quickstep/src/com/android/quickstep/util/MultiValueUpdateListener.java


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/*
 * Copyright (C) 2018 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.android.quickstep.util;

import android.animation.ValueAnimator;
import android.view.animation.Interpolator;

import java.util.ArrayList;

/**
 * Utility class to update multiple values with different interpolators and durations during
 * the same animation.
 */
public abstract class MultiValueUpdateListener implements ValueAnimator.AnimatorUpdateListener {

    private final ArrayList<FloatProp> mAllProperties = new ArrayList<>();

    @Override
    public final void onAnimationUpdate(ValueAnimator animator) {
        final float percent = animator.getAnimatedFraction();
        final float currentPlayTime = percent * animator.getDuration();

        for (int i = mAllProperties.size() - 1; i >= 0; i--) {
            FloatProp prop = mAllProperties.get(i);
            float time = Math.max(0, currentPlayTime - prop.mDelay);
            float newPercent = Math.min(1f, time / prop.mDuration);
            newPercent = prop.mInterpolator.getInterpolation(newPercent);
            prop.value = prop.mEnd * newPercent + prop.mStart * (1 - newPercent);
        }
        onUpdate(percent);
    }

    public abstract void onUpdate(float percent);

    public final class FloatProp {

        public float value;

        private final float mStart;
        private final float mEnd;
        private final float mDelay;
        private final float mDuration;
        private final Interpolator mInterpolator;

        public FloatProp(float start, float end, float delay, float duration, Interpolator i) {
            value = mStart = start;
            mEnd = end;
            mDelay = delay;
            mDuration = duration;
            mInterpolator = i;

            mAllProperties.add(this);
        }
    }
}