88 lines
2.9 KiB
Java
88 lines
2.9 KiB
Java
/*
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* Copyright (C) 2006 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.text.style;
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import android.text.TextPaint;
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/**
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* The classes that affect character-level text formatting extend this
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* class. Most extend its subclass {@link MetricAffectingSpan}, but simple
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* ones may just implement {@link UpdateAppearance}.
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*/
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public abstract class CharacterStyle {
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public abstract void updateDrawState(TextPaint tp);
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/**
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* A given CharacterStyle can only applied to a single region of a given
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* Spanned. If you need to attach the same CharacterStyle to multiple
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* regions, you can use this method to wrap it with a new object that
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* will have the same effect but be a distinct object so that it can
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* also be attached without conflict.
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*/
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public static CharacterStyle wrap(CharacterStyle cs) {
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if (cs instanceof MetricAffectingSpan) {
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return new MetricAffectingSpan.Passthrough((MetricAffectingSpan) cs);
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} else {
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return new Passthrough(cs);
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}
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}
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/**
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* Returns "this" for most CharacterStyles, but for CharacterStyles
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* that were generated by {@link #wrap}, returns the underlying
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* CharacterStyle.
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*/
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public CharacterStyle getUnderlying() {
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return this;
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}
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/**
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* A Passthrough CharacterStyle is one that
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* passes {@link #updateDrawState} calls through to the
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* specified CharacterStyle while still being a distinct object,
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* and is therefore able to be attached to the same Spannable
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* to which the specified CharacterStyle is already attached.
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*/
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private static class Passthrough extends CharacterStyle {
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private CharacterStyle mStyle;
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/**
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* Creates a new Passthrough of the specfied CharacterStyle.
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*/
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public Passthrough(CharacterStyle cs) {
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mStyle = cs;
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}
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/**
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* Passes updateDrawState through to the underlying CharacterStyle.
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*/
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@Override
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public void updateDrawState(TextPaint tp) {
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mStyle.updateDrawState(tp);
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}
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/**
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* Returns the CharacterStyle underlying this one, or the one
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* underlying it if it too is a Passthrough.
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*/
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@Override
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public CharacterStyle getUnderlying() {
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return mStyle.getUnderlying();
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}
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}
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}
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