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