1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package android.animation; 17 18 import java.util.ArrayList; 19 20 /** 21 * This interface abstracts a collection of Keyframe objects and is called by 22 * ValueAnimator to calculate values between those keyframes for a given animation. 23 */ 24 interface Keyframes extends Cloneable { 25 26 /** 27 * Sets the TypeEvaluator to be used when calculating animated values. This object 28 * is required only for Keyframes that are not either IntKeyframes or FloatKeyframes, 29 * both of which assume their own evaluator to speed up calculations with those primitive 30 * types. 31 * 32 * @param evaluator The TypeEvaluator to be used to calculate animated values. 33 */ setEvaluator(TypeEvaluator evaluator)34 void setEvaluator(TypeEvaluator evaluator); 35 36 /** 37 * @return The value type contained by the contained Keyframes. 38 */ getType()39 Class getType(); 40 41 /** 42 * Gets the animated value, given the elapsed fraction of the animation (interpolated by the 43 * animation's interpolator) and the evaluator used to calculate in-between values. This 44 * function maps the input fraction to the appropriate keyframe interval and a fraction 45 * between them and returns the interpolated value. Note that the input fraction may fall 46 * outside the [0-1] bounds, if the animation's interpolator made that happen (e.g., a 47 * spring interpolation that might send the fraction past 1.0). We handle this situation by 48 * just using the two keyframes at the appropriate end when the value is outside those bounds. 49 * 50 * @param fraction The elapsed fraction of the animation 51 * @return The animated value. 52 */ getValue(float fraction)53 Object getValue(float fraction); 54 55 /** 56 * If subclass has variables that it calculates based on the Keyframes, it should reset them 57 * when this method is called because Keyframe contents might have changed. 58 */ invalidateCache()59 void invalidateCache(); 60 61 /** 62 * @return A list of all Keyframes contained by this. This may return null if this is 63 * not made up of Keyframes. 64 */ getKeyframes()65 ArrayList<Keyframe> getKeyframes(); 66 clone()67 Keyframes clone(); 68 69 /** 70 * A specialization of Keyframes that has integer primitive value calculation. 71 */ 72 public interface IntKeyframes extends Keyframes { 73 74 /** 75 * Works like {@link #getValue(float)}, but returning a primitive. 76 * @param fraction The elapsed fraction of the animation 77 * @return The animated value. 78 */ getIntValue(float fraction)79 int getIntValue(float fraction); 80 } 81 82 /** 83 * A specialization of Keyframes that has float primitive value calculation. 84 */ 85 public interface FloatKeyframes extends Keyframes { 86 87 /** 88 * Works like {@link #getValue(float)}, but returning a primitive. 89 * @param fraction The elapsed fraction of the animation 90 * @return The animated value. 91 */ getFloatValue(float fraction)92 float getFloatValue(float fraction); 93 } 94 } 95