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/*
* Copyright 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 androidx.widget.recyclerview.selection;
import android.support.annotation.NonNull;
import androidx.widget.recyclerview.selection.SelectionTracker.SelectionPredicate;
/**
* Utility class for creating SelectionPredicate instances. Provides default
* implementations for common cases like "single selection" and "select anything".
*/
public final class SelectionPredicates {
private SelectionPredicates() {}
/**
* Returns a selection predicate that allows multiples items to be selected, without
* any restrictions on which items can be selected.
*
* @param <K> Selection key type. @see {@link StorageStrategy} for supported types.
* @return
*/
public static <K> SelectionPredicate<K> createSelectAnything() {
return new SelectionPredicate<K>() {
@Override
public boolean canSetStateForKey(@NonNull K key, boolean nextState) {
return true;
}
@Override
public boolean canSetStateAtPosition(int position, boolean nextState) {
return true;
}
@Override
public boolean canSelectMultiple() {
return true;
}
};
}
/**
* Returns a selection predicate that allows a single item to be selected, without
* any restrictions on which item can be selected.
*
* @param <K> Selection key type. @see {@link StorageStrategy} for supported types.
* @return
*/
public static <K> SelectionPredicate<K> createSelectSingleAnything() {
return new SelectionPredicate<K>() {
@Override
public boolean canSetStateForKey(@NonNull K key, boolean nextState) {
return true;
}
@Override
public boolean canSetStateAtPosition(int position, boolean nextState) {
return true;
}
@Override
public boolean canSelectMultiple() {
return false;
}
};
}
}
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