content: /*
   * Copyright (C) 2018 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.android.launcher3.settings;
  
  import static com.android.launcher3.icons.GraphicsUtils.setColorAlphaBound;
  
  import android.animation.Animator;
  import android.animation.AnimatorListenerAdapter;
  import android.animation.ObjectAnimator;
  import android.animation.ValueAnimator;
  import android.graphics.Canvas;
  import android.graphics.Color;
  import android.graphics.Paint;
  import android.util.Property;
  import android.view.View;
  
  import com.android.launcher3.util.Themes;
  
  import androidx.recyclerview.widget.RecyclerView;
  import androidx.recyclerview.widget.RecyclerView.ItemDecoration;
  import androidx.recyclerview.widget.RecyclerView.State;
  import androidx.recyclerview.widget.RecyclerView.ViewHolder;
  
  /**
   * Utility class for highlighting a preference
   */
  public class PreferenceHighlighter extends ItemDecoration implements Runnable {
  
      private static final Property<PreferenceHighlighter, Integer> HIGHLIGHT_COLOR =
              new Property<PreferenceHighlighter, Integer>(Integer.TYPE, "highlightColor") {
  
                  @Override
                  public Integer get(PreferenceHighlighter highlighter) {
                      return highlighter.mHighlightColor;
                  }
  
                  @Override
                  public void set(PreferenceHighlighter highlighter, Integer value) {
                      highlighter.mHighlightColor = value;
                      highlighter.mRv.invalidateItemDecorations();
                  }
              };
  
      private static final long HIGHLIGHT_DURATION = 15000L;
      private static final long HIGHLIGHT_FADE_OUT_DURATION = 500L;
      private static final long HIGHLIGHT_FADE_IN_DURATION = 200L;
      private static final int END_COLOR = setColorAlphaBound(Color.WHITE, 0);
  
      private final Paint mPaint = new Paint();
      private final RecyclerView mRv;
      private final int mIndex;
  
      private boolean mHighLightStarted = false;
      private int mHighlightColor = END_COLOR;
  
  
      public PreferenceHighlighter(RecyclerView rv, int index) {
          mRv = rv;
          mIndex = index;
      }
  
      @Override
      public void run() {
          mRv.addItemDecoration(this);
          mRv.smoothScrollToPosition(mIndex);
      }
  
      @Override
      public void onDraw(Canvas c, RecyclerView parent, State state) {
          ViewHolder holder = parent.findViewHolderForAdapterPosition(mIndex);
          if (holder == null) {
              return;
          }
          if (!mHighLightStarted && state.getRemainingScrollVertical() != 0) {
              // Wait until scrolling stopped
              return;
          }
  
          if (!mHighLightStarted) {
              // Start highlight
              int colorTo = setColorAlphaBound(Themes.getColorAccent(mRv.getContext()), 66);
              ObjectAnimator anim = ObjectAnimator.ofArgb(this, HIGHLIGHT_COLOR, END_COLOR, colorTo);
              anim.setDuration(HIGHLIGHT_FADE_IN_DURATION);
              anim.setRepeatMode(ValueAnimator.REVERSE);
              anim.setRepeatCount(4);
              anim.addListener(new AnimatorListenerAdapter() {
                  @Override
                  public void onAnimationEnd(Animator animation) {
                      removeHighlight();
                  }
              });
              anim.start();
              mHighLightStarted = true;
          }
  
          View view = holder.itemView;
          mPaint.setColor(mHighlightColor);
          c.drawRect(0, view.getY(), parent.getWidth(), view.getY() + view.getHeight(), mPaint);
      }
  
      private void removeHighlight() {
          ObjectAnimator anim = ObjectAnimator.ofArgb(
                  this, HIGHLIGHT_COLOR, mHighlightColor, END_COLOR);
          anim.setDuration(HIGHLIGHT_FADE_OUT_DURATION);
          anim.setStartDelay(HIGHLIGHT_DURATION);
          anim.addListener(new AnimatorListenerAdapter() {
              @Override
              public void onAnimationEnd(Animator animation) {
                  mRv.removeItemDecoration(PreferenceHighlighter.this);
              }
          });
          anim.start();
      }
  }
  