mirror of https://github.com/M66B/FairEmail.git
88 lines
2.7 KiB
Java
88 lines
2.7 KiB
Java
/*
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* Copyright 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 androidx.recyclerview.selection;
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import androidx.annotation.NonNull;
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import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
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import androidx.recyclerview.widget.RecyclerView;
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/**
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* Override methods in this class to provide application specific behaviors
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* related to focusing item.
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*
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* @param <K> Selection key type. @see {@link StorageStrategy} for supported types.
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*/
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public abstract class FocusDelegate<K> {
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static <K> FocusDelegate<K> dummy() {
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return new FocusDelegate<K>() {
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@Override
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public void focusItem(@NonNull ItemDetails<K> item) {
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}
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@Override
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public boolean hasFocusedItem() {
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return false;
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}
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@Override
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public int getFocusedPosition() {
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return RecyclerView.NO_POSITION;
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}
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@Override
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public void clearFocus() {
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}
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};
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}
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/**
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* If environment supports focus, focus {@code item}.
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*/
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public abstract void focusItem(@NonNull ItemDetails<K> item);
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/**
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* @return true if there is a focused item.
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*/
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public abstract boolean hasFocusedItem();
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/**
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* Returns the position of the currently focused item, or
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* {@link RecyclerView#NO_POSITION} if nothing is focused.
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*
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* <p>You must implement this feature if you intend your app
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* to work well with mouse and keyboard. Selection
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* ranges are inferred from focused item when there is
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* no explicit last-selected item.
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*
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* <p>You can manage and advance focus using keyboard arrows,
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* reflecting this state visibly in the view item.
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* Use can then press shift, then click another item with
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* their mouse to select all items between the focused
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* item and the clicked item.
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*
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* @return the position of the currently focused item,
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* or {@code RecyclerView#NO_POSITION} if none.
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*/
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public abstract int getFocusedPosition();
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/**
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* If the environment supports focus and something is focused, unfocus it.
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*/
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public abstract void clearFocus();
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}
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