| /* |
| * Copyright (C) 2016 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.support.v17.leanback.widget; |
| |
| import android.animation.ObjectAnimator; |
| import android.animation.PropertyValuesHolder; |
| import android.view.animation.LinearInterpolator; |
| |
| /** |
| * ParallaxTarget is responsible for updating the target through the {@link #update(float)} method. |
| * {@link ParallaxEffect} transforms the values of {@link Parallax}, which represents the |
| * current state of UI, into a float value between 0 and 1. That float value is passed into |
| * {@link #update(float)} method. |
| */ |
| public abstract class ParallaxTarget { |
| |
| /** |
| * Implementation class is supposed to update target with the provided fraction |
| * (between 0 and 1). The fraction represents percentage of completed change (e.g. scroll) on |
| * target. |
| * |
| * @param fraction Fraction between 0 to 1. |
| */ |
| public abstract void update(float fraction); |
| |
| /** |
| * Returns the current fraction (between 0 and 1). The fraction represents percentage of |
| * completed change (e.g. scroll) on target. |
| * |
| * @return Current fraction value. |
| */ |
| public abstract float getFraction(); |
| |
| /** |
| * PropertyValuesHolderTarget is an implementation of {@link ParallaxTarget} that uses |
| * {@link PropertyValuesHolder} to update the target object. |
| */ |
| public static final class PropertyValuesHolderTarget extends ParallaxTarget { |
| |
| /** |
| * We simulate a parallax effect on target object using an ObjectAnimator. PSEUDO_DURATION |
| * is used on the ObjectAnimator. |
| */ |
| private static final long PSEUDO_DURATION = 1000000; |
| |
| private final ObjectAnimator mAnimator; |
| private float mFraction; |
| |
| public PropertyValuesHolderTarget(Object targetObject, PropertyValuesHolder values) { |
| mAnimator = ObjectAnimator.ofPropertyValuesHolder(targetObject, values); |
| mAnimator.setInterpolator(new LinearInterpolator()); |
| mAnimator.setDuration(PSEUDO_DURATION); |
| } |
| |
| @Override |
| public void update(float fraction) { |
| mFraction = fraction; |
| mAnimator.setCurrentPlayTime((long) (PSEUDO_DURATION * fraction)); |
| } |
| |
| @Override |
| public float getFraction() { |
| return mFraction; |
| } |
| } |
| } |