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