content: /*
   * Copyright 2019 Google LLC
   *
   * 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
   *
   *     https://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 me.zhanghai.android.fastscroll;
  
  import android.view.View;
  import android.view.animation.Interpolator;
  
  import androidx.annotation.NonNull;
  import androidx.interpolator.view.animation.FastOutLinearInInterpolator;
  import androidx.interpolator.view.animation.LinearOutSlowInInterpolator;
  
  public class DefaultAnimationHelper implements FastScroller.AnimationHelper {
  
      private static final int SHOW_DURATION_MILLIS = 150;
      private static final int HIDE_DURATION_MILLIS = 200;
      private static final Interpolator SHOW_SCROLLBAR_INTERPOLATOR =
              new LinearOutSlowInInterpolator();
      private static final Interpolator HIDE_SCROLLBAR_INTERPOLATOR =
              new FastOutLinearInInterpolator();
      private static final int AUTO_HIDE_SCROLLBAR_DELAY_MILLIS = 1500;
  
      @NonNull
      private final View mView;
  
      private boolean mScrollbarAutoHideEnabled = true;
  
      private boolean mShowingScrollbar = true;
      private boolean mShowingPopup;
  
      public DefaultAnimationHelper(@NonNull View view) {
          mView = view;
      }
  
      @Override
      public void showScrollbar(@NonNull View trackView, @NonNull View thumbView) {
  
          if (mShowingScrollbar) {
              return;
          }
          mShowingScrollbar = true;
  
          trackView.animate()
                  .alpha(1)
                  .translationX(0)
                  .setDuration(SHOW_DURATION_MILLIS)
                  .setInterpolator(SHOW_SCROLLBAR_INTERPOLATOR)
                  .start();
          thumbView.animate()
                  .alpha(1)
                  .translationX(0)
                  .setDuration(SHOW_DURATION_MILLIS)
                  .setInterpolator(SHOW_SCROLLBAR_INTERPOLATOR)
                  .start();
      }
  
      @Override
      public void hideScrollbar(@NonNull View trackView, @NonNull View thumbView) {
  
          if (!mShowingScrollbar) {
              return;
          }
          mShowingScrollbar = false;
  
          boolean isLayoutRtl = mView.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL;
          int width = Math.max(trackView.getWidth(), thumbView.getWidth());
          float translationX;
          if (isLayoutRtl) {
              translationX = trackView.getLeft() == 0 ? -width : 0;
          } else {
              translationX = trackView.getRight() == mView.getWidth() ? width : 0;
          }
          trackView.animate()
                  .alpha(0)
                  .translationX(translationX)
                  .setDuration(HIDE_DURATION_MILLIS)
                  .setInterpolator(HIDE_SCROLLBAR_INTERPOLATOR)
                  .start();
          thumbView.animate()
                  .alpha(0)
                  .translationX(translationX)
                  .setDuration(HIDE_DURATION_MILLIS)
                  .setInterpolator(HIDE_SCROLLBAR_INTERPOLATOR)
                  .start();
      }
  
      @Override
      public boolean isScrollbarAutoHideEnabled() {
          return mScrollbarAutoHideEnabled;
      }
  
      public void setScrollbarAutoHideEnabled(boolean enabled) {
          mScrollbarAutoHideEnabled = enabled;
      }
  
      @Override
      public int getScrollbarAutoHideDelayMillis() {
          return AUTO_HIDE_SCROLLBAR_DELAY_MILLIS;
      }
  
      @Override
      public void showPopup(@NonNull View popupView) {
  
          if (mShowingPopup) {
              return;
          }
          mShowingPopup = true;
  
          popupView.animate()
                  .alpha(1)
                  .setDuration(SHOW_DURATION_MILLIS)
                  .start();
      }
  
      @Override
      public void hidePopup(@NonNull View popupView) {
  
          if (!mShowingPopup) {
              return;
          }
          mShowingPopup = false;
  
          popupView.animate()
                  .alpha(0)
                  .setDuration(HIDE_DURATION_MILLIS)
                  .start();
      }
  }
  