135 lines
5.0 KiB
Java
135 lines
5.0 KiB
Java
/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.internal.widget;
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/**
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* An interface that can be implemented by Views to provide scroll related APIs.
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*/
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public interface ScrollingView {
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/**
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* <p>Compute the horizontal range that the horizontal scrollbar
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* represents.</p>
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*
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* <p>The range is expressed in arbitrary units that must be the same as the
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* units used by {@link #computeHorizontalScrollExtent()} and
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* {@link #computeHorizontalScrollOffset()}.</p>
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*
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* <p>The default range is the drawing width of this view.</p>
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*
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* @return the total horizontal range represented by the horizontal
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* scrollbar
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*
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* @see #computeHorizontalScrollExtent()
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* @see #computeHorizontalScrollOffset()
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* @see android.widget.ScrollBarDrawable
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*/
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int computeHorizontalScrollRange();
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/**
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* <p>Compute the horizontal offset of the horizontal scrollbar's thumb
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* within the horizontal range. This value is used to compute the position
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* of the thumb within the scrollbar's track.</p>
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*
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* <p>The range is expressed in arbitrary units that must be the same as the
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* units used by {@link #computeHorizontalScrollRange()} and
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* {@link #computeHorizontalScrollExtent()}.</p>
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*
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* <p>The default offset is the scroll offset of this view.</p>
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*
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* @return the horizontal offset of the scrollbar's thumb
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*
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* @see #computeHorizontalScrollRange()
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* @see #computeHorizontalScrollExtent()
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* @see android.widget.ScrollBarDrawable
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*/
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int computeHorizontalScrollOffset();
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/**
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* <p>Compute the horizontal extent of the horizontal scrollbar's thumb
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* within the horizontal range. This value is used to compute the length
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* of the thumb within the scrollbar's track.</p>
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*
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* <p>The range is expressed in arbitrary units that must be the same as the
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* units used by {@link #computeHorizontalScrollRange()} and
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* {@link #computeHorizontalScrollOffset()}.</p>
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*
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* <p>The default extent is the drawing width of this view.</p>
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*
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* @return the horizontal extent of the scrollbar's thumb
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*
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* @see #computeHorizontalScrollRange()
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* @see #computeHorizontalScrollOffset()
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* @see android.widget.ScrollBarDrawable
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*/
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int computeHorizontalScrollExtent();
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/**
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* <p>Compute the vertical range that the vertical scrollbar represents.</p>
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*
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* <p>The range is expressed in arbitrary units that must be the same as the
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* units used by {@link #computeVerticalScrollExtent()} and
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* {@link #computeVerticalScrollOffset()}.</p>
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*
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* @return the total vertical range represented by the vertical scrollbar
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*
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* <p>The default range is the drawing height of this view.</p>
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*
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* @see #computeVerticalScrollExtent()
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* @see #computeVerticalScrollOffset()
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* @see android.widget.ScrollBarDrawable
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*/
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int computeVerticalScrollRange();
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/**
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* <p>Compute the vertical offset of the vertical scrollbar's thumb
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* within the horizontal range. This value is used to compute the position
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* of the thumb within the scrollbar's track.</p>
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*
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* <p>The range is expressed in arbitrary units that must be the same as the
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* units used by {@link #computeVerticalScrollRange()} and
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* {@link #computeVerticalScrollExtent()}.</p>
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*
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* <p>The default offset is the scroll offset of this view.</p>
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*
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* @return the vertical offset of the scrollbar's thumb
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*
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* @see #computeVerticalScrollRange()
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* @see #computeVerticalScrollExtent()
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* @see android.widget.ScrollBarDrawable
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*/
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int computeVerticalScrollOffset();
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/**
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* <p>Compute the vertical extent of the vertical scrollbar's thumb
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* within the vertical range. This value is used to compute the length
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* of the thumb within the scrollbar's track.</p>
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*
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* <p>The range is expressed in arbitrary units that must be the same as the
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* units used by {@link #computeVerticalScrollRange()} and
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* {@link #computeVerticalScrollOffset()}.</p>
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*
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* <p>The default extent is the drawing height of this view.</p>
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*
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* @return the vertical extent of the scrollbar's thumb
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*
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* @see #computeVerticalScrollRange()
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* @see #computeVerticalScrollOffset()
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* @see android.widget.ScrollBarDrawable
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*/
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int computeVerticalScrollExtent();
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}
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