content: /*
   * Copyright (C) 2017 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.internal.widget;
  
  /**
   * An interface that can be implemented by Views to provide scroll related APIs.
   */
  public interface ScrollingView {
      /**
       * <p>Compute the horizontal range that the horizontal scrollbar
       * represents.</p>
       *
       * <p>The range is expressed in arbitrary units that must be the same as the
       * units used by {@link #computeHorizontalScrollExtent()} and
       * {@link #computeHorizontalScrollOffset()}.</p>
       *
       * <p>The default range is the drawing width of this view.</p>
       *
       * @return the total horizontal range represented by the horizontal
       *         scrollbar
       *
       * @see #computeHorizontalScrollExtent()
       * @see #computeHorizontalScrollOffset()
       * @see android.widget.ScrollBarDrawable
       */
      int computeHorizontalScrollRange();
  
      /**
       * <p>Compute the horizontal offset of the horizontal scrollbar's thumb
       * within the horizontal range. This value is used to compute the position
       * of the thumb within the scrollbar's track.</p>
       *
       * <p>The range is expressed in arbitrary units that must be the same as the
       * units used by {@link #computeHorizontalScrollRange()} and
       * {@link #computeHorizontalScrollExtent()}.</p>
       *
       * <p>The default offset is the scroll offset of this view.</p>
       *
       * @return the horizontal offset of the scrollbar's thumb
       *
       * @see #computeHorizontalScrollRange()
       * @see #computeHorizontalScrollExtent()
       * @see android.widget.ScrollBarDrawable
       */
      int computeHorizontalScrollOffset();
  
      /**
       * <p>Compute the horizontal extent of the horizontal scrollbar's thumb
       * within the horizontal range. This value is used to compute the length
       * of the thumb within the scrollbar's track.</p>
       *
       * <p>The range is expressed in arbitrary units that must be the same as the
       * units used by {@link #computeHorizontalScrollRange()} and
       * {@link #computeHorizontalScrollOffset()}.</p>
       *
       * <p>The default extent is the drawing width of this view.</p>
       *
       * @return the horizontal extent of the scrollbar's thumb
       *
       * @see #computeHorizontalScrollRange()
       * @see #computeHorizontalScrollOffset()
       * @see android.widget.ScrollBarDrawable
       */
      int computeHorizontalScrollExtent();
  
      /**
       * <p>Compute the vertical range that the vertical scrollbar represents.</p>
       *
       * <p>The range is expressed in arbitrary units that must be the same as the
       * units used by {@link #computeVerticalScrollExtent()} and
       * {@link #computeVerticalScrollOffset()}.</p>
       *
       * @return the total vertical range represented by the vertical scrollbar
       *
       * <p>The default range is the drawing height of this view.</p>
       *
       * @see #computeVerticalScrollExtent()
       * @see #computeVerticalScrollOffset()
       * @see android.widget.ScrollBarDrawable
       */
      int computeVerticalScrollRange();
  
      /**
       * <p>Compute the vertical offset of the vertical scrollbar's thumb
       * within the horizontal range. This value is used to compute the position
       * of the thumb within the scrollbar's track.</p>
       *
       * <p>The range is expressed in arbitrary units that must be the same as the
       * units used by {@link #computeVerticalScrollRange()} and
       * {@link #computeVerticalScrollExtent()}.</p>
       *
       * <p>The default offset is the scroll offset of this view.</p>
       *
       * @return the vertical offset of the scrollbar's thumb
       *
       * @see #computeVerticalScrollRange()
       * @see #computeVerticalScrollExtent()
       * @see android.widget.ScrollBarDrawable
       */
      int computeVerticalScrollOffset();
  
      /**
       * <p>Compute the vertical extent of the vertical scrollbar's thumb
       * within the vertical range. This value is used to compute the length
       * of the thumb within the scrollbar's track.</p>
       *
       * <p>The range is expressed in arbitrary units that must be the same as the
       * units used by {@link #computeVerticalScrollRange()} and
       * {@link #computeVerticalScrollOffset()}.</p>
       *
       * <p>The default extent is the drawing height of this view.</p>
       *
       * @return the vertical extent of the scrollbar's thumb
       *
       * @see #computeVerticalScrollRange()
       * @see #computeVerticalScrollOffset()
       * @see android.widget.ScrollBarDrawable
       */
      int computeVerticalScrollExtent();
  }
  