89 lines
3.6 KiB
Java
89 lines
3.6 KiB
Java
/*
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* Copyright (C) 2015 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.setupwizardlib.items;
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/**
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* Representation of zero or more items in a list. Each instance of ItemHierarchy should be capable
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* of being wrapped in ItemAdapter and be displayed.
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*
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* <p>For example, {@link com.android.setupwizardlib.items.Item} is a representation of a single
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* item, typically with data provided from XML. {@link com.android.setupwizardlib.items.ItemGroup}
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* represents a list of child item hierarchies it contains, but itself does not do any display.
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*/
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public interface ItemHierarchy {
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/**
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* Observer for any changes in this hierarchy. If anything updated that causes this hierarchy to
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* show different content, this observer should be called.
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*/
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interface Observer {
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/**
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* Called when an underlying data update that can cause this hierarchy to show different content
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* has occurred.
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*
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* <p>Note: This is a catch-all notification, but recycler view will have a harder time figuring
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* out the animations for the change, and might even not animate the change at all.
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*/
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void onChanged(ItemHierarchy itemHierarchy);
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/**
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* Called when an underlying data update that can cause changes that are local to the given
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* items. This method indicates that there are no structural changes like inserting or removing
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* items.
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*/
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void onItemRangeChanged(ItemHierarchy itemHierarchy, int positionStart, int itemCount);
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/** Called when items are inserted at the given position. */
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void onItemRangeInserted(ItemHierarchy itemHierarchy, int positionStart, int itemCount);
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/** Called when the given items are moved to a different position. */
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void onItemRangeMoved(
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ItemHierarchy itemHierarchy, int fromPosition, int toPosition, int itemCount);
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/** Called when the given items are removed from the item hierarchy. */
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void onItemRangeRemoved(ItemHierarchy itemHierarchy, int positionStart, int itemCount);
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}
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/** Register an observer to observe changes for this item hierarchy. */
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void registerObserver(Observer observer);
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/** Unregister a previously registered observer. */
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void unregisterObserver(Observer observer);
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/** @return the number of items this item hierarchy represent. */
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int getCount();
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/**
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* Get the item at position.
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*
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* @param position An integer from 0 to {@link #getCount()}}, which indicates the position in this
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* item hierarchy to get the child item.
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* @return A representation of the item at {@code position}. Must not be {@code null}.
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*/
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IItem getItemAt(int position);
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/**
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* Find an item hierarchy within this hierarchy which has the given ID. Or null if no match is
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* found. This hierarchy will be returned if our ID matches. Same restrictions for Android
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* resource IDs apply to this ID. In fact, typically this ID is a resource ID generated from XML.
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*
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* @param id An ID to search for in this item hierarchy.
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* @return An ItemHierarchy which matches the given ID.
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*/
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ItemHierarchy findItemById(int id);
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}
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