53 lines
2.2 KiB
Java
53 lines
2.2 KiB
Java
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/*
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* Copyright (C) 2008 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 android.widget;
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/**
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* Interface that should be implemented on Adapters to enable fast scrolling
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* in an {@link AbsListView} between sections of the list. A section is a group of list items
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* to jump to that have something in common. For example, they may begin with the
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* same letter or they may be songs from the same artist.
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*/
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public interface SectionIndexer {
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/**
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* This provides the list view with an array of section objects. In the simplest
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* case these are Strings, each containing one letter of the alphabet.
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* They could be more complex objects that indicate the grouping for the adapter's
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* consumption. The list view will call toString() on the objects to get the
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* preview letter to display while scrolling.
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* @return the array of objects that indicate the different sections of the list.
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*/
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Object[] getSections();
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/**
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* Provides the starting index in the list for a given section.
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* @param section the index of the section to jump to.
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* @return the starting position of that section. If the section is out of bounds, the
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* position must be clipped to fall within the size of the list.
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*/
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int getPositionForSection(int section);
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/**
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* This is a reverse mapping to fetch the section index for a given position
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* in the list.
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* @param position the position for which to return the section
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* @return the section index. If the position is out of bounds, the section index
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* must be clipped to fall within the size of the section array.
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*/
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int getSectionForPosition(int position);
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}
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