lib/java/com/google/android/material/navigationrail/NavigationRailView.java

/*
 * 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.google.android.material.navigationrail;

import com.google.android.material.R;

import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT;
import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
import static com.google.android.material.navigation.NavigationBarMenu.NO_MAX_ITEM_LIMIT;
import static java.lang.Math.max;
import static java.lang.Math.min;

import android.animation.TimeInterpolator;
import android.annotation.SuppressLint;
import android.content.Context;
import androidx.appcompat.widget.TintTypedArray;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.PathInterpolator;
import android.widget.FrameLayout;
import android.widget.ScrollView;
import androidx.annotation.LayoutRes;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.Px;
import androidx.annotation.RestrictTo;
import androidx.core.graphics.Insets;
import androidx.core.view.WindowInsetsCompat;
import androidx.transition.ChangeBounds;
import androidx.transition.Fade;
import androidx.transition.Transition;
import androidx.transition.TransitionManager;
import androidx.transition.TransitionSet;
import com.google.android.material.animation.AnimationUtils;
import com.google.android.material.internal.ThemeEnforcement;
import com.google.android.material.internal.ViewUtils;
import com.google.android.material.internal.ViewUtils.RelativePadding;
import com.google.android.material.navigation.NavigationBarDividerView;
import com.google.android.material.navigation.NavigationBarItemView;
import com.google.android.material.navigation.NavigationBarView;
import com.google.android.material.resources.MaterialResources;

/**
 * Represents a standard navigation rail view for application. It is an implementation of <a
 * href="https://material.io/components/navigation-rail">Material Design navigation rail.</a>.
 *
 * <p>Navigation rails make it easy for users to explore and switch between top-level views in a
 * single tap. They should be placed at the side edge of large screen devices such as tablets, when
 * an application has three to seven top-level destinations.
 *
 * <p>The bar contents can be populated by specifying a menu resource file. Each menu item title,
 * icon and enabled state will be used for displaying navigation rail bar items. Menu items can also
 * be used for programmatically selecting which destination is currently active. It can be done
 * using {@code MenuItem#setChecked(true)}.
 *
 * <p>A header view (such as a {@link
 * com.google.android.material.floatingactionbutton.FloatingActionButton}, logo, etc.) can be added
 * with the {@code app:headerLayout} attribute or by using {@link #addHeaderView}.
 *
 * <pre>
 * layout resource file:
 * &lt;com.google.android.material.navigationrail.NavigationRailView
 *     xmlns:android="http://schemas.android.com/apk/res/android"
 *     xmlns:app="http://schema.android.com/apk/res/res-auto"
 *     android:id="@+id/navigation"
 *     android:layout_width="wrap_content"
 *     android:layout_height="match_parent"
 *     app:menu="@menu/my_navigation_items"
 *     app:headerLayout="@layout/my_navigation_rail_fab" /&gt;
 *
 * res/menu/my_navigation_items.xml:
 * &lt;menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
 *     &lt;item android:id="@+id/action_search"
 *          android:title="@string/menu_search"
 *          android:icon="@drawable/ic_search" /&gt;
 *     &lt;item android:id="@+id/action_settings"
 *          android:title="@string/menu_settings"
 *          android:icon="@drawable/ic_add" /&gt;
 *     &lt;item android:id="@+id/action_navigation"
 *          android:title="@string/menu_navigation"
 *          android:icon="@drawable/ic_action_navigation_menu" /&gt;
 * &lt;/menu&gt;
 *
 * res/layout/my_navigation_rail_fab.xml:
 * &lt;com.google.android.material.floatingactionbutton.FloatingActionButton
 *     xmlns:android="http://schemas.android.com/apk/res/android"
 *     xmlns:app="http://schemas.android.com/apk/res-auto"
 *     android:id="@+id/my_navigation_rail_fab"
 *     android:layout_width="wrap_content"
 *     android:layout_height="wrap_content"
 *     android:contentDescription="@string/my_navigation_rail_fab_content_desc"
 *     app:srcCompat="@drawable/ic_add" /&gt;
 * </pre>
 *
 * <p>For more information, see the <a
 * href="https://github.com/material-components/material-components-android/blob/master/docs/components/NavigationRail.md">component
 * developer guidance</a> and <a
 * href="https://material.io/components/navigation-rail/overview">design guidelines</a>.
 */
public class NavigationRailView extends NavigationBarView {

  static final int DEFAULT_MENU_GRAVITY = Gravity.TOP | Gravity.CENTER_HORIZONTAL;
  static final int COLLAPSED_MAX_ITEM_COUNT = 7;
  private static final int DEFAULT_HEADER_GRAVITY = Gravity.TOP | Gravity.CENTER_HORIZONTAL;
  static final int NO_ITEM_MINIMUM_HEIGHT = -1;

  // These are the values for the cubic bezier curve to mimic the spring curve with a damping
  // ratio of 0.8 and stiffness value of 380.
  private static final int EXPAND_DURATION = 500;
  private static final TimeInterpolator CUBIC_BEZIER_INTERPOLATOR =
      new PathInterpolator(0.38f, 1.21f, 0.22f, 1.00f);

  private static final int FADE_DURATION = 100;

  private final int contentMarginTop;
  private final int headerMarginBottom;
  private final int minExpandedWidth;
  private final int maxExpandedWidth;
  private final boolean scrollingEnabled;
  private boolean submenuDividersEnabled;
  @Nullable private View headerView;
  @Nullable private Boolean paddingTopSystemWindowInsets = null;
  @Nullable private Boolean paddingBottomSystemWindowInsets = null;
  @Nullable private Boolean paddingStartSystemWindowInsets = null;

  private boolean expanded = false;
  private int collapsedItemSpacing;
  private int collapsedItemMinHeight = NO_ITEM_MINIMUM_HEIGHT;
  @ItemIconGravity private int collapsedIconGravity = ITEM_ICON_GRAVITY_TOP;
  @ItemGravity private int collapsedItemGravity = ITEM_GRAVITY_TOP_CENTER;

  private int expandedItemMinHeight;
  @ItemIconGravity private int expandedIconGravity;
  @ItemGravity private int expandedItemGravity;
  private int expandedItemSpacing;
  private NavigationRailFrameLayout contentContainer;

  public NavigationRailView(@NonNull Context context) {
    this(context, null);
  }

  public NavigationRailView(@NonNull Context context, @Nullable AttributeSet attrs) {
    this(context, attrs, R.attr.navigationRailStyle);
  }

  public NavigationRailView(
      @NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    this(context, attrs, defStyleAttr, R.style.Widget_MaterialComponents_NavigationRailView);
  }

  public NavigationRailView(
      @NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);

    // Ensure we are using the correctly themed context rather than the context that was passed in.
    context = getContext();
    expandedItemSpacing =
        getContext()
            .getResources()
            .getDimensionPixelSize(R.dimen.m3_navigation_rail_expanded_item_spacing);
    expandedItemGravity = ITEM_GRAVITY_START_CENTER;
    expandedIconGravity = ITEM_ICON_GRAVITY_START;

    /* Custom attributes */
    TintTypedArray attributes =
        ThemeEnforcement.obtainTintedStyledAttributes(
            context, attrs, R.styleable.NavigationRailView, defStyleAttr, defStyleRes);

    contentMarginTop =
        attributes.getDimensionPixelSize(
            R.styleable.NavigationRailView_contentMarginTop,
            getResources().getDimensionPixelSize(R.dimen.mtrl_navigation_rail_margin));
    headerMarginBottom =
        attributes.getDimensionPixelSize(R.styleable.NavigationRailView_headerMarginBottom,
            getResources().getDimensionPixelSize(R.dimen.mtrl_navigation_rail_margin));
    scrollingEnabled =
        attributes.getBoolean(R.styleable.NavigationRailView_scrollingEnabled, false);
    setSubmenuDividersEnabled(attributes.getBoolean(R.styleable.NavigationRailView_submenuDividersEnabled, false));

    addContentContainer();

    int headerLayoutRes = attributes.getResourceId(R.styleable.NavigationRailView_headerLayout, 0);
    if (headerLayoutRes != 0) {
      addHeaderView(headerLayoutRes);
    }

    setMenuGravity(
        attributes.getInt(R.styleable.NavigationRailView_menuGravity, DEFAULT_MENU_GRAVITY));

    int collapsedItemMinHeight = attributes.getDimensionPixelSize(
        R.styleable.NavigationRailView_itemMinHeight, NO_ITEM_MINIMUM_HEIGHT);
    int expandedItemMinHeight = attributes.getDimensionPixelSize(
        R.styleable.NavigationRailView_itemMinHeight, NO_ITEM_MINIMUM_HEIGHT);

    if (attributes.hasValue(R.styleable.NavigationRailView_collapsedItemMinHeight)) {
      collapsedItemMinHeight = attributes.getDimensionPixelSize(
          R.styleable.NavigationRailView_collapsedItemMinHeight, NO_ITEM_MINIMUM_HEIGHT);
    }
    if (attributes.hasValue(R.styleable.NavigationRailView_expandedItemMinHeight)) {
      expandedItemMinHeight = attributes.getDimensionPixelSize(
          R.styleable.NavigationRailView_expandedItemMinHeight, NO_ITEM_MINIMUM_HEIGHT);
    }
    setCollapsedItemMinimumHeight(collapsedItemMinHeight);
    setExpandedItemMinimumHeight(expandedItemMinHeight);
    minExpandedWidth = attributes.getDimensionPixelSize(
          R.styleable.NavigationRailView_expandedMinWidth,
          context
              .getResources()
              .getDimensionPixelSize(R.dimen.m3_navigation_rail_min_expanded_width));
    maxExpandedWidth = attributes.getDimensionPixelSize(
        R.styleable.NavigationRailView_expandedMaxWidth,
        context
            .getResources()
            .getDimensionPixelSize(R.dimen.m3_navigation_rail_max_expanded_width));

    if (attributes.hasValue(R.styleable.NavigationRailView_paddingTopSystemWindowInsets)) {
      paddingTopSystemWindowInsets =
          attributes.getBoolean(R.styleable.NavigationRailView_paddingTopSystemWindowInsets, false);
    }
    if (attributes.hasValue(R.styleable.NavigationRailView_paddingBottomSystemWindowInsets)) {
      paddingBottomSystemWindowInsets =
          attributes.getBoolean(
              R.styleable.NavigationRailView_paddingBottomSystemWindowInsets, false);
    }
    if (attributes.hasValue(R.styleable.NavigationRailView_paddingStartSystemWindowInsets)) {
      paddingStartSystemWindowInsets =
          attributes.getBoolean(
              R.styleable.NavigationRailView_paddingStartSystemWindowInsets, false);
    }

    int largeFontTopPadding =
        getResources()
            .getDimensionPixelOffset(R.dimen.m3_navigation_rail_item_padding_top_with_large_font);
    int largeFontBottomPadding =
        getResources()
            .getDimensionPixelOffset(
                R.dimen.m3_navigation_rail_item_padding_bottom_with_large_font);
    float progress =
        AnimationUtils.lerp(0F, 1F, .3F, 1F, MaterialResources.getFontScale(context) - 1F);
    float topPadding = AnimationUtils.lerp(getItemPaddingTop(), largeFontTopPadding, progress);
    float bottomPadding =
        AnimationUtils.lerp(getItemPaddingBottom(), largeFontBottomPadding, progress);
    setItemPaddingTop(Math.round(topPadding));
    setItemPaddingBottom(Math.round(bottomPadding));
    setCollapsedItemSpacing(
        attributes.getDimensionPixelSize(R.styleable.NavigationRailView_itemSpacing, 0));
    setExpanded(attributes.getBoolean(R.styleable.NavigationRailView_expanded, false));

    attributes.recycle();

    applyWindowInsets();
  }

  private void startTransitionAnimation() {
    if (!isLaidOut()) {
      return;
    }
    Transition changeBoundsTransition = new ChangeBounds().setDuration(EXPAND_DURATION)
        .setInterpolator(CUBIC_BEZIER_INTERPOLATOR);
    Transition labelFadeInTransition = new Fade().setDuration(FADE_DURATION);
    Transition labelFadeOutTransition = new Fade().setDuration(FADE_DURATION);
    Transition labelHorizontalMoveTransition = new LabelMoveTransition();
    Transition fadingItemsTransition = new Fade().setDuration(FADE_DURATION);
    // Remove all label groups from being targeted by ChangeBounds as we want a different transition
    // for it
    int childCount = getNavigationRailMenuView().getChildCount();
    for (int i = 0; i < childCount; i++) {
      View item = getNavigationRailMenuView().getChildAt(i);
      if (item instanceof NavigationBarItemView) {
        // Exclude labels from ChangeBounds transition
        changeBoundsTransition.excludeTarget(((NavigationBarItemView) item).getLabelGroup(), true);
        changeBoundsTransition.excludeTarget(
            ((NavigationBarItemView) item).getExpandedLabelGroup(), true);

        // If currently expanded, we are fading out the expanded label group and fading in the
        // collapsed label group
        if (expanded) {
          labelFadeOutTransition.addTarget(((NavigationBarItemView) item).getExpandedLabelGroup());
          labelFadeInTransition.addTarget(((NavigationBarItemView) item).getLabelGroup());
        } else {
          // Otherwise if we are collapsed, we fade out the collapsed label group and fade in the
          // expanded
          labelFadeOutTransition.addTarget(((NavigationBarItemView) item).getLabelGroup());
          labelFadeInTransition.addTarget(((NavigationBarItemView) item).getExpandedLabelGroup());
        }
        labelHorizontalMoveTransition.addTarget(
            ((NavigationBarItemView) item).getExpandedLabelGroup());
      }
      fadingItemsTransition.addTarget(item);
    }

    TransitionSet changeBoundsFadeLabelInTransition = new TransitionSet();
    changeBoundsFadeLabelInTransition.setOrdering(TransitionSet.ORDERING_TOGETHER);
    changeBoundsFadeLabelInTransition
        .addTransition(changeBoundsTransition)
        .addTransition(labelFadeInTransition)
        .addTransition(labelHorizontalMoveTransition);

    // If collapsed, we want to fade in the hidden nav items with the labels
    if (!expanded) {
      changeBoundsFadeLabelInTransition.addTransition(fadingItemsTransition);
    }

    TransitionSet fadeOutTransitions = new TransitionSet();
    fadeOutTransitions.setOrdering(TransitionSet.ORDERING_TOGETHER);
    fadeOutTransitions.addTransition(labelFadeOutTransition);

    // If expanded, we want to fade out the nav items to hide with the labels
    if (expanded) {
      fadeOutTransitions.addTransition(fadingItemsTransition);
    }

    TransitionSet transitionSet = new TransitionSet();
    transitionSet.setOrdering(TransitionSet.ORDERING_SEQUENTIAL);
    transitionSet
        .addTransition(fadeOutTransitions)
        .addTransition(changeBoundsFadeLabelInTransition);

    TransitionManager.beginDelayedTransition((ViewGroup) getParent(), transitionSet);
  }

  @Override
  public void setItemIconGravity(int itemIconGravity) {
    collapsedIconGravity = itemIconGravity;
    expandedIconGravity = itemIconGravity;
    super.setItemIconGravity(itemIconGravity);
  }

  @Override
  public int getItemIconGravity() {
    return getNavigationRailMenuView().getItemIconGravity();
  }

  @Override
  public void setItemGravity(int itemGravity) {
    collapsedItemGravity = itemGravity;
    expandedItemGravity = itemGravity;
    super.setItemGravity(itemGravity);
  }

  @Override
  public int getItemGravity() {
    return getNavigationRailMenuView().getItemGravity();
  }

  private void setExpanded(boolean expanded) {
    if (this.expanded == expanded) {
      return;
    }
    startTransitionAnimation();
    this.expanded = expanded;
    int iconGravity = collapsedIconGravity;
    int itemSpacing = collapsedItemSpacing;
    int itemMinHeight = collapsedItemMinHeight;
    int itemGravity = collapsedItemGravity;
    if (expanded) {
      iconGravity = expandedIconGravity;
      itemSpacing = expandedItemSpacing;
      itemMinHeight = expandedItemMinHeight;
      itemGravity = expandedItemGravity;
    }
    getNavigationRailMenuView().setItemGravity(itemGravity);
    super.setItemIconGravity(iconGravity);
    getNavigationRailMenuView().setItemSpacing(itemSpacing);
    getNavigationRailMenuView().setItemMinimumHeight(itemMinHeight);
    getNavigationRailMenuView().setExpanded(expanded);
  }

  /** Expand the navigation rail. */
  public void expand() {
    if (expanded) {
      return;
    }
    setExpanded(true);
    announceForAccessibility(getResources().getString(R.string.nav_rail_expanded_a11y_label));
  }

  /** Returns whether or not the navigation rail is currently expanded. **/
  public boolean isExpanded() {
    return expanded;
  }

  /** Collapse the navigation rail. */
  public void collapse() {
    if (!expanded) {
      return;
    }
    setExpanded(false);
    announceForAccessibility(getResources().getString(R.string.nav_rail_collapsed_a11y_label));
  }

  private void applyWindowInsets() {
    ViewUtils.doOnApplyWindowInsets(
        this,
        new ViewUtils.OnApplyWindowInsetsListener() {
          @NonNull
          @Override
          public WindowInsetsCompat onApplyWindowInsets(
              View view,
              @NonNull WindowInsetsCompat insets,
              @NonNull RelativePadding initialPadding) {
            // Apply the top, bottom, and start padding for a start edge aligned
            // NavigationRailView to dodge the system status/navigation bars and display cutouts
            Insets systemBarInsets = insets.getInsets(WindowInsetsCompat.Type.systemBars());
            Insets displayCutoutInsets = insets.getInsets(WindowInsetsCompat.Type.displayCutout());
            if (shouldApplyWindowInsetPadding(paddingTopSystemWindowInsets)) {
              initialPadding.top += systemBarInsets.top;
            }
            if (shouldApplyWindowInsetPadding(paddingBottomSystemWindowInsets)) {
              initialPadding.bottom += systemBarInsets.bottom;
            }
            if (shouldApplyWindowInsetPadding(paddingStartSystemWindowInsets)) {
              if (ViewUtils.isLayoutRtl(view)) {
                initialPadding.start += max(systemBarInsets.right, displayCutoutInsets.right);
              } else {
                initialPadding.start += max(systemBarInsets.left, displayCutoutInsets.left);
              }
            }
            initialPadding.applyToView(view);
            return insets;
          }
        });
  }

  /**
   * Whether the top or bottom of this view should be padded in to avoid the system window insets.
   *
   * <p>If the {@code paddingInsetFlag} is set, that value will take precedent. Otherwise,
   * fitsSystemWindow will be used.
   */
  private boolean shouldApplyWindowInsetPadding(Boolean paddingInsetFlag) {
    return paddingInsetFlag != null ? paddingInsetFlag : getFitsSystemWindows();
  }

  private int getMaxChildWidth() {
    int childCount = getNavigationRailMenuView().getChildCount();
    int maxChildWidth = 0;
    for (int i = 0; i < childCount; i++) {
      View child = getNavigationRailMenuView().getChildAt(i);
      if (child.getVisibility() != GONE && !(child instanceof NavigationBarDividerView)) {
        maxChildWidth = max(maxChildWidth, child.getMeasuredWidth());
      }
    }
    return maxChildWidth;
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int minWidthSpec = makeMinWidthSpec(widthMeasureSpec);
    if (expanded) {
      // Try measuring child with no other restrictions than existing measure spec
      measureChild(getNavigationRailMenuView(), widthMeasureSpec, heightMeasureSpec);
      if (headerView != null) {
        measureChild(headerView, widthMeasureSpec, heightMeasureSpec);
      }
      // Measure properly with the max child width
      minWidthSpec = makeExpandedWidthMeasureSpec(widthMeasureSpec, getMaxChildWidth());
      // If the active indicator is match_parent, it should be notified to update its width
      if (getItemActiveIndicatorExpandedWidth() == MATCH_PARENT) {
        getNavigationRailMenuView().updateActiveIndicator(MeasureSpec.getSize(minWidthSpec));
      }
    }
    super.onMeasure(minWidthSpec, heightMeasureSpec);
    // If the content container is measured to be less than the measured height of the nav rail,
    // we want to measure it to be exactly the height of the nav rail.
    if (contentContainer.getMeasuredHeight() < getMeasuredHeight()) {
      measureChild(
          contentContainer,
          minWidthSpec,
          MeasureSpec.makeMeasureSpec(getMeasuredHeight(), MeasureSpec.EXACTLY));
    }
  }

  /**
   * Adds the specified {@link View} layout resource, to appear at the top of the {@link
   * NavigationRailView}. If the view already has a header view attached to it, it will be removed
   * first.
   *
   * @param layoutRes the unique resource identifier to the layout that should be attached.
   * @see #addHeaderView(View)
   * @see #removeHeaderView()
   * @see #getHeaderView()
   */
  public void addHeaderView(@LayoutRes int layoutRes) {
    addHeaderView(LayoutInflater.from(getContext()).inflate(layoutRes, this, false));
  }

  /**
   * Adds the specified {@link View} if any, to appear at the top of the {@link NavigationRailView}.
   * If the view already has a header view attached to it, it will be removed first.
   *
   * @param headerView reference to the {@link View} that should be attached.
   * @see #addHeaderView(int)
   * @see #removeHeaderView()
   * @see #getHeaderView()
   */
  public void addHeaderView(@NonNull View headerView) {
    removeHeaderView();
    this.headerView = headerView;

    FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(WRAP_CONTENT, WRAP_CONTENT);
    params.gravity = DEFAULT_HEADER_GRAVITY;
    params.bottomMargin = headerMarginBottom;
    contentContainer.addView(headerView, /* index= */ 0, params);
  }

  /**
   * Returns reference to the header view if any, that is currently attached the {@link
   * NavigationRailView}.
   *
   * @see #addHeaderView(int)
   * @see #addHeaderView(View)
   * @see #removeHeaderView()
   */
  @Nullable
  public View getHeaderView() {
    return headerView;
  }

  /**
   * Removes the current header view if any, from the {@link NavigationRailView}.
   *
   * @see #addHeaderView(int)
   * @see #addHeaderView(View)
   * @see #getHeaderView()
   */
  public void removeHeaderView() {
    if (headerView != null) {
      contentContainer.removeView(headerView);
      headerView = null;
    }
  }

  /** Sets how destinations in the menu view will be grouped. */
  public void setMenuGravity(int gravity) {
    getNavigationRailMenuView().setMenuGravity(gravity);
  }

  /** Gets the current gravity setting for how destinations in the menu view will be grouped. */
  public int getMenuGravity() {
    return getNavigationRailMenuView().getMenuGravity();
  }

  /** Get the current minimum height each item in the navigation rail's menu should be. */
  public int getItemMinimumHeight() {
    return getNavigationRailMenuView().getItemMinimumHeight();
  }

  /**
   * Set the minimum height each item in the navigation rail's menu should use.
   *
   * <p>If this is unset (-1), each item will be at least as tall as the navigation rail is wide.
   */
  public void setItemMinimumHeight(@Px int minHeight) {
    collapsedItemMinHeight = minHeight;
    expandedItemMinHeight = minHeight;
    NavigationRailMenuView menuView = (NavigationRailMenuView) getMenuView();
    menuView.setItemMinimumHeight(minHeight);
  }

  /**
   * Sets the minimum height of a navigation rail menu item when the navigation rail is collapsed.
   *
   * @param minHeight the min height of the item when the nav rail is collapsed
   */
  public void setCollapsedItemMinimumHeight(@Px int minHeight) {
    collapsedItemMinHeight = minHeight;
    if (!expanded) {
      ((NavigationRailMenuView) getMenuView()).setItemMinimumHeight(minHeight);
    }
  }

  /**
   * Gets the minimum height of a navigation rail menu item when the navigation rail is collapsed.
   */
  public int getCollapsedItemMinimumHeight() {
    return collapsedItemMinHeight;
  }

  /**
   * Sets the minimum height of a navigation rail menu item when the navigation rail is expanded.
   *
   * @param minHeight the min height of the item when the nav rail is collapsed
   */
  public void setExpandedItemMinimumHeight(@Px int minHeight) {
    expandedItemMinHeight = minHeight;
    if (expanded) {
      ((NavigationRailMenuView) getMenuView()).setItemMinimumHeight(minHeight);
    }
  }

  /**
   * Gets the minimum height of a navigation rail menu item when the navigation rail is expanded.
   */
  public int getExpandedItemMinimumHeight() {
    return expandedItemMinHeight;
  }

  /**
   * Set whether or not to enable the dividers which go between each subgroup in the menu.
   */
  public void setSubmenuDividersEnabled(boolean submenuDividersEnabled) {
    if (this.submenuDividersEnabled == submenuDividersEnabled) {
      return;
    }
    this.submenuDividersEnabled = submenuDividersEnabled;
    getNavigationRailMenuView().setSubmenuDividersEnabled(submenuDividersEnabled);
  }

  /**
   * Get whether or not to enable the dividers which go between each subgroup in the menu.
   */
  public boolean getSubmenuDividersEnabled() {
    return submenuDividersEnabled;
  }

  /**
   * Set the padding in between the navigation rail menu items.
   */
  public void setItemSpacing(@Px int itemSpacing) {
    this.collapsedItemSpacing = itemSpacing;
    this.expandedItemSpacing = itemSpacing;
    getNavigationRailMenuView().setItemSpacing(itemSpacing);
  }

  /**
   * Sets the padding in between the navigation rail menu items when the navigation rail is
   * collapsed.
   *
   * @param itemSpacing the desired item spacing in between the items when the nav rail is collapsed
   */
  public void setCollapsedItemSpacing(@Px int itemSpacing) {
    this.collapsedItemSpacing = itemSpacing;
    if (!expanded) {
      getNavigationRailMenuView().setItemSpacing(itemSpacing);
    }
  }

  /** Get the current padding in between the navigation rail menu items. */
  public int getItemSpacing() {
    return getNavigationRailMenuView().getItemSpacing();
  }

  @Override
  public int getMaxItemCount() {
    return NO_MAX_ITEM_LIMIT;
  }

  /** @hide */
  @RestrictTo(LIBRARY_GROUP)
  @Override
  public int getCollapsedMaxItemCount() {
    return COLLAPSED_MAX_ITEM_COUNT;
  }

  private NavigationRailMenuView getNavigationRailMenuView() {
    return (NavigationRailMenuView) getMenuView();
  }

  /** @hide */
  @RestrictTo(LIBRARY_GROUP)
  @Override
  @NonNull
  protected NavigationRailMenuView createNavigationBarMenuView(@NonNull Context context) {
    return new NavigationRailMenuView(context);
  }

  private int makeMinWidthSpec(int measureSpec) {
    int minWidth = getSuggestedMinimumWidth();
    if (MeasureSpec.getMode(measureSpec) != MeasureSpec.EXACTLY && minWidth > 0) {
      minWidth += getPaddingLeft() + getPaddingRight();

      return MeasureSpec.makeMeasureSpec(
          min(MeasureSpec.getSize(measureSpec), minWidth), MeasureSpec.EXACTLY);
    }
    return measureSpec;
  }

  private int makeExpandedWidthMeasureSpec(int measureSpec, int measuredWidth) {
    int minWidth = min(minExpandedWidth, MeasureSpec.getSize(measureSpec));

    if (MeasureSpec.getMode(measureSpec) != MeasureSpec.EXACTLY) {
      int newWidth = max(measuredWidth, minWidth);
      // Also take into account header view max
      if (headerView != null) {
        newWidth = max(newWidth, headerView.getMeasuredWidth());
      }
      newWidth = max(getSuggestedMinimumWidth(), min(newWidth, maxExpandedWidth));
      return MeasureSpec.makeMeasureSpec(newWidth, MeasureSpec.EXACTLY);
    }

    return measureSpec;
  }

  @Override
  protected boolean isSubMenuSupported() {
    return true;
  }

  private void addContentContainer() {
    View menuView = (View) getMenuView();
    contentContainer = new NavigationRailFrameLayout(getContext());
    contentContainer.setPaddingTop(contentMarginTop);
    contentContainer.setScrollingEnabled(scrollingEnabled);
    contentContainer.setClipChildren(false);
    contentContainer.setLayoutParams(new FrameLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT));
    menuView.setLayoutParams(new FrameLayout.LayoutParams(WRAP_CONTENT, WRAP_CONTENT));
    contentContainer.addView(menuView);

    if (!scrollingEnabled) {
      addView(contentContainer);
      return;
    }

    ScrollView scrollView = new ScrollView(getContext());
    scrollView.setVerticalScrollBarEnabled(false);
    scrollView.addView(contentContainer);
    scrollView.setLayoutParams(new FrameLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT));
    addView(scrollView);
  }

  /** @hide */
  @RestrictTo(LIBRARY_GROUP)
  @Override
  public boolean shouldAddMenuView() {
    return true;
  }

  @SuppressLint("ClickableViewAccessibility")
  @Override
  public boolean onTouchEvent(@NonNull MotionEvent event) {
    super.onTouchEvent(event);
    // Consume all events to avoid views under the NavigationRailView from receiving touch events.
    return true;
  }
}