| /* |
| * 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.animation; |
| |
| /** |
| * Abstract base class used convert type T to another type V and back again. This |
| * is necessary when the value types of in animation are different from the property |
| * type. BidirectionalTypeConverter is needed when only the final value for the |
| * animation is supplied to animators. |
| * @see PropertyValuesHolder#setConverter(TypeConverter) |
| */ |
| public abstract class BidirectionalTypeConverter<T, V> extends TypeConverter<T, V> { |
| private BidirectionalTypeConverter mInvertedConverter; |
| |
| public BidirectionalTypeConverter(Class<T> fromClass, Class<V> toClass) { |
| super(fromClass, toClass); |
| } |
| |
| /** |
| * Does a conversion from the target type back to the source type. The subclass |
| * must implement this when a TypeConverter is used in animations and current |
| * values will need to be read for an animation. |
| * @param value The Object to convert. |
| * @return A value of type T, converted from <code>value</code>. |
| */ |
| public abstract T convertBack(V value); |
| |
| /** |
| * Returns the inverse of this converter, where the from and to classes are reversed. |
| * The inverted converter uses this convert to call {@link #convertBack(Object)} for |
| * {@link #convert(Object)} calls and {@link #convert(Object)} for |
| * {@link #convertBack(Object)} calls. |
| * @return The inverse of this converter, where the from and to classes are reversed. |
| */ |
| public BidirectionalTypeConverter<V, T> invert() { |
| if (mInvertedConverter == null) { |
| mInvertedConverter = new InvertedConverter(this); |
| } |
| return mInvertedConverter; |
| } |
| |
| private static class InvertedConverter<From, To> extends BidirectionalTypeConverter<From, To> { |
| private BidirectionalTypeConverter<To, From> mConverter; |
| |
| public InvertedConverter(BidirectionalTypeConverter<To, From> converter) { |
| super(converter.getTargetType(), converter.getSourceType()); |
| mConverter = converter; |
| } |
| |
| @Override |
| public From convertBack(To value) { |
| return mConverter.convert(value); |
| } |
| |
| @Override |
| public To convert(From value) { |
| return mConverter.convertBack(value); |
| } |
| } |
| } |