Java tutorial
/* 50AH-code ========= 50 Android Hacks (http://manning.com/sessa/) book source code Copyright (c) 2012 Manning Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /* * Copyright (C) 2010 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 com.actionbarsherlock.internal.nineoldandroids.animation; import java.util.ArrayList; import java.util.Arrays; import android.view.animation.Interpolator; import com.actionbarsherlock.internal.nineoldandroids.animation.Keyframe.FloatKeyframe; import com.actionbarsherlock.internal.nineoldandroids.animation.Keyframe.IntKeyframe; import com.actionbarsherlock.internal.nineoldandroids.animation.Keyframe.ObjectKeyframe; /** * This class holds a collection of Keyframe objects and is called by ValueAnimator to calculate * values between those keyframes for a given animation. The class internal to the animation * package because it is an implementation detail of how Keyframes are stored and used. */ @SuppressWarnings({ "rawtypes", "unchecked" }) class KeyframeSet { int mNumKeyframes; Keyframe mFirstKeyframe; Keyframe mLastKeyframe; /*Time*/Interpolator mInterpolator; // only used in the 2-keyframe case ArrayList<Keyframe> mKeyframes; // only used when there are not 2 keyframes TypeEvaluator mEvaluator; public KeyframeSet(Keyframe... keyframes) { mNumKeyframes = keyframes.length; mKeyframes = new ArrayList<Keyframe>(); mKeyframes.addAll(Arrays.asList(keyframes)); mFirstKeyframe = mKeyframes.get(0); mLastKeyframe = mKeyframes.get(mNumKeyframes - 1); mInterpolator = mLastKeyframe.getInterpolator(); } public static KeyframeSet ofInt(int... values) { int numKeyframes = values.length; IntKeyframe keyframes[] = new IntKeyframe[Math.max(numKeyframes, 2)]; if (numKeyframes == 1) { keyframes[0] = (IntKeyframe) Keyframe.ofInt(0f); keyframes[1] = (IntKeyframe) Keyframe.ofInt(1f, values[0]); } else { keyframes[0] = (IntKeyframe) Keyframe.ofInt(0f, values[0]); for (int i = 1; i < numKeyframes; ++i) { keyframes[i] = (IntKeyframe) Keyframe.ofInt((float) i / (numKeyframes - 1), values[i]); } } return new IntKeyframeSet(keyframes); } public static KeyframeSet ofFloat(float... values) { int numKeyframes = values.length; FloatKeyframe keyframes[] = new FloatKeyframe[Math.max(numKeyframes, 2)]; if (numKeyframes == 1) { keyframes[0] = (FloatKeyframe) Keyframe.ofFloat(0f); keyframes[1] = (FloatKeyframe) Keyframe.ofFloat(1f, values[0]); } else { keyframes[0] = (FloatKeyframe) Keyframe.ofFloat(0f, values[0]); for (int i = 1; i < numKeyframes; ++i) { keyframes[i] = (FloatKeyframe) Keyframe.ofFloat((float) i / (numKeyframes - 1), values[i]); } } return new FloatKeyframeSet(keyframes); } public static KeyframeSet ofKeyframe(Keyframe... keyframes) { // if all keyframes of same primitive type, create the appropriate KeyframeSet int numKeyframes = keyframes.length; boolean hasFloat = false; boolean hasInt = false; boolean hasOther = false; for (int i = 0; i < numKeyframes; ++i) { if (keyframes[i] instanceof FloatKeyframe) { hasFloat = true; } else if (keyframes[i] instanceof IntKeyframe) { hasInt = true; } else { hasOther = true; } } if (hasFloat && !hasInt && !hasOther) { FloatKeyframe floatKeyframes[] = new FloatKeyframe[numKeyframes]; for (int i = 0; i < numKeyframes; ++i) { floatKeyframes[i] = (FloatKeyframe) keyframes[i]; } return new FloatKeyframeSet(floatKeyframes); } else if (hasInt && !hasFloat && !hasOther) { IntKeyframe intKeyframes[] = new IntKeyframe[numKeyframes]; for (int i = 0; i < numKeyframes; ++i) { intKeyframes[i] = (IntKeyframe) keyframes[i]; } return new IntKeyframeSet(intKeyframes); } else { return new KeyframeSet(keyframes); } } public static KeyframeSet ofObject(Object... values) { int numKeyframes = values.length; ObjectKeyframe keyframes[] = new ObjectKeyframe[Math.max(numKeyframes, 2)]; if (numKeyframes == 1) { keyframes[0] = (ObjectKeyframe) Keyframe.ofObject(0f); keyframes[1] = (ObjectKeyframe) Keyframe.ofObject(1f, values[0]); } else { keyframes[0] = (ObjectKeyframe) Keyframe.ofObject(0f, values[0]); for (int i = 1; i < numKeyframes; ++i) { keyframes[i] = (ObjectKeyframe) Keyframe.ofObject((float) i / (numKeyframes - 1), values[i]); } } return new KeyframeSet(keyframes); } /** * Sets the TypeEvaluator to be used when calculating animated values. This object * is required only for KeyframeSets that are not either IntKeyframeSet or FloatKeyframeSet, * both of which assume their own evaluator to speed up calculations with those primitive * types. * * @param evaluator The TypeEvaluator to be used to calculate animated values. */ public void setEvaluator(TypeEvaluator evaluator) { mEvaluator = evaluator; } @Override public KeyframeSet clone() { ArrayList<Keyframe> keyframes = mKeyframes; int numKeyframes = mKeyframes.size(); Keyframe[] newKeyframes = new Keyframe[numKeyframes]; for (int i = 0; i < numKeyframes; ++i) { newKeyframes[i] = keyframes.get(i).clone(); } KeyframeSet newSet = new KeyframeSet(newKeyframes); return newSet; } /** * Gets the animated value, given the elapsed fraction of the animation (interpolated by the * animation's interpolator) and the evaluator used to calculate in-between values. This * function maps the input fraction to the appropriate keyframe interval and a fraction * between them and returns the interpolated value. Note that the input fraction may fall * outside the [0-1] bounds, if the animation's interpolator made that happen (e.g., a * spring interpolation that might send the fraction past 1.0). We handle this situation by * just using the two keyframes at the appropriate end when the value is outside those bounds. * * @param fraction The elapsed fraction of the animation * @return The animated value. */ public Object getValue(float fraction) { // Special-case optimization for the common case of only two keyframes if (mNumKeyframes == 2) { if (mInterpolator != null) { fraction = mInterpolator.getInterpolation(fraction); } return mEvaluator.evaluate(fraction, mFirstKeyframe.getValue(), mLastKeyframe.getValue()); } if (fraction <= 0f) { final Keyframe nextKeyframe = mKeyframes.get(1); final /*Time*/Interpolator interpolator = nextKeyframe.getInterpolator(); if (interpolator != null) { fraction = interpolator.getInterpolation(fraction); } final float prevFraction = mFirstKeyframe.getFraction(); float intervalFraction = (fraction - prevFraction) / (nextKeyframe.getFraction() - prevFraction); return mEvaluator.evaluate(intervalFraction, mFirstKeyframe.getValue(), nextKeyframe.getValue()); } else if (fraction >= 1f) { final Keyframe prevKeyframe = mKeyframes.get(mNumKeyframes - 2); final /*Time*/Interpolator interpolator = mLastKeyframe.getInterpolator(); if (interpolator != null) { fraction = interpolator.getInterpolation(fraction); } final float prevFraction = prevKeyframe.getFraction(); float intervalFraction = (fraction - prevFraction) / (mLastKeyframe.getFraction() - prevFraction); return mEvaluator.evaluate(intervalFraction, prevKeyframe.getValue(), mLastKeyframe.getValue()); } Keyframe prevKeyframe = mFirstKeyframe; for (int i = 1; i < mNumKeyframes; ++i) { Keyframe nextKeyframe = mKeyframes.get(i); if (fraction < nextKeyframe.getFraction()) { final /*Time*/Interpolator interpolator = nextKeyframe.getInterpolator(); if (interpolator != null) { fraction = interpolator.getInterpolation(fraction); } final float prevFraction = prevKeyframe.getFraction(); float intervalFraction = (fraction - prevFraction) / (nextKeyframe.getFraction() - prevFraction); return mEvaluator.evaluate(intervalFraction, prevKeyframe.getValue(), nextKeyframe.getValue()); } prevKeyframe = nextKeyframe; } // shouldn't reach here return mLastKeyframe.getValue(); } @Override public String toString() { String returnVal = " "; for (int i = 0; i < mNumKeyframes; ++i) { returnVal += mKeyframes.get(i).getValue() + " "; } return returnVal; } }