/*
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* Copyright (C) 2010 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.launcher3.util;
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import static com.android.launcher3.anim.Interpolators.SCROLL;
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import android.animation.TimeInterpolator;
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import android.content.Context;
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import android.hardware.SensorManager;
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import android.util.Log;
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import android.view.ViewConfiguration;
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import android.view.animation.AnimationUtils;
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import android.view.animation.Interpolator;
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import androidx.dynamicanimation.animation.DynamicAnimation;
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import androidx.dynamicanimation.animation.FloatPropertyCompat;
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import androidx.dynamicanimation.animation.SpringAnimation;
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import androidx.dynamicanimation.animation.SpringForce;
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/**
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* Based on {@link android.widget.OverScroller} supporting only 1-d scrolling and with more
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* customization options.
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*/
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public class OverScroller {
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private int mMode;
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private final SplineOverScroller mScroller;
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private TimeInterpolator mInterpolator;
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private final boolean mFlywheel;
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private static final int DEFAULT_DURATION = 250;
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private static final int SCROLL_MODE = 0;
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private static final int FLING_MODE = 1;
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/**
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* Creates an OverScroller with a viscous fluid scroll interpolator and flywheel.
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* @param context
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*/
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public OverScroller(Context context) {
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this(context, null);
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}
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/**
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* Creates an OverScroller with flywheel enabled.
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* @param context The context of this application.
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* @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will
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* be used.
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*/
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public OverScroller(Context context, Interpolator interpolator) {
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this(context, interpolator, true);
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}
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/**
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* Creates an OverScroller.
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* @param context The context of this application.
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* @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will
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* be used.
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* @param flywheel If true, successive fling motions will keep on increasing scroll speed.
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*/
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public OverScroller(Context context, Interpolator interpolator, boolean flywheel) {
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if (interpolator == null) {
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mInterpolator = SCROLL;
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} else {
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mInterpolator = interpolator;
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}
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mFlywheel = flywheel;
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mScroller = new SplineOverScroller(context);
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}
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public void setInterpolator(TimeInterpolator interpolator) {
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if (interpolator == null) {
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mInterpolator = SCROLL;
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} else {
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mInterpolator = interpolator;
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}
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}
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/**
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* The amount of friction applied to flings. The default value
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* is {@link ViewConfiguration#getScrollFriction}.
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*
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* @param friction A scalar dimension-less value representing the coefficient of
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* friction.
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*/
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public final void setFriction(float friction) {
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mScroller.setFriction(friction);
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}
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/**
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*
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* Returns whether the scroller has finished scrolling.
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*
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* @return True if the scroller has finished scrolling, false otherwise.
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*/
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public final boolean isFinished() {
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return mScroller.mFinished;
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}
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/**
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* Force the finished field to a particular value. Contrary to
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* {@link #abortAnimation()}, forcing the animation to finished
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* does NOT cause the scroller to move to the final x and y
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* position.
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*
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* @param finished The new finished value.
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*/
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public final void forceFinished(boolean finished) {
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mScroller.mFinished = finished;
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}
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/**
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* Returns the current offset in the scroll.
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*
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* @return The new offset as an absolute distance from the origin.
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*/
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public final int getCurrPos() {
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return mScroller.mCurrentPosition;
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}
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/**
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* Returns the absolute value of the current velocity.
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*
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* @return The original velocity less the deceleration, norm of the X and Y velocity vector.
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*/
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public float getCurrVelocity() {
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return mScroller.mCurrVelocity;
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}
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/**
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* Returns the start offset in the scroll.
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*
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* @return The start offset as an absolute distance from the origin.
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*/
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public final int getStartPos() {
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return mScroller.mStart;
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}
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/**
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* Returns where the scroll will end. Valid only for "fling" scrolls.
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*
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* @return The final offset as an absolute distance from the origin.
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*/
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public final int getFinalPos() {
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return mScroller.mFinal;
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}
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/**
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* Returns how long the scroll event will take, in milliseconds.
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*
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* @return The duration of the scroll in milliseconds.
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*/
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public final int getDuration() {
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return mScroller.mDuration;
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}
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/**
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* Extend the scroll animation. This allows a running animation to scroll
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* further and longer, when used with {@link #setFinalPos(int)}.
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*
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* @param extend Additional time to scroll in milliseconds.
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* @see #setFinalPos(int)
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*/
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public void extendDuration(int extend) {
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mScroller.extendDuration(extend);
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}
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/**
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* Sets the final position for this scroller.
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*
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* @param newPos The new offset as an absolute distance from the origin.
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* @see #extendDuration(int)
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*/
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public void setFinalPos(int newPos) {
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mScroller.setFinalPosition(newPos);
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}
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/**
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* Call this when you want to know the new location. If it returns true, the
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* animation is not yet finished.
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*/
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public boolean computeScrollOffset() {
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if (isFinished()) {
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return false;
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}
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switch (mMode) {
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case SCROLL_MODE:
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if (isSpringing()) {
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return true;
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}
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long time = AnimationUtils.currentAnimationTimeMillis();
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// Any scroller can be used for time, since they were started
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// together in scroll mode. We use X here.
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final long elapsedTime = time - mScroller.mStartTime;
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final int duration = mScroller.mDuration;
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if (elapsedTime < duration) {
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final float q = mInterpolator.getInterpolation(elapsedTime / (float) duration);
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mScroller.updateScroll(q);
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} else {
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abortAnimation();
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}
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break;
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case FLING_MODE:
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if (!mScroller.mFinished) {
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if (!mScroller.update()) {
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if (!mScroller.continueWhenFinished()) {
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mScroller.finish();
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}
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}
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}
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break;
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}
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return true;
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}
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/**
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* Start scrolling by providing a starting point and the distance to travel.
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* The scroll will use the default value of 250 milliseconds for the
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* duration.
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*
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* @param start Starting horizontal scroll offset in pixels. Positive
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* numbers will scroll the content to the left.
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* @param delta Distance to travel. Positive numbers will scroll the
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* content to the left.
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*/
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public void startScroll(int start, int delta) {
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startScroll(start, delta, DEFAULT_DURATION);
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}
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/**
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* Start scrolling by providing a starting point and the distance to travel.
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*
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* @param start Starting scroll offset in pixels. Positive
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* numbers will scroll the content to the left.
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* @param delta Distance to travel. Positive numbers will scroll the
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* content to the left.
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* @param duration Duration of the scroll in milliseconds.
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*/
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public void startScroll(int start, int delta, int duration) {
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mMode = SCROLL_MODE;
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mScroller.startScroll(start, delta, duration);
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}
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/**
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* Start scrolling using a spring by providing a starting point and the distance to travel.
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*
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* @param start Starting scroll offset in pixels. Positive
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* numbers will scroll the content to the left.
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* @param delta Distance to travel. Positive numbers will scroll the
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* content to the left.
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* @param duration Duration of the scroll in milliseconds.
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* @param velocity The starting velocity for the spring in px per ms.
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*/
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public void startScrollSpring(int start, int delta, int duration, float velocity) {
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mMode = SCROLL_MODE;
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mScroller.mState = mScroller.SPRING;
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mScroller.startScroll(start, delta, duration, velocity);
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}
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/**
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* Call this when you want to 'spring back' into a valid coordinate range.
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*
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* @param start Starting X coordinate
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* @param min Minimum valid X value
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* @param max Maximum valid X value
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* @return true if a springback was initiated, false if startX and startY were
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* already within the valid range.
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*/
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public boolean springBack(int start, int min, int max) {
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mMode = FLING_MODE;
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return mScroller.springback(start, min, max);
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}
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public void fling(int start, int velocity, int min, int max) {
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fling(start, velocity, min, max, 0);
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}
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/**
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* Start scrolling based on a fling gesture. The distance traveled will
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* depend on the initial velocity of the fling.
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* @param start Starting point of the scroll (X)
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* @param velocity Initial velocity of the fling (X) measured in pixels per
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* second.
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* @param min Minimum X value. The scroller will not scroll past this point
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* unless overX > 0. If overfling is allowed, it will use minX as
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* a springback boundary.
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* @param max Maximum X value. The scroller will not scroll past this point
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* unless overX > 0. If overfling is allowed, it will use maxX as
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* a springback boundary.
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* @param over Overfling range. If > 0, horizontal overfling in either
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* direction will be possible.
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*/
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public void fling(int start, int velocity, int min, int max, int over) {
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// Continue a scroll or fling in progress
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if (mFlywheel && !isFinished()) {
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float oldVelocityX = mScroller.mCurrVelocity;
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if (Math.signum(velocity) == Math.signum(oldVelocityX)) {
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velocity += oldVelocityX;
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}
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}
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mMode = FLING_MODE;
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mScroller.fling(start, velocity, min, max, over);
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}
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/**
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* Notify the scroller that we've reached a horizontal boundary.
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* Normally the information to handle this will already be known
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* when the animation is started, such as in a call to one of the
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* fling functions. However there are cases where this cannot be known
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* in advance. This function will transition the current motion and
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* animate from startX to finalX as appropriate.
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* @param start Starting/current X position
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* @param finalPos Desired final X position
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* @param over Magnitude of overscroll allowed. This should be the maximum
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*/
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public void notifyEdgeReached(int start, int finalPos, int over) {
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mScroller.notifyEdgeReached(start, finalPos, over);
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}
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/**
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* Returns whether the current Scroller is currently returning to a valid position.
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* Valid bounds were provided by the
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* {@link #fling(int, int, int, int, int)} method.
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*
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* One should check this value before calling
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* {@link #startScroll(int, int)} as the interpolation currently in progress
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* to restore a valid position will then be stopped. The caller has to take into account
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* the fact that the started scroll will start from an overscrolled position.
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*
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* @return true when the current position is overscrolled and in the process of
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* interpolating back to a valid value.
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*/
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public boolean isOverScrolled() {
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return (!mScroller.mFinished && mScroller.mState != SplineOverScroller.SPLINE);
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}
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/**
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* Stops the animation. Contrary to {@link #forceFinished(boolean)},
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* aborting the animating causes the scroller to move to the final x and y
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* positions.
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*
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* @see #forceFinished(boolean)
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*/
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public void abortAnimation() {
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mScroller.finish();
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}
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/**
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* Returns the time elapsed since the beginning of the scrolling.
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*
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* @return The elapsed time in milliseconds.
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*
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* @hide
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*/
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public int timePassed() {
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final long time = AnimationUtils.currentAnimationTimeMillis();
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return (int) (time - mScroller.mStartTime);
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}
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public boolean isSpringing() {
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return mScroller.mState == SplineOverScroller.SPRING && !isFinished();
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}
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static class SplineOverScroller {
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// Initial position
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private int mStart;
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// Current position
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private int mCurrentPosition;
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// Final position
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private int mFinal;
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// Initial velocity
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private int mVelocity;
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// Current velocity
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private float mCurrVelocity;
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// Constant current deceleration
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private float mDeceleration;
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// Animation starting time, in system milliseconds
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private long mStartTime;
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// Animation duration, in milliseconds
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private int mDuration;
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// Duration to complete spline component of animation
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private int mSplineDuration;
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// Distance to travel along spline animation
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private int mSplineDistance;
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// Whether the animation is currently in progress
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private boolean mFinished;
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// The allowed overshot distance before boundary is reached.
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private int mOver;
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// Fling friction
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private float mFlingFriction = ViewConfiguration.getScrollFriction();
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// Current state of the animation.
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private int mState = SPLINE;
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private SpringAnimation mSpring;
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// Constant gravity value, used in the deceleration phase.
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private static final float GRAVITY = 2000.0f;
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// A context-specific coefficient adjusted to physical values.
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private float mPhysicalCoeff;
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private static float DECELERATION_RATE = (float) (Math.log(0.78) / Math.log(0.9));
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private static final float INFLEXION = 0.35f; // Tension lines cross at (INFLEXION, 1)
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private static final float START_TENSION = 0.5f;
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private static final float END_TENSION = 1.0f;
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private static final float P1 = START_TENSION * INFLEXION;
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private static final float P2 = 1.0f - END_TENSION * (1.0f - INFLEXION);
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private static final int NB_SAMPLES = 100;
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private static final float[] SPLINE_POSITION = new float[NB_SAMPLES + 1];
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private static final float[] SPLINE_TIME = new float[NB_SAMPLES + 1];
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private static final int SPLINE = 0;
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private static final int CUBIC = 1;
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private static final int BALLISTIC = 2;
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private static final int SPRING = 3;
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private static final FloatPropertyCompat<SplineOverScroller> SPRING_PROPERTY =
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new FloatPropertyCompat<SplineOverScroller>("splineOverScrollerSpring") {
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@Override
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public float getValue(SplineOverScroller scroller) {
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return scroller.mCurrentPosition;
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}
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@Override
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public void setValue(SplineOverScroller scroller, float value) {
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scroller.mCurrentPosition = (int) value;
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}
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};
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static {
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float x_min = 0.0f;
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float y_min = 0.0f;
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for (int i = 0; i < NB_SAMPLES; i++) {
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final float alpha = (float) i / NB_SAMPLES;
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float x_max = 1.0f;
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float x, tx, coef;
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while (true) {
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x = x_min + (x_max - x_min) / 2.0f;
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coef = 3.0f * x * (1.0f - x);
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tx = coef * ((1.0f - x) * P1 + x * P2) + x * x * x;
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if (Math.abs(tx - alpha) < 1E-5) break;
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if (tx > alpha) x_max = x;
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else x_min = x;
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}
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SPLINE_POSITION[i] = coef * ((1.0f - x) * START_TENSION + x) + x * x * x;
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float y_max = 1.0f;
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float y, dy;
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while (true) {
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y = y_min + (y_max - y_min) / 2.0f;
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coef = 3.0f * y * (1.0f - y);
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dy = coef * ((1.0f - y) * START_TENSION + y) + y * y * y;
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if (Math.abs(dy - alpha) < 1E-5) break;
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if (dy > alpha) y_max = y;
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else y_min = y;
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}
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SPLINE_TIME[i] = coef * ((1.0f - y) * P1 + y * P2) + y * y * y;
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}
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SPLINE_POSITION[NB_SAMPLES] = SPLINE_TIME[NB_SAMPLES] = 1.0f;
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}
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void setFriction(float friction) {
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mFlingFriction = friction;
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}
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SplineOverScroller(Context context) {
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mFinished = true;
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final float ppi = context.getResources().getDisplayMetrics().density * 160.0f;
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mPhysicalCoeff = SensorManager.GRAVITY_EARTH // g (m/s^2)
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* 39.37f // inch/meter
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* ppi
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* 0.84f; // look and feel tuning
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}
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void updateScroll(float q) {
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if (mState == SPRING) {
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return;
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}
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/*AW_CODE;fix currentposition change not smooth;jiangbin;200305 */
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//mCurrentPosition = mStart + Math.round(q * (mFinal - mStart));
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int tmpCurrenPostion = mStart + Math.round(q * (mFinal - mStart));
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boolean isIncreasePosition = mFinal > mStart? true:false;
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if((isIncreasePosition && (tmpCurrenPostion > mCurrentPosition))
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||(!isIncreasePosition &&(tmpCurrenPostion < mCurrentPosition))) {
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mCurrentPosition = tmpCurrenPostion;
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} else {
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if((q != 1.0f) && (mCurrentPosition!= mFinal)) {
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int threshold = mFinal > mStart? 1:-1;
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mCurrentPosition+=threshold;
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}
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}
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/*end*/
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}
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/*
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* Get a signed deceleration that will reduce the velocity.
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*/
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static private float getDeceleration(int velocity) {
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return velocity > 0 ? -GRAVITY : GRAVITY;
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}
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/*
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* Modifies mDuration to the duration it takes to get from start to newFinal using the
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* spline interpolation. The previous duration was needed to get to oldFinal.
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*/
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private void adjustDuration(int start, int oldFinal, int newFinal) {
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final int oldDistance = oldFinal - start;
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final int newDistance = newFinal - start;
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final float x = Math.abs((float) newDistance / oldDistance);
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final int index = (int) (NB_SAMPLES * x);
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if (index < NB_SAMPLES) {
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final float x_inf = (float) index / NB_SAMPLES;
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final float x_sup = (float) (index + 1) / NB_SAMPLES;
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final float t_inf = SPLINE_TIME[index];
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final float t_sup = SPLINE_TIME[index + 1];
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final float timeCoef = t_inf + (x - x_inf) / (x_sup - x_inf) * (t_sup - t_inf);
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mDuration *= timeCoef;
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}
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}
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void startScroll(int start, int distance, int duration) {
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startScroll(start, distance, duration, 0);
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}
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void startScroll(int start, int distance, int duration, float velocity) {
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mFinished = false;
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mCurrentPosition = mStart = start;
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mFinal = start + distance;
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mStartTime = AnimationUtils.currentAnimationTimeMillis();
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mDuration = duration;
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if (mState == SPRING) {
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if (mSpring != null) {
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mSpring.cancel();
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}
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mSpring = new SpringAnimation(this, SPRING_PROPERTY);
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mSpring.setSpring(new SpringForce(mFinal)
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.setStiffness(SpringForce.STIFFNESS_LOW)
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.setDampingRatio(SpringForce.DAMPING_RATIO_LOW_BOUNCY));
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mSpring.setStartVelocity(velocity);
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mSpring.animateToFinalPosition(mFinal);
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mSpring.addEndListener((animation, canceled, value, velocity1) -> {
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finish();
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mState = SPLINE;
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mSpring = null;
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});
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}
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// Unused
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mDeceleration = 0.0f;
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mVelocity = 0;
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}
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void finish() {
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if (mSpring != null && mSpring.isRunning()) mSpring.cancel();
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mCurrentPosition = mFinal;
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// Not reset since WebView relies on this value for fast fling.
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// TODO: restore when WebView uses the fast fling implemented in this class.
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// mCurrVelocity = 0.0f;
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mFinished = true;
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}
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void setFinalPosition(int position) {
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mFinal = position;
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if (mState == SPRING && mSpring != null) {
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mSpring.animateToFinalPosition(mFinal);
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}
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mSplineDistance = mFinal - mStart;
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mFinished = false;
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}
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void extendDuration(int extend) {
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final long time = AnimationUtils.currentAnimationTimeMillis();
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final int elapsedTime = (int) (time - mStartTime);
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mDuration = mSplineDuration = elapsedTime + extend;
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mFinished = false;
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}
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boolean springback(int start, int min, int max) {
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mFinished = true;
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mCurrentPosition = mStart = mFinal = start;
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mVelocity = 0;
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mStartTime = AnimationUtils.currentAnimationTimeMillis();
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mDuration = 0;
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if (start < min) {
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startSpringback(start, min, 0);
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} else if (start > max) {
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startSpringback(start, max, 0);
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}
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return !mFinished;
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}
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private void startSpringback(int start, int end, int velocity) {
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// mStartTime has been set
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mFinished = false;
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mState = CUBIC;
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mCurrentPosition = mStart = start;
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mFinal = end;
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final int delta = start - end;
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mDeceleration = getDeceleration(delta);
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// TODO take velocity into account
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mVelocity = -delta; // only sign is used
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mOver = Math.abs(delta);
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mDuration = (int) (1000.0 * Math.sqrt(-2.0 * delta / mDeceleration));
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}
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void fling(int start, int velocity, int min, int max, int over) {
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mOver = over;
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mFinished = false;
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mCurrVelocity = mVelocity = velocity;
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mDuration = mSplineDuration = 0;
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mStartTime = AnimationUtils.currentAnimationTimeMillis();
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mCurrentPosition = mStart = start;
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if (start > max || start < min) {
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startAfterEdge(start, min, max, velocity);
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return;
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}
|
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mState = SPLINE;
|
double totalDistance = 0.0;
|
|
if (velocity != 0) {
|
mDuration = mSplineDuration = getSplineFlingDuration(velocity);
|
totalDistance = getSplineFlingDistance(velocity);
|
}
|
|
mSplineDistance = (int) (totalDistance * Math.signum(velocity));
|
mFinal = start + mSplineDistance;
|
|
// Clamp to a valid final position
|
if (mFinal < min) {
|
adjustDuration(mStart, mFinal, min);
|
mFinal = min;
|
}
|
|
if (mFinal > max) {
|
adjustDuration(mStart, mFinal, max);
|
mFinal = max;
|
}
|
}
|
|
private double getSplineDeceleration(int velocity) {
|
return Math.log(INFLEXION * Math.abs(velocity) / (mFlingFriction * mPhysicalCoeff));
|
}
|
|
private double getSplineFlingDistance(int velocity) {
|
final double l = getSplineDeceleration(velocity);
|
final double decelMinusOne = DECELERATION_RATE - 1.0;
|
return mFlingFriction * mPhysicalCoeff * Math.exp(DECELERATION_RATE / decelMinusOne * l);
|
}
|
|
/* Returns the duration, expressed in milliseconds */
|
private int getSplineFlingDuration(int velocity) {
|
final double l = getSplineDeceleration(velocity);
|
final double decelMinusOne = DECELERATION_RATE - 1.0;
|
return (int) (1000.0 * Math.exp(l / decelMinusOne));
|
}
|
|
private void fitOnBounceCurve(int start, int end, int velocity) {
|
// Simulate a bounce that started from edge
|
final float durationToApex = - velocity / mDeceleration;
|
// The float cast below is necessary to avoid integer overflow.
|
final float velocitySquared = (float) velocity * velocity;
|
final float distanceToApex = velocitySquared / 2.0f / Math.abs(mDeceleration);
|
final float distanceToEdge = Math.abs(end - start);
|
final float totalDuration = (float) Math.sqrt(
|
2.0 * (distanceToApex + distanceToEdge) / Math.abs(mDeceleration));
|
mStartTime -= (int) (1000.0f * (totalDuration - durationToApex));
|
mCurrentPosition = mStart = end;
|
mVelocity = (int) (- mDeceleration * totalDuration);
|
}
|
|
private void startBounceAfterEdge(int start, int end, int velocity) {
|
mDeceleration = getDeceleration(velocity == 0 ? start - end : velocity);
|
fitOnBounceCurve(start, end, velocity);
|
onEdgeReached();
|
}
|
|
private void startAfterEdge(int start, int min, int max, int velocity) {
|
if (start > min && start < max) {
|
Log.e("OverScroller", "startAfterEdge called from a valid position");
|
mFinished = true;
|
return;
|
}
|
final boolean positive = start > max;
|
final int edge = positive ? max : min;
|
final int overDistance = start - edge;
|
boolean keepIncreasing = overDistance * velocity >= 0;
|
if (keepIncreasing) {
|
// Will result in a bounce or a to_boundary depending on velocity.
|
startBounceAfterEdge(start, edge, velocity);
|
} else {
|
final double totalDistance = getSplineFlingDistance(velocity);
|
if (totalDistance > Math.abs(overDistance)) {
|
fling(start, velocity, positive ? min : start, positive ? start : max, mOver);
|
} else {
|
startSpringback(start, edge, velocity);
|
}
|
}
|
}
|
|
void notifyEdgeReached(int start, int end, int over) {
|
// mState is used to detect successive notifications
|
if (mState == SPLINE) {
|
mOver = over;
|
mStartTime = AnimationUtils.currentAnimationTimeMillis();
|
// We were in fling/scroll mode before: current velocity is such that distance to
|
// edge is increasing. This ensures that startAfterEdge will not start a new fling.
|
startAfterEdge(start, end, end, (int) mCurrVelocity);
|
}
|
}
|
|
private void onEdgeReached() {
|
// mStart, mVelocity and mStartTime were adjusted to their values when edge was reached.
|
// The float cast below is necessary to avoid integer overflow.
|
final float velocitySquared = (float) mVelocity * mVelocity;
|
float distance = velocitySquared / (2.0f * Math.abs(mDeceleration));
|
final float sign = Math.signum(mVelocity);
|
|
if (distance > mOver) {
|
// Default deceleration is not sufficient to slow us down before boundary
|
mDeceleration = - sign * velocitySquared / (2.0f * mOver);
|
distance = mOver;
|
}
|
|
mOver = (int) distance;
|
mState = BALLISTIC;
|
mFinal = mStart + (int) (mVelocity > 0 ? distance : -distance);
|
mDuration = - (int) (1000.0f * mVelocity / mDeceleration);
|
}
|
|
boolean continueWhenFinished() {
|
switch (mState) {
|
case SPLINE:
|
// Duration from start to null velocity
|
if (mDuration < mSplineDuration) {
|
// If the animation was clamped, we reached the edge
|
mCurrentPosition = mStart = mFinal;
|
// TODO Better compute speed when edge was reached
|
mVelocity = (int) mCurrVelocity;
|
mDeceleration = getDeceleration(mVelocity);
|
mStartTime += mDuration;
|
onEdgeReached();
|
} else {
|
// Normal stop, no need to continue
|
return false;
|
}
|
break;
|
case BALLISTIC:
|
mStartTime += mDuration;
|
startSpringback(mFinal, mStart, 0);
|
break;
|
case CUBIC:
|
return false;
|
}
|
|
update();
|
return true;
|
}
|
|
/*
|
* Update the current position and velocity for current time. Returns
|
* true if update has been done and false if animation duration has been
|
* reached.
|
*/
|
boolean update() {
|
if (mState == SPRING) {
|
return mFinished;
|
}
|
|
final long time = AnimationUtils.currentAnimationTimeMillis();
|
final long currentTime = time - mStartTime;
|
|
if (currentTime == 0) {
|
// Skip work but report that we're still going if we have a nonzero duration.
|
return mDuration > 0;
|
}
|
if (currentTime > mDuration) {
|
return false;
|
}
|
|
double distance = 0.0;
|
switch (mState) {
|
case SPLINE: {
|
final float t = (float) currentTime / mSplineDuration;
|
final int index = (int) (NB_SAMPLES * t);
|
float distanceCoef = 1.f;
|
float velocityCoef = 0.f;
|
if (index < NB_SAMPLES) {
|
final float t_inf = (float) index / NB_SAMPLES;
|
final float t_sup = (float) (index + 1) / NB_SAMPLES;
|
final float d_inf = SPLINE_POSITION[index];
|
final float d_sup = SPLINE_POSITION[index + 1];
|
velocityCoef = (d_sup - d_inf) / (t_sup - t_inf);
|
distanceCoef = d_inf + (t - t_inf) * velocityCoef;
|
}
|
|
distance = distanceCoef * mSplineDistance;
|
mCurrVelocity = velocityCoef * mSplineDistance / mSplineDuration * 1000.0f;
|
break;
|
}
|
|
case BALLISTIC: {
|
final float t = currentTime / 1000.0f;
|
mCurrVelocity = mVelocity + mDeceleration * t;
|
distance = mVelocity * t + mDeceleration * t * t / 2.0f;
|
break;
|
}
|
|
case CUBIC: {
|
final float t = (float) (currentTime) / mDuration;
|
final float t2 = t * t;
|
final float sign = Math.signum(mVelocity);
|
distance = sign * mOver * (3.0f * t2 - 2.0f * t * t2);
|
mCurrVelocity = sign * mOver * 6.0f * (- t + t2);
|
break;
|
}
|
}
|
|
mCurrentPosition = mStart + (int) Math.round(distance);
|
|
return true;
|
}
|
}
|
}
|
