BaseTransientBottomBar.java

/*
 * Copyright (C) 2015 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.snackbar;

import com.google.android.material.R;

import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
import static com.google.android.material.animation.AnimationUtils.FAST_OUT_SLOW_IN_INTERPOLATOR;
import static com.google.android.material.animation.AnimationUtils.LINEAR_INTERPOLATOR;
import static com.google.android.material.animation.AnimationUtils.LINEAR_OUT_SLOW_IN_INTERPOLATOR;
import static com.google.android.material.theme.overlay.MaterialThemeOverlay.wrap;

import android.accessibilityservice.AccessibilityServiceInfo;
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.AnimatorSet;
import android.animation.ValueAnimator;
import android.animation.ValueAnimator.AnimatorUpdateListener;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.ColorStateList;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.PorterDuff;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.GradientDrawable;
import android.os.Build;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.view.ViewGroup.MarginLayoutParams;
import android.view.ViewParent;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.view.WindowInsets;
import android.view.WindowManager;
import android.view.accessibility.AccessibilityManager;
import android.widget.FrameLayout;
import androidx.annotation.ColorInt;
import androidx.annotation.IdRes;
import androidx.annotation.IntDef;
import androidx.annotation.IntRange;
import androidx.annotation.LayoutRes;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RequiresApi;
import androidx.annotation.RestrictTo;
import androidx.coordinatorlayout.widget.CoordinatorLayout;
import androidx.core.graphics.drawable.DrawableCompat;
import androidx.core.view.AccessibilityDelegateCompat;
import androidx.core.view.OnApplyWindowInsetsListener;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
import androidx.core.view.accessibility.AccessibilityNodeInfoCompat;
import com.google.android.material.behavior.SwipeDismissBehavior;
import com.google.android.material.color.MaterialColors;
import com.google.android.material.internal.ThemeEnforcement;
import com.google.android.material.internal.ViewUtils;
import com.google.android.material.resources.MaterialResources;
import com.google.android.material.shape.MaterialShapeDrawable;
import com.google.android.material.shape.ShapeAppearanceModel;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.List;

/**
 * Base class for lightweight transient bars that are displayed along the bottom edge of the
 * application window.
 *
 * @param <B> The transient bottom bar subclass.
 */
public abstract class BaseTransientBottomBar<B extends BaseTransientBottomBar<B>> {

  /** Animation mode that corresponds to the slide in and out animations. */
  public static final int ANIMATION_MODE_SLIDE = 0;

  /** Animation mode that corresponds to the fade in and out animations. */
  public static final int ANIMATION_MODE_FADE = 1;

  /**
   * Animation modes that can be set on the {@link BaseTransientBottomBar}.
   *
   * @hide
   */
  @RestrictTo(LIBRARY_GROUP)
  @IntDef({ANIMATION_MODE_SLIDE, ANIMATION_MODE_FADE})
  @Retention(RetentionPolicy.SOURCE)
  public @interface AnimationMode {}

  /**
   * Base class for {@link BaseTransientBottomBar} callbacks.
   *
   * @param <B> The transient bottom bar subclass.
   * @see BaseTransientBottomBar#addCallback(BaseCallback)
   */
  public abstract static class BaseCallback<B> {
    /** Indicates that the Snackbar was dismissed via a swipe. */
    public static final int DISMISS_EVENT_SWIPE = 0;
    /** Indicates that the Snackbar was dismissed via an action click. */
    public static final int DISMISS_EVENT_ACTION = 1;
    /** Indicates that the Snackbar was dismissed via a timeout. */
    public static final int DISMISS_EVENT_TIMEOUT = 2;
    /** Indicates that the Snackbar was dismissed via a call to {@link #dismiss()}. */
    public static final int DISMISS_EVENT_MANUAL = 3;
    /** Indicates that the Snackbar was dismissed from a new Snackbar being shown. */
    public static final int DISMISS_EVENT_CONSECUTIVE = 4;

    /**
     * Annotation for types of Dismiss events.
     *
     * @hide
     */
    @RestrictTo(LIBRARY_GROUP)
    @IntDef({
      DISMISS_EVENT_SWIPE,
      DISMISS_EVENT_ACTION,
      DISMISS_EVENT_TIMEOUT,
      DISMISS_EVENT_MANUAL,
      DISMISS_EVENT_CONSECUTIVE
    })
    @Retention(RetentionPolicy.SOURCE)
    public @interface DismissEvent {}

    /**
     * Called when the given {@link BaseTransientBottomBar} has been dismissed, either through a
     * time-out, having been manually dismissed, or an action being clicked.
     *
     * @param transientBottomBar The transient bottom bar which has been dismissed.
     * @param event The event which caused the dismissal. One of either: {@link
     *     #DISMISS_EVENT_SWIPE}, {@link #DISMISS_EVENT_ACTION}, {@link #DISMISS_EVENT_TIMEOUT},
     *     {@link #DISMISS_EVENT_MANUAL} or {@link #DISMISS_EVENT_CONSECUTIVE}.
     * @see BaseTransientBottomBar#dismiss()
     */
    public void onDismissed(B transientBottomBar, @DismissEvent int event) {
      // empty
    }

    /**
     * Called when the given {@link BaseTransientBottomBar} is visible.
     *
     * @param transientBottomBar The transient bottom bar which is now visible.
     * @see BaseTransientBottomBar#show()
     */
    public void onShown(B transientBottomBar) {
      // empty
    }
  }

  /**
   * Interface that defines the behavior of the main content of a transient bottom bar.
   *
   * @deprecated Use {@link com.google.android.material.snackbar.ContentViewCallback} instead.
   */
  @Deprecated
  public interface ContentViewCallback
      extends com.google.android.material.snackbar.ContentViewCallback {}

  /** @hide */
  @RestrictTo(LIBRARY_GROUP)
  @IntRange(from = LENGTH_INDEFINITE)
  @Retention(RetentionPolicy.SOURCE)
  public @interface Duration {}

  /**
   * Show the Snackbar indefinitely. This means that the Snackbar will be displayed from the time
   * that is {@link #show() shown} until either it is dismissed, or another Snackbar is shown.
   *
   * @see #setDuration
   */
  public static final int LENGTH_INDEFINITE = -2;

  /**
   * Show the Snackbar for a short period of time.
   *
   * @see #setDuration
   */
  public static final int LENGTH_SHORT = -1;

  /**
   * Show the Snackbar for a long period of time.
   *
   * @see #setDuration
   */
  public static final int LENGTH_LONG = 0;

  // Legacy slide animation duration constant.
  static final int ANIMATION_DURATION = 250;
  // Legacy slide animation content fade duration constant.
  static final int ANIMATION_FADE_DURATION = 180;

  // Fade and scale animation constants.
  private static final int ANIMATION_FADE_IN_DURATION = 150;
  private static final int ANIMATION_FADE_OUT_DURATION = 75;
  private static final float ANIMATION_SCALE_FROM_VALUE = 0.8f;

  @NonNull static final Handler handler;
  static final int MSG_SHOW = 0;
  static final int MSG_DISMISS = 1;

  // On JB/KK versions of the platform sometimes View.setTranslationY does not result in
  // layout / draw pass, and CoordinatorLayout relies on a draw pass to happen to sync vertical
  // positioning of all its child views
  private static final boolean USE_OFFSET_API =
      (Build.VERSION.SDK_INT >= VERSION_CODES.JELLY_BEAN)
          && (Build.VERSION.SDK_INT <= VERSION_CODES.KITKAT);

  private static final int[] SNACKBAR_STYLE_ATTR = new int[] {R.attr.snackbarStyle};

  private static final String TAG = BaseTransientBottomBar.class.getSimpleName();

  static {
    handler =
        new Handler(
            Looper.getMainLooper(),
            new Handler.Callback() {
              @Override
              public boolean handleMessage(@NonNull Message message) {
                switch (message.what) {
                  case MSG_SHOW:
                    ((BaseTransientBottomBar) message.obj).showView();
                    return true;
                  case MSG_DISMISS:
                    ((BaseTransientBottomBar) message.obj).hideView(message.arg1);
                    return true;
                  default:
                    return false;
                }
              }
            });
  }

  @NonNull private final ViewGroup targetParent;
  private final Context context;
  @NonNull protected final SnackbarBaseLayout view;

  @NonNull
  private final com.google.android.material.snackbar.ContentViewCallback contentViewCallback;

  private int duration;
  private boolean gestureInsetBottomIgnored;

  @Nullable
  private Anchor anchor;

  private boolean anchorViewLayoutListenerEnabled = false;

  @RequiresApi(VERSION_CODES.Q)
  private final Runnable bottomMarginGestureInsetRunnable =
      new Runnable() {
        @Override
        public void run() {
          if (view == null || context == null) {
            return;
          }
          // Calculate current bottom inset, factoring in translationY to account for where the
          // view will likely be animating to.
          int currentInsetBottom =
              getScreenHeight() - getViewAbsoluteBottom() + (int) view.getTranslationY();
          if (currentInsetBottom >= extraBottomMarginGestureInset) {
            // No need to add extra offset if view is already outside of bottom gesture area
            return;
          }

          LayoutParams layoutParams = view.getLayoutParams();
          if (!(layoutParams instanceof MarginLayoutParams)) {
            Log.w(
                TAG,
                "Unable to apply gesture inset because layout params are not MarginLayoutParams");
            return;
          }

          // Move view outside of bottom gesture area
          MarginLayoutParams marginParams = (MarginLayoutParams) layoutParams;
          marginParams.bottomMargin += extraBottomMarginGestureInset - currentInsetBottom;
          view.requestLayout();
        }
      };

  private int extraBottomMarginWindowInset;
  private int extraLeftMarginWindowInset;
  private int extraRightMarginWindowInset;
  private int extraBottomMarginGestureInset;
  private int extraBottomMarginAnchorView;

  private boolean pendingShowingView;

  private List<BaseCallback<B>> callbacks;

  private BaseTransientBottomBar.Behavior behavior;

  @Nullable private final AccessibilityManager accessibilityManager;

  /**
   * Constructor for the transient bottom bar.
   *
   * <p>Uses {@link Context} from {@code parent}.
   *
   * @param parent The parent for this transient bottom bar.
   * @param content The content view for this transient bottom bar.
   * @param contentViewCallback The content view callback for this transient bottom bar.
   */
  protected BaseTransientBottomBar(
      @NonNull ViewGroup parent,
      @NonNull View content,
      @NonNull com.google.android.material.snackbar.ContentViewCallback contentViewCallback) {
    this(parent.getContext(), parent, content, contentViewCallback);
  }

  protected BaseTransientBottomBar(
      @NonNull Context context,
      @NonNull ViewGroup parent,
      @NonNull View content,
      @NonNull com.google.android.material.snackbar.ContentViewCallback contentViewCallback) {
    if (parent == null) {
      throw new IllegalArgumentException("Transient bottom bar must have non-null parent");
    }
    if (content == null) {
      throw new IllegalArgumentException("Transient bottom bar must have non-null content");
    }
    if (contentViewCallback == null) {
      throw new IllegalArgumentException("Transient bottom bar must have non-null callback");
    }

    targetParent = parent;
    this.contentViewCallback = contentViewCallback;
    this.context = context;

    ThemeEnforcement.checkAppCompatTheme(context);

    LayoutInflater inflater = LayoutInflater.from(context);
    // Note that for backwards compatibility reasons we inflate a layout that is defined
    // in the extending Snackbar class. This is to prevent breakage of apps that have custom
    // coordinator layout behaviors that depend on that layout.
    view = (SnackbarBaseLayout) inflater.inflate(getSnackbarBaseLayoutResId(), targetParent, false);
    view.setBaseTransientBottomBar(this);
    if (content instanceof SnackbarContentLayout) {
      ((SnackbarContentLayout) content)
          .updateActionTextColorAlphaIfNeeded(view.getActionTextColorAlpha());
      ((SnackbarContentLayout) content).setMaxInlineActionWidth(view.getMaxInlineActionWidth());
    }
    view.addView(content);

    ViewCompat.setAccessibilityLiveRegion(view, ViewCompat.ACCESSIBILITY_LIVE_REGION_POLITE);
    ViewCompat.setImportantForAccessibility(view, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES);

    // Make sure that we fit system windows and have a listener to apply any insets
    ViewCompat.setFitsSystemWindows(view, true);
    ViewCompat.setOnApplyWindowInsetsListener(
        view,
        new OnApplyWindowInsetsListener() {
          @NonNull
          @Override
          public WindowInsetsCompat onApplyWindowInsets(
              View v, @NonNull WindowInsetsCompat insets) {
            // Save window insets for additional margins, e.g., to dodge the system navigation bar
            extraBottomMarginWindowInset = insets.getSystemWindowInsetBottom();
            extraLeftMarginWindowInset = insets.getSystemWindowInsetLeft();
            extraRightMarginWindowInset = insets.getSystemWindowInsetRight();
            updateMargins();
            return insets;
          }
        });

    // Handle accessibility events
    ViewCompat.setAccessibilityDelegate(
        view,
        new AccessibilityDelegateCompat() {
          @Override
          public void onInitializeAccessibilityNodeInfo(
              View host, @NonNull AccessibilityNodeInfoCompat info) {
            super.onInitializeAccessibilityNodeInfo(host, info);
            info.addAction(AccessibilityNodeInfoCompat.ACTION_DISMISS);
            info.setDismissable(true);
          }

          @Override
          public boolean performAccessibilityAction(View host, int action, Bundle args) {
            if (action == AccessibilityNodeInfoCompat.ACTION_DISMISS) {
              dismiss();
              return true;
            }
            return super.performAccessibilityAction(host, action, args);
          }
        });

    accessibilityManager =
        (AccessibilityManager) context.getSystemService(Context.ACCESSIBILITY_SERVICE);
  }

  private void updateMargins() {
    LayoutParams layoutParams = view.getLayoutParams();
    if (!(layoutParams instanceof MarginLayoutParams) || view.originalMargins == null) {
      Log.w(TAG, "Unable to update margins because layout params are not MarginLayoutParams");
      return;
    }
    if (view.getParent() == null) {
      // Parent will set layout params to view again. Wait for addView() is done to update layout
      // params, in case we save the already updated margins as the original margins.
      return;
    }

    int extraBottomMargin =
        getAnchorView() != null ? extraBottomMarginAnchorView : extraBottomMarginWindowInset;
    MarginLayoutParams marginParams = (MarginLayoutParams) layoutParams;
    marginParams.bottomMargin = view.originalMargins.bottom + extraBottomMargin;
    marginParams.leftMargin = view.originalMargins.left + extraLeftMarginWindowInset;
    marginParams.rightMargin = view.originalMargins.right + extraRightMarginWindowInset;
    marginParams.topMargin = view.originalMargins.top;
    view.requestLayout();

    if (VERSION.SDK_INT >= VERSION_CODES.Q && shouldUpdateGestureInset()) {
      // Ensure there is only one gesture inset runnable running at a time
      view.removeCallbacks(bottomMarginGestureInsetRunnable);
      view.post(bottomMarginGestureInsetRunnable);
    }
  }

  private boolean shouldUpdateGestureInset() {
    return extraBottomMarginGestureInset > 0 && !gestureInsetBottomIgnored && isSwipeDismissable();
  }

  private boolean isSwipeDismissable() {
    LayoutParams layoutParams = view.getLayoutParams();
    return layoutParams instanceof CoordinatorLayout.LayoutParams
        && ((CoordinatorLayout.LayoutParams) layoutParams).getBehavior()
            instanceof SwipeDismissBehavior;
  }

  @LayoutRes
  protected int getSnackbarBaseLayoutResId() {
    return hasSnackbarStyleAttr() ? R.layout.mtrl_layout_snackbar : R.layout.design_layout_snackbar;
  }

  /**
   * {@link Snackbar}s should still work with AppCompat themes, which don't specify a {@code
   * snackbarStyle}. This method helps to check if a valid {@code snackbarStyle} is set within the
   * current context, so that we know whether we can use the attribute.
   */
  protected boolean hasSnackbarStyleAttr() {
    TypedArray a = context.obtainStyledAttributes(SNACKBAR_STYLE_ATTR);
    int snackbarStyleResId = a.getResourceId(0, -1);
    a.recycle();
    return snackbarStyleResId != -1;
  }

  /**
   * Set how long to show the view for.
   *
   * @param duration How long to display the message. Can be {@link #LENGTH_SHORT}, {@link
   *     #LENGTH_LONG}, {@link #LENGTH_INDEFINITE}, or a custom duration in milliseconds.
   */
  @NonNull
  public B setDuration(@Duration int duration) {
    this.duration = duration;
    return (B) this;
  }

  /**
   * Return the duration.
   *
   * @see #setDuration
   */
  @Duration
  public int getDuration() {
    return duration;
  }

  /**
   * Sets whether this bottom bar should adjust it's position based on the system gesture area on
   * Android Q and above.
   *
   * <p>Note: the bottom bar will only adjust it's position if it is dismissable via swipe (because
   * that would cause a gesture conflict), gesture navigation is enabled, and this {@code
   * gestureInsetBottomIgnored} flag is false.
   */
  @NonNull
  public B setGestureInsetBottomIgnored(boolean gestureInsetBottomIgnored) {
    this.gestureInsetBottomIgnored = gestureInsetBottomIgnored;
    return (B) this;
  }

  /**
   * Returns whether this bottom bar should adjust it's position based on the system gesture area on
   * Android Q and above. See {@link #setGestureInsetBottomIgnored(boolean)}.
   */
  public boolean isGestureInsetBottomIgnored() {
    return gestureInsetBottomIgnored;
  }

  /**
   * Returns the animation mode.
   *
   * @see #setAnimationMode(int)
   */
  @AnimationMode
  public int getAnimationMode() {
    return view.getAnimationMode();
  }

  /**
   * Sets the animation mode.
   *
   * @param animationMode of {@link #ANIMATION_MODE_SLIDE} or {@link #ANIMATION_MODE_FADE}.
   * @see #getAnimationMode()
   */
  @NonNull
  public B setAnimationMode(@AnimationMode int animationMode) {
    view.setAnimationMode(animationMode);
    return (B) this;
  }

  /**
   * Returns the anchor view for this {@link BaseTransientBottomBar}.
   *
   * @see #setAnchorView(View)
   */
  @Nullable
  public View getAnchorView() {
    return anchor == null ? null : anchor.getAnchorView();
  }

  /** Sets the view the {@link BaseTransientBottomBar} should be anchored above. */
  @NonNull
  public B setAnchorView(@Nullable View anchorView) {
    if (this.anchor != null) {
      this.anchor.unanchor();
    }
    this.anchor = anchorView == null ? null : Anchor.anchor(this, anchorView);
    return (B) this;
  }

  /**
   * Sets the view the {@link BaseTransientBottomBar} should be anchored above by id.
   *
   * @throws IllegalArgumentException if the anchor view is not found.
   */
  @NonNull
  public B setAnchorView(@IdRes int anchorViewId) {
    View anchorView = targetParent.findViewById(anchorViewId);
    if (anchorView == null) {
      throw new IllegalArgumentException("Unable to find anchor view with id: " + anchorViewId);
    }
    return setAnchorView(anchorView);
  }

  /**
   * Returns whether the anchor view layout listener is enabled.
   *
   * @see #setAnchorViewLayoutListenerEnabled(boolean)
   */
  public boolean isAnchorViewLayoutListenerEnabled() {
    return anchorViewLayoutListenerEnabled;
  }

  /**
   * Sets whether the anchor view layout listener is enabled. If enabled, the {@link
   * BaseTransientBottomBar} will recalculate and update its position when the position of the
   * anchor view is changed.
   */
  public void setAnchorViewLayoutListenerEnabled(boolean anchorViewLayoutListenerEnabled) {
    this.anchorViewLayoutListenerEnabled = anchorViewLayoutListenerEnabled;
  }

  /**
   * Sets the {@link BaseTransientBottomBar.Behavior} to be used in this {@link
   * BaseTransientBottomBar}.
   *
   * @param behavior {@link BaseTransientBottomBar.Behavior} to be applied.
   */
  @NonNull
  public B setBehavior(BaseTransientBottomBar.Behavior behavior) {
    this.behavior = behavior;
    return (B) this;
  }

  /**
   * Return the behavior.
   *
   * @see #setBehavior(BaseTransientBottomBar.Behavior)
   */
  public BaseTransientBottomBar.Behavior getBehavior() {
    return behavior;
  }

  /** Returns the {@link BaseTransientBottomBar}'s context. */
  @NonNull
  public Context getContext() {
    return context;
  }

  /** Returns the {@link BaseTransientBottomBar}'s view. */
  @NonNull
  public View getView() {
    return view;
  }

  /** Show the {@link BaseTransientBottomBar}. */
  public void show() {
    SnackbarManager.getInstance().show(getDuration(), managerCallback);
  }

  /** Dismiss the {@link BaseTransientBottomBar}. */
  public void dismiss() {
    dispatchDismiss(BaseCallback.DISMISS_EVENT_MANUAL);
  }

  protected void dispatchDismiss(@BaseCallback.DismissEvent int event) {
    SnackbarManager.getInstance().dismiss(managerCallback, event);
  }

  /**
   * Adds the specified callback to the list of callbacks that will be notified of transient bottom
   * bar events.
   *
   * @param callback Callback to notify when transient bottom bar events occur.
   * @see #removeCallback(BaseCallback)
   */
  @NonNull
  public B addCallback(@Nullable BaseCallback<B> callback) {
    if (callback == null) {
      return (B) this;
    }
    if (callbacks == null) {
      callbacks = new ArrayList<BaseCallback<B>>();
    }
    callbacks.add(callback);
    return (B) this;
  }

  /**
   * Removes the specified callback from the list of callbacks that will be notified of transient
   * bottom bar events.
   *
   * @param callback Callback to remove from being notified of transient bottom bar events
   * @see #addCallback(BaseCallback)
   */
  @NonNull
  public B removeCallback(@Nullable BaseCallback<B> callback) {
    if (callback == null) {
      return (B) this;
    }
    if (callbacks == null) {
      // This can happen if this method is called before the first call to addCallback
      return (B) this;
    }
    callbacks.remove(callback);
    return (B) this;
  }

  /** Return whether this {@link BaseTransientBottomBar} is currently being shown. */
  public boolean isShown() {
    return SnackbarManager.getInstance().isCurrent(managerCallback);
  }

  /**
   * Returns whether this {@link BaseTransientBottomBar} is currently being shown, or is queued to
   * be shown next.
   */
  public boolean isShownOrQueued() {
    return SnackbarManager.getInstance().isCurrentOrNext(managerCallback);
  }

  @NonNull
  SnackbarManager.Callback managerCallback =
      new SnackbarManager.Callback() {
        @Override
        public void show() {
          handler.sendMessage(handler.obtainMessage(MSG_SHOW, BaseTransientBottomBar.this));
        }

        @Override
        public void dismiss(int event) {
          handler.sendMessage(
              handler.obtainMessage(MSG_DISMISS, event, 0, BaseTransientBottomBar.this));
        }
      };

  @NonNull
  protected SwipeDismissBehavior<? extends View> getNewBehavior() {
    return new Behavior();
  }

  final void showView() {
    if (this.view.getParent() == null) {
      ViewGroup.LayoutParams lp = this.view.getLayoutParams();

      if (lp instanceof CoordinatorLayout.LayoutParams) {
        setUpBehavior((CoordinatorLayout.LayoutParams) lp);
      }

      targetParent.addView(this.view);
      recalculateAndUpdateMargins();

      // Set view to INVISIBLE so it doesn't flash on the screen before the inset adjustment is
      // handled and the enter animation is started
      view.setVisibility(View.INVISIBLE);
    }

    if (ViewCompat.isLaidOut(this.view)) {
      showViewImpl();
      return;
    }

    // Otherwise, show it in when laid out
    pendingShowingView = true;
  }

  void onAttachedToWindow() {
    if (VERSION.SDK_INT >= VERSION_CODES.Q) {
      WindowInsets insets = view.getRootWindowInsets();
      if (insets != null) {
        extraBottomMarginGestureInset = insets.getMandatorySystemGestureInsets().bottom;
        updateMargins();
      }
    }
  }

  void onDetachedFromWindow() {
    if (isShownOrQueued()) {
      // If we haven't already been dismissed then this event is coming from a
      // non-user initiated action. Hence we need to make sure that we callback
      // and keep our state up to date. We need to post the call since
      // removeView() will call through to onDetachedFromWindow and thus overflow.
      handler.post(
          new Runnable() {
            @Override
            public void run() {
              onViewHidden(BaseCallback.DISMISS_EVENT_MANUAL);
            }
          });
    }
  }

  void onLayoutChange() {
    if (pendingShowingView) {
      BaseTransientBottomBar.this.showViewImpl();
      pendingShowingView = false;
    }
  }

  private void showViewImpl() {
    if (shouldAnimate()) {
      // If animations are enabled, animate it in
      animateViewIn();
    } else {
      // Else if animations are disabled, just make view VISIBLE and call back now
      if (view.getParent() != null) {
        view.setVisibility(View.VISIBLE);
      }
      onViewShown();
    }
  }

  private int getViewAbsoluteBottom() {
    int[] absoluteLocation = new int[2];
    view.getLocationOnScreen(absoluteLocation);
    return absoluteLocation[1] + view.getHeight();
  }

  @RequiresApi(VERSION_CODES.JELLY_BEAN_MR1)
  private int getScreenHeight() {
    WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
    DisplayMetrics displayMetrics = new DisplayMetrics();
    windowManager.getDefaultDisplay().getRealMetrics(displayMetrics);
    return displayMetrics.heightPixels;
  }

  private void setUpBehavior(CoordinatorLayout.LayoutParams lp) {
    // If our LayoutParams are from a CoordinatorLayout, we'll setup our Behavior
    CoordinatorLayout.LayoutParams clp = lp;

    SwipeDismissBehavior<? extends View> behavior =
        this.behavior == null ? getNewBehavior() : this.behavior;

    if (behavior instanceof BaseTransientBottomBar.Behavior) {
      ((Behavior) behavior).setBaseTransientBottomBar(this);
    }

    behavior.setListener(
        new SwipeDismissBehavior.OnDismissListener() {
          @Override
          public void onDismiss(@NonNull View view) {
            if (view.getParent() != null) {
              view.setVisibility(View.GONE);
            }
            dispatchDismiss(BaseCallback.DISMISS_EVENT_SWIPE);
          }

          @Override
          public void onDragStateChanged(int state) {
            switch (state) {
              case SwipeDismissBehavior.STATE_DRAGGING:
              case SwipeDismissBehavior.STATE_SETTLING:
                // If the view is being dragged or settling, pause the timeout
                SnackbarManager.getInstance().pauseTimeout(managerCallback);
                break;
              case SwipeDismissBehavior.STATE_IDLE:
                // If the view has been released and is idle, restore the timeout
                SnackbarManager.getInstance().restoreTimeoutIfPaused(managerCallback);
                break;
              default:
                // Any other state is ignored
            }
          }
        });
    clp.setBehavior(behavior);
    // Also set the inset edge so that views can dodge the bar correctly, but only if there is
    // no anchor view.
    if (getAnchorView() == null) {
      clp.insetEdge = Gravity.BOTTOM;
    }
  }

  private void recalculateAndUpdateMargins() {
    extraBottomMarginAnchorView = calculateBottomMarginForAnchorView();
    updateMargins();
  }

  private int calculateBottomMarginForAnchorView() {
    if (getAnchorView() == null) {
      return 0;
    }

    int[] anchorViewLocation = new int[2];
    getAnchorView().getLocationOnScreen(anchorViewLocation);
    int anchorViewAbsoluteYTop = anchorViewLocation[1];

    int[] targetParentLocation = new int[2];
    targetParent.getLocationOnScreen(targetParentLocation);
    int targetParentAbsoluteYBottom = targetParentLocation[1] + targetParent.getHeight();

    return targetParentAbsoluteYBottom - anchorViewAbsoluteYTop;
  }

  void animateViewIn() {
    // Post to make sure animation doesn't start until after all inset handling has completed
    view.post(
        new Runnable() {
          @Override
          public void run() {
            if (view == null) {
              return;
            }
            // Make view VISIBLE now that we are about to start the enter animation
            if (view.getParent() != null) {
              view.setVisibility(View.VISIBLE);
            }
            if (view.getAnimationMode() == ANIMATION_MODE_FADE) {
              startFadeInAnimation();
            } else {
              startSlideInAnimation();
            }
          }
        });
  }

  private void animateViewOut(int event) {
    if (view.getAnimationMode() == ANIMATION_MODE_FADE) {
      startFadeOutAnimation(event);
    } else {
      startSlideOutAnimation(event);
    }
  }

  private void startFadeInAnimation() {
    ValueAnimator alphaAnimator = getAlphaAnimator(0, 1);
    ValueAnimator scaleAnimator = getScaleAnimator(ANIMATION_SCALE_FROM_VALUE, 1);

    AnimatorSet animatorSet = new AnimatorSet();
    animatorSet.playTogether(alphaAnimator, scaleAnimator);
    animatorSet.setDuration(ANIMATION_FADE_IN_DURATION);
    animatorSet.addListener(
        new AnimatorListenerAdapter() {
          @Override
          public void onAnimationEnd(Animator animator) {
            onViewShown();
          }
        });
    animatorSet.start();
  }

  private void startFadeOutAnimation(final int event) {
    ValueAnimator animator = getAlphaAnimator(1, 0);
    animator.setDuration(ANIMATION_FADE_OUT_DURATION);
    animator.addListener(
        new AnimatorListenerAdapter() {
          @Override
          public void onAnimationEnd(Animator animator) {
            onViewHidden(event);
          }
        });
    animator.start();
  }

  private ValueAnimator getAlphaAnimator(float... alphaValues) {
    ValueAnimator animator = ValueAnimator.ofFloat(alphaValues);
    animator.setInterpolator(LINEAR_INTERPOLATOR);
    animator.addUpdateListener(
        new AnimatorUpdateListener() {
          @Override
          public void onAnimationUpdate(@NonNull ValueAnimator valueAnimator) {
            view.setAlpha((Float) valueAnimator.getAnimatedValue());
          }
        });
    return animator;
  }

  private ValueAnimator getScaleAnimator(float... scaleValues) {
    ValueAnimator animator = ValueAnimator.ofFloat(scaleValues);
    animator.setInterpolator(LINEAR_OUT_SLOW_IN_INTERPOLATOR);
    animator.addUpdateListener(
        new AnimatorUpdateListener() {
          @Override
          public void onAnimationUpdate(@NonNull ValueAnimator valueAnimator) {
            float scale = (float) valueAnimator.getAnimatedValue();
            view.setScaleX(scale);
            view.setScaleY(scale);
          }
        });
    return animator;
  }

  private void startSlideInAnimation() {
    final int translationYBottom = getTranslationYBottom();
    if (USE_OFFSET_API) {
      ViewCompat.offsetTopAndBottom(view, translationYBottom);
    } else {
      view.setTranslationY(translationYBottom);
    }

    ValueAnimator animator = new ValueAnimator();
    animator.setIntValues(translationYBottom, 0);
    animator.setInterpolator(FAST_OUT_SLOW_IN_INTERPOLATOR);
    animator.setDuration(ANIMATION_DURATION);
    animator.addListener(
        new AnimatorListenerAdapter() {
          @Override
          public void onAnimationStart(Animator animator) {
            contentViewCallback.animateContentIn(
                ANIMATION_DURATION - ANIMATION_FADE_DURATION, ANIMATION_FADE_DURATION);
          }

          @Override
          public void onAnimationEnd(Animator animator) {
            onViewShown();
          }
        });
    animator.addUpdateListener(
        new ValueAnimator.AnimatorUpdateListener() {
          private int previousAnimatedIntValue = translationYBottom;

          @Override
          public void onAnimationUpdate(@NonNull ValueAnimator animator) {
            int currentAnimatedIntValue = (int) animator.getAnimatedValue();
            if (USE_OFFSET_API) {
              // On JB/KK versions of the platform sometimes View.setTranslationY does not
              // result in layout / draw pass
              ViewCompat.offsetTopAndBottom(
                  view, currentAnimatedIntValue - previousAnimatedIntValue);
            } else {
              view.setTranslationY(currentAnimatedIntValue);
            }
            previousAnimatedIntValue = currentAnimatedIntValue;
          }
        });
    animator.start();
  }

  private void startSlideOutAnimation(final int event) {
    ValueAnimator animator = new ValueAnimator();
    animator.setIntValues(0, getTranslationYBottom());
    animator.setInterpolator(FAST_OUT_SLOW_IN_INTERPOLATOR);
    animator.setDuration(ANIMATION_DURATION);
    animator.addListener(
        new AnimatorListenerAdapter() {
          @Override
          public void onAnimationStart(Animator animator) {
            contentViewCallback.animateContentOut(0, ANIMATION_FADE_DURATION);
          }

          @Override
          public void onAnimationEnd(Animator animator) {
            onViewHidden(event);
          }
        });
    animator.addUpdateListener(
        new ValueAnimator.AnimatorUpdateListener() {
          private int previousAnimatedIntValue = 0;

          @Override
          public void onAnimationUpdate(@NonNull ValueAnimator animator) {
            int currentAnimatedIntValue = (int) animator.getAnimatedValue();
            if (USE_OFFSET_API) {
              // On JB/KK versions of the platform sometimes View.setTranslationY does not
              // result in layout / draw pass
              ViewCompat.offsetTopAndBottom(
                  view, currentAnimatedIntValue - previousAnimatedIntValue);
            } else {
              view.setTranslationY(currentAnimatedIntValue);
            }
            previousAnimatedIntValue = currentAnimatedIntValue;
          }
        });
    animator.start();
  }

  private int getTranslationYBottom() {
    int translationY = view.getHeight();
    LayoutParams layoutParams = view.getLayoutParams();
    if (layoutParams instanceof MarginLayoutParams) {
      translationY += ((MarginLayoutParams) layoutParams).bottomMargin;
    }
    return translationY;
  }

  final void hideView(@BaseCallback.DismissEvent int event) {
    if (shouldAnimate() && view.getVisibility() == View.VISIBLE) {
      animateViewOut(event);
    } else {
      // If anims are disabled or the view isn't visible, just call back now
      onViewHidden(event);
    }
  }

  void onViewShown() {
    SnackbarManager.getInstance().onShown(managerCallback);
    if (callbacks != null) {
      // Notify the callbacks. Do that from the end of the list so that if a callback
      // removes itself as the result of being called, it won't mess up with our iteration
      int callbackCount = callbacks.size();
      for (int i = callbackCount - 1; i >= 0; i--) {
        callbacks.get(i).onShown((B) this);
      }
    }
  }

  void onViewHidden(int event) {
    // First tell the SnackbarManager that it has been dismissed
    SnackbarManager.getInstance().onDismissed(managerCallback);
    if (callbacks != null) {
      // Notify the callbacks. Do that from the end of the list so that if a callback
      // removes itself as the result of being called, it won't mess up with our iteration
      int callbackCount = callbacks.size();
      for (int i = callbackCount - 1; i >= 0; i--) {
        callbacks.get(i).onDismissed((B) this, event);
      }
    }

    // Lastly, hide and remove the view from the parent (if attached)
    ViewParent parent = view.getParent();
    if (parent instanceof ViewGroup) {
      ((ViewGroup) parent).removeView(view);
    }
  }

  /** Returns true if we should animate the Snackbar view in/out. */
  boolean shouldAnimate() {
    if (accessibilityManager == null) {
      return true;
    }
    int feedbackFlags = AccessibilityServiceInfo.FEEDBACK_SPOKEN;
    List<AccessibilityServiceInfo> serviceList =
        accessibilityManager.getEnabledAccessibilityServiceList(feedbackFlags);
    return serviceList != null && serviceList.isEmpty();
  }

  /** @hide */
  @RestrictTo(LIBRARY_GROUP)
  protected static class SnackbarBaseLayout extends FrameLayout {
    private static final OnTouchListener consumeAllTouchListener =
        new OnTouchListener() {
          @SuppressLint("ClickableViewAccessibility")
          @Override
          public boolean onTouch(View v, MotionEvent event) {
            // Prevent touches from passing through this view.
            return true;
          }
        };

    @Nullable private BaseTransientBottomBar<?> baseTransientBottomBar;
    @Nullable ShapeAppearanceModel shapeAppearanceModel;
    @AnimationMode private int animationMode;
    private final float backgroundOverlayColorAlpha;
    private final float actionTextColorAlpha;
    private final int maxWidth;
    private final int maxInlineActionWidth;
    private ColorStateList backgroundTint;
    private PorterDuff.Mode backgroundTintMode;

    @Nullable private Rect originalMargins;

    protected SnackbarBaseLayout(@NonNull Context context) {
      this(context, null);
    }

    protected SnackbarBaseLayout(@NonNull Context context, AttributeSet attrs) {
      super(wrap(context, attrs, 0, 0), attrs);
      // Ensure we are using the correctly themed context rather than the context that was passed
      // in.
      context = getContext();
      TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SnackbarLayout);
      if (a.hasValue(R.styleable.SnackbarLayout_elevation)) {
        ViewCompat.setElevation(
            this, a.getDimensionPixelSize(R.styleable.SnackbarLayout_elevation, 0));
      }
      animationMode = a.getInt(R.styleable.SnackbarLayout_animationMode, ANIMATION_MODE_SLIDE);
      if (a.hasValue(R.styleable.SnackbarLayout_shapeAppearance)
          || a.hasValue(R.styleable.SnackbarLayout_shapeAppearanceOverlay)) {
        shapeAppearanceModel =
            ShapeAppearanceModel.builder(
                    context, attrs, /* defStyleAttr= */ 0, /* defStyleRes= */ 0)
                .build();
      }
      backgroundOverlayColorAlpha =
          a.getFloat(R.styleable.SnackbarLayout_backgroundOverlayColorAlpha, 1);
      setBackgroundTintList(
          MaterialResources.getColorStateList(
              context, a, R.styleable.SnackbarLayout_backgroundTint));
      setBackgroundTintMode(
          ViewUtils.parseTintMode(
              a.getInt(R.styleable.SnackbarLayout_backgroundTintMode, -1), PorterDuff.Mode.SRC_IN));
      actionTextColorAlpha = a.getFloat(R.styleable.SnackbarLayout_actionTextColorAlpha, 1);
      maxWidth = a.getDimensionPixelSize(R.styleable.SnackbarLayout_android_maxWidth, -1);
      maxInlineActionWidth =
          a.getDimensionPixelSize(R.styleable.SnackbarLayout_maxActionInlineWidth, -1);
      a.recycle();

      setOnTouchListener(consumeAllTouchListener);
      setFocusable(true);

      if (getBackground() == null) {
        ViewCompat.setBackground(this, createThemedBackground());
      }
    }

    @Override
    public void setBackground(@Nullable Drawable drawable) {
      setBackgroundDrawable(drawable);
    }

    @Override
    public void setBackgroundDrawable(@Nullable Drawable drawable) {
      if (drawable != null && backgroundTint != null) {
        drawable = DrawableCompat.wrap(drawable.mutate());
        DrawableCompat.setTintList(drawable, backgroundTint);
        DrawableCompat.setTintMode(drawable, backgroundTintMode);
      }
      super.setBackgroundDrawable(drawable);
    }

    @Override
    public void setBackgroundTintList(@Nullable ColorStateList backgroundTint) {
      this.backgroundTint = backgroundTint;
      if (getBackground() != null) {
        Drawable wrappedBackground = DrawableCompat.wrap(getBackground().mutate());
        DrawableCompat.setTintList(wrappedBackground, backgroundTint);
        DrawableCompat.setTintMode(wrappedBackground, backgroundTintMode);
        if (wrappedBackground != getBackground()) {
          super.setBackgroundDrawable(wrappedBackground);
        }
      }
    }

    @Override
    public void setBackgroundTintMode(@Nullable PorterDuff.Mode backgroundTintMode) {
      this.backgroundTintMode = backgroundTintMode;
      if (getBackground() != null) {
        Drawable wrappedBackground = DrawableCompat.wrap(getBackground().mutate());
        DrawableCompat.setTintMode(wrappedBackground, backgroundTintMode);
        if (wrappedBackground != getBackground()) {
          super.setBackgroundDrawable(wrappedBackground);
        }
      }
    }

    @Override
    public void setOnClickListener(@Nullable OnClickListener onClickListener) {
      // Clear touch listener that consumes all touches if there is a custom click listener.
      setOnTouchListener(onClickListener != null ? null : consumeAllTouchListener);
      super.setOnClickListener(onClickListener);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
      super.onMeasure(widthMeasureSpec, heightMeasureSpec);
      if (maxWidth > 0 && getMeasuredWidth() > maxWidth) {
        widthMeasureSpec = MeasureSpec.makeMeasureSpec(maxWidth, MeasureSpec.EXACTLY);
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
      }
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
      super.onLayout(changed, l, t, r, b);
      if (baseTransientBottomBar != null) {
        baseTransientBottomBar.onLayoutChange();
      }
    }

    @Override
    protected void onAttachedToWindow() {
      super.onAttachedToWindow();
      if (baseTransientBottomBar != null) {
        baseTransientBottomBar.onAttachedToWindow();
      }
      ViewCompat.requestApplyInsets(this);
    }

    @Override
    protected void onDetachedFromWindow() {
      super.onDetachedFromWindow();
      if (baseTransientBottomBar != null) {
        baseTransientBottomBar.onDetachedFromWindow();
      }
    }

    @Override
    public void setLayoutParams(ViewGroup.LayoutParams params) {
      super.setLayoutParams(params);
      if (params instanceof MarginLayoutParams) {
        updateOriginalMargins((MarginLayoutParams) params);
        if (baseTransientBottomBar != null) {
          baseTransientBottomBar.updateMargins();
        }
      }
    }

    @AnimationMode
    int getAnimationMode() {
      return animationMode;
    }

    void setAnimationMode(@AnimationMode int animationMode) {
      this.animationMode = animationMode;
    }

    float getBackgroundOverlayColorAlpha() {
      return backgroundOverlayColorAlpha;
    }

    float getActionTextColorAlpha() {
      return actionTextColorAlpha;
    }

    int getMaxWidth() {
      return maxWidth;
    }

    int getMaxInlineActionWidth() {
      return maxInlineActionWidth;
    }

    private void setBaseTransientBottomBar(BaseTransientBottomBar<?> baseTransientBottomBar) {
      this.baseTransientBottomBar = baseTransientBottomBar;
    }

    private void updateOriginalMargins(MarginLayoutParams params) {
      originalMargins =
          new Rect(params.leftMargin, params.topMargin, params.rightMargin, params.bottomMargin);
    }

    @NonNull
    private Drawable createThemedBackground() {
      int backgroundColor =
          MaterialColors.layer(
              this, R.attr.colorSurface, R.attr.colorOnSurface, getBackgroundOverlayColorAlpha());
      // Only use newer MaterialShapeDrawable background approach if shape appearance is set, in
      // order to preserve the original GradientDrawable background for pre-M3 Snackbars.
      Drawable background =
          shapeAppearanceModel != null
              ? createMaterialShapeDrawableBackground(backgroundColor, shapeAppearanceModel)
              : createGradientDrawableBackground(backgroundColor, getResources());
      if (backgroundTint != null) {
        Drawable wrappedDrawable = DrawableCompat.wrap(background);
        DrawableCompat.setTintList(wrappedDrawable, backgroundTint);
        return wrappedDrawable;
      } else {
        return DrawableCompat.wrap(background);
      }
    }
  }

  @NonNull
  private static MaterialShapeDrawable createMaterialShapeDrawableBackground(
      @ColorInt int backgroundColor, @NonNull ShapeAppearanceModel shapeAppearanceModel) {
    MaterialShapeDrawable background = new MaterialShapeDrawable(shapeAppearanceModel);
    background.setFillColor(ColorStateList.valueOf(backgroundColor));
    return background;
  }

  @NonNull
  private static GradientDrawable createGradientDrawableBackground(
      @ColorInt int backgroundColor, @NonNull Resources resources) {
    float cornerRadius = resources.getDimension(R.dimen.mtrl_snackbar_background_corner_radius);
    GradientDrawable background = new GradientDrawable();
    background.setShape(GradientDrawable.RECTANGLE);
    background.setCornerRadius(cornerRadius);
    background.setColor(backgroundColor);
    return background;
  }

  /** Behavior for {@link BaseTransientBottomBar}. */
  public static class Behavior extends SwipeDismissBehavior<View> {
    @NonNull private final BehaviorDelegate delegate;

    public Behavior() {
      delegate = new BehaviorDelegate(this);
    }

    private void setBaseTransientBottomBar(
        @NonNull BaseTransientBottomBar<?> baseTransientBottomBar) {
      delegate.setBaseTransientBottomBar(baseTransientBottomBar);
    }

    @Override
    public boolean canSwipeDismissView(View child) {
      return delegate.canSwipeDismissView(child);
    }

    @Override
    public boolean onInterceptTouchEvent(
        @NonNull CoordinatorLayout parent, @NonNull View child, @NonNull MotionEvent event) {
      delegate.onInterceptTouchEvent(parent, child, event);
      return super.onInterceptTouchEvent(parent, child, event);
    }
  }

  /** @hide */
  @RestrictTo(LIBRARY_GROUP)
  // TODO(b/76413401): Delegate can be rolled up into behavior after widget migration is finished.
  public static class BehaviorDelegate {
    private SnackbarManager.Callback managerCallback;

    public BehaviorDelegate(@NonNull SwipeDismissBehavior<?> behavior) {
      behavior.setStartAlphaSwipeDistance(0.1f);
      behavior.setEndAlphaSwipeDistance(0.6f);
      behavior.setSwipeDirection(SwipeDismissBehavior.SWIPE_DIRECTION_START_TO_END);
    }

    public void setBaseTransientBottomBar(
        @NonNull BaseTransientBottomBar<?> baseTransientBottomBar) {
      this.managerCallback = baseTransientBottomBar.managerCallback;
    }

    public boolean canSwipeDismissView(View child) {
      return child instanceof SnackbarBaseLayout;
    }

    public void onInterceptTouchEvent(
        @NonNull CoordinatorLayout parent, @NonNull View child, @NonNull MotionEvent event) {
      switch (event.getActionMasked()) {
        case MotionEvent.ACTION_DOWN:
          // We want to make sure that we disable any Snackbar timeouts if the user is
          // currently touching the Snackbar. We restore the timeout when complete
          if (parent.isPointInChildBounds(child, (int) event.getX(), (int) event.getY())) {
            SnackbarManager.getInstance().pauseTimeout(managerCallback);
          }
          break;
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_CANCEL:
          SnackbarManager.getInstance().restoreTimeoutIfPaused(managerCallback);
          break;
        default:
          break;
      }
    }
  }

  @SuppressWarnings("rawtypes") // Generic type of BaseTransientBottomBar doesn't matter here.
  static class Anchor
      implements android.view.View.OnAttachStateChangeListener, OnGlobalLayoutListener {
    @NonNull
    private final WeakReference<BaseTransientBottomBar> transientBottomBar;

    @NonNull
    private final WeakReference<View> anchorView;

    static Anchor anchor(
        @NonNull BaseTransientBottomBar transientBottomBar, @NonNull View anchorView) {
      Anchor anchor = new Anchor(transientBottomBar, anchorView);
      if (ViewCompat.isAttachedToWindow(anchorView)) {
        ViewUtils.addOnGlobalLayoutListener(anchorView, anchor);
      }
      anchorView.addOnAttachStateChangeListener(anchor);
      return anchor;
    }

    private Anchor(
        @NonNull BaseTransientBottomBar transientBottomBar, @NonNull View anchorView) {
      this.transientBottomBar = new WeakReference<>(transientBottomBar);
      this.anchorView = new WeakReference<>(anchorView);
    }

    @Override
    public void onViewAttachedToWindow(View anchorView) {
      if (unanchorIfNoTransientBottomBar()) {
        return;
      }
      ViewUtils.addOnGlobalLayoutListener(anchorView, this);
    }

    @Override
    public void onViewDetachedFromWindow(View anchorView) {
      if (unanchorIfNoTransientBottomBar()) {
        return;
      }
      ViewUtils.removeOnGlobalLayoutListener(anchorView, this);
    }

    @Override
    public void onGlobalLayout() {
      if (unanchorIfNoTransientBottomBar()
          || !transientBottomBar.get().anchorViewLayoutListenerEnabled) {
        return;
      }
      transientBottomBar.get().recalculateAndUpdateMargins();
    }

    @Nullable
    View getAnchorView() {
      return anchorView.get();
    }

    private boolean unanchorIfNoTransientBottomBar() {
      if (transientBottomBar.get() == null) {
        unanchor();
        return true;
      }
      return false;
    }

    void unanchor() {
      if (anchorView.get() != null) {
        anchorView.get().removeOnAttachStateChangeListener(this);
        ViewUtils.removeOnGlobalLayoutListener(anchorView.get(), this);
      }
      anchorView.clear();
      transientBottomBar.clear();
    }
  }
}