosition(i);
      int itemId = item.getItemId();
      child.setOnTouchListener(onTouchListeners.get(itemId));
      child.setOnClickListener(onClickListener);
      if (selectedItemId != Menu.NONE && itemId == selectedItemId) {
        selectedItemPosition = i;
      }
      setBadgeIfNeeded(child);
      addView(child);
    }
    selectedItemPosition = Math.min(menu.size() - 1, selectedItemPosition);
    menu.getItem(selectedItemPosition).setChecked(true);
  }

  public void updateMenuView() {
    if (menu == null || buttons == null) {
      return;
    }

    final int menuSize = menu.size();
    if (menuSize != buttons.length) {
      // The size has changed. Rebuild menu view from scratch.
      buildMenuView();
      return;
    }

    int previousSelectedId = selectedItemId;

    for (int i = 0; i < menuSize; i++) {
      MenuItem item = menu.getItem(i);
      if (item.isChecked()) {
        selectedItemId = item.getItemId();
        selectedItemPosition = i;
      }
    }
    if (previousSelectedId != selectedItemId) {
      // Note: this has to be called before NavigationBarItemView#initialize().
      TransitionManager.beginDelayedTransition(this, set);
    }

    boolean shifting = isShifting(labelVisibilityMode, menu.getVisibleItems().size());
    for (int i = 0; i < menuSize; i++) {
      presenter.setUpdateSuspended(true);
      buttons[i].setLabelVisibilityMode(labelVisibilityMode);
      buttons[i].setShifting(shifting);
      buttons[i].initialize((MenuItemImpl) menu.getItem(i), 0);
      presenter.setUpdateSuspended(false);
    }
  }

  private NavigationBarItemView getNewItem() {
    NavigationBarItemView item = itemPool.acquire();
    if (item == null) {
      item = createNavigationBarItemView(getContext());
    }
    return item;
  }

  public int getSelectedItemId() {
    return selectedItemId;
  }

  protected boolean isShifting(
      @NavigationBarView.LabelVisibility int labelVisibilityMode, int childCount) {
    return labelVisibilityMode == NavigationBarView.LABEL_VISIBILITY_AUTO
        ? childCount > 3
        : labelVisibilityMode == NavigationBarView.LABEL_VISIBILITY_SELECTED;
  }

  void tryRestoreSelectedItemId(int itemId) {
    final int size = menu.size();
    for (int i = 0; i < size; i++) {
      MenuItem item = menu.getItem(i);
      if (itemId == item.getItemId()) {
        selectedItemId = itemId;
        selectedItemPosition = i;
        item.setChecked(true);
        break;
      }
    }
  }

  SparseArray<BadgeDrawable> getBadgeDrawables() {
    return badgeDrawables;
  }

  void restoreBadgeDrawables(SparseArray<BadgeDrawable> badgeDrawables) {
    for (int i = 0; i < badgeDrawables.size(); i++) {
      int key = badgeDrawables.keyAt(i);
      if (this.badgeDrawables.indexOfKey(key) < 0) {
        // badge doesn't exist yet, restore it
        this.badgeDrawables.append(key, badgeDrawables.get(key));
      }
    }
    if (buttons != null) {
      for (NavigationBarItemView itemView : buttons) {
        itemView.setBadge(this.badgeDrawables.get(itemView.getId()));
      }
    }
  }

  @Nullable
  public BadgeDrawable getBadge(int menuItemId) {
    return badgeDrawables.get(menuItemId);
  }

  /**
   * Creates an instance of {@link BadgeDrawable} if none exists. Initializes (if needed) and
   * returns the associated instance of {@link BadgeDrawable}.
   *
   * @param menuItemId Id of the menu item.
   * @return an instance of BadgeDrawable associated with {@code menuItemId}.
   */
  BadgeDrawable getOrCreateBadge(int menuItemId) {
    validateMenuItemId(menuItemId);
    BadgeDrawable badgeDrawable = badgeDrawables.get(menuItemId);
    // Create an instance of BadgeDrawable if none were already initialized for this menu item.
    if (badgeDrawable == null) {
      badgeDrawable = BadgeDrawable.create(getContext());
      badgeDrawables.put(menuItemId, badgeDrawable);
    }
    NavigationBarItemView itemView = findItemView(menuItemId);
    if (itemView != null) {
      itemView.setBadge(badgeDrawable);
    }
    return badgeDrawable;
  }

  void removeBadge(int menuItemId) {
    validateMenuItemId(menuItemId);
    BadgeDrawable badgeDrawable = badgeDrawables.get(menuItemId);
    NavigationBarItemView itemView = findItemView(menuItemId);
    if (itemView != null) {
      itemView.removeBadge();
    }
    if (badgeDrawable != null) {
      badgeDrawables.remove(menuItemId);
    }
  }

  private void setBadgeIfNeeded(@NonNull NavigationBarItemView child) {
    int childId = child.getId();
    if (!isValidId(childId)) {
      // Child doesn't have a valid id, do not set any BadgeDrawable on the view.
      return;
    }

    BadgeDrawable badgeDrawable = badgeDrawables.get(childId);
    if (badgeDrawable != null) {
      child.setBadge(badgeDrawable);
    }
  }

  private void removeUnusedBadges() {
    HashSet<Integer> activeKeys = new HashSet<>();
    // Remove keys from badgeDrawables that don't have a corresponding value in the menu.
    for (int i = 0; i < menu.size(); i++) {
      activeKeys.add(menu.getItem(i).getItemId());
    }

    for (int i = 0; i < badgeDrawables.size(); i++) {
      int key = badgeDrawables.keyAt(i);
      if (!activeKeys.contains(key)) {
        badgeDrawables.delete(key);
      }
    }
  }

  @Nullable
  public NavigationBarItemView findItemView(int menuItemId) {
    validateMenuItemId(menuItemId);
    if (buttons != null) {
      for (NavigationBarItemView itemView : buttons) {
        if (itemView.getId() == menuItemId) {
          return itemView;
        }
      }
    }
    return null;
  }

  /** Returns reference to newly created {@link NavigationBarItemView}. */
  @NonNull
  protected abstract NavigationBarItemView createNavigationBarItemView(@NonNull Context context);

  protected int getSelectedItemPosition() {
    return selectedItemPosition;
  }

  @Nullable
  protected MenuBuilder getMenu() {
    return menu;
  }

  private boolean isValidId(int viewId) {
    return viewId != View.NO_ID;
  }

  private void validateMenuItemId(int viewId) {
    if (!isValidId(viewId)) {
      throw new IllegalArgumentException(viewId + " is not a valid view id");
    }
  }
}