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/*
* Copyright (C) 2014 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 android.content.res;
import android.content.pm.ActivityInfo.Config;
/**
* A cache class that can provide new instances of a particular resource which may change
* depending on the current {@link Resources.Theme} or {@link Configuration}.
* <p>
* A constant state should be able to return a bitmask of changing configurations, which
* identifies the type of configuration changes that may invalidate this resource. These
* configuration changes can be obtained from {@link android.util.TypedValue}. Entities such as
* {@link android.animation.Animator} also provide a changing configuration method to include
* their dependencies (e.g. An AnimatorSet's changing configuration is the union of the
* changing configurations of each Animator in the set)
* @hide
*/
abstract public class ConstantState<T> {
/**
* Return a bit mask of configuration changes that will impact
* this resource (and thus require completely reloading it).
*/
abstract public @Config int getChangingConfigurations();
/**
* Create a new instance without supplying resources the caller
* is running in.
*/
public abstract T newInstance();
/**
* Create a new instance from its constant state. This
* must be implemented for resources that change based on the target
* density of their caller (that is depending on whether it is
* in compatibility mode).
*/
public T newInstance(Resources res) {
return newInstance();
}
/**
* Create a new instance from its constant state. This must be
* implemented for resources that can have a theme applied.
*/
public T newInstance(Resources res, Resources.Theme theme) {
return newInstance(res);
}
}
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