Added OverScroller and overscroll effects for ScrollView and HorizontalScrollView. (17dfce15) · Commits · e / os / android_frameworks_base

core/java/android/widget/HorizontalScrollView.java

+19 −33

Original line number	Diff line number	Diff line
		@@ -63,7 +63,7 @@ public class HorizontalScrollView extends FrameLayout {
		private long mLastScroll;

		private final Rect mTempRect = new Rect();
		private Scroller mScroller;
		private OverScroller mScroller;

		/**
		* Flag to indicate that we are moving focus ourselves. This is so the
		@@ -177,7 +177,7 @@ public class HorizontalScrollView extends FrameLayout {


		private void initScrollView() {
		mScroller = new Scroller(getContext());
		mScroller = new OverScroller(getContext());
		setFocusable(true);
		setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
		setWillNotDraw(false);
		@@ -380,11 +380,6 @@ public class HorizontalScrollView extends FrameLayout {
		return true;
		}

		if (!canScroll()) {
		mIsBeingDragged = false;
		return false;
		}

		final float x = ev.getX();

		switch (action) {
		@@ -440,10 +435,6 @@ public class HorizontalScrollView extends FrameLayout {
		return false;
		}

		if (!canScroll()) {
		return false;
		}

		if (mVelocityTracker == null) {
		mVelocityTracker = VelocityTracker.obtain();
		}
		@@ -470,25 +461,23 @@ public class HorizontalScrollView extends FrameLayout {
		final int deltaX = (int) (mLastMotionX - x);
		mLastMotionX = x;

		if (deltaX < 0) {
		if (mScrollX > 0) {
		scrollBy(deltaX, 0);
		}
		} else if (deltaX > 0) {
		final int rightEdge = getWidth() - mPaddingRight;
		final int availableToScroll = getChildAt(0).getRight() - mScrollX - rightEdge;
		if (availableToScroll > 0) {
		scrollBy(Math.min(availableToScroll, deltaX), 0);
		}
		}
		super.scrollTo(mScrollX + deltaX, mScrollY);
		break;
		case MotionEvent.ACTION_UP:
		final VelocityTracker velocityTracker = mVelocityTracker;
		velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
		int initialVelocity = (int) velocityTracker.getXVelocity();

		if ((Math.abs(initialVelocity) > mMinimumVelocity) && getChildCount() > 0) {
		if (getChildCount() > 0) {
		if ((Math.abs(initialVelocity) > mMinimumVelocity)) {
		fling(-initialVelocity);
		} else {
		final int right = Math.max(0, getChildAt(0).getHeight() -
		(getHeight() - mPaddingRight - mPaddingLeft));
		if (mScroller.springback(mScrollX, mScrollY, 0, 0, right, 0)) {
		invalidate();
		}
		}
		}

		if (mVelocityTracker != null) {
		@@ -913,14 +902,10 @@ public class HorizontalScrollView extends FrameLayout {
		int oldY = mScrollY;
		int x = mScroller.getCurrX();
		int y = mScroller.getCurrY();
		if (getChildCount() > 0) {
		View child = getChildAt(0);
		mScrollX = clamp(x, getWidth() - mPaddingRight - mPaddingLeft, child.getWidth());
		mScrollY = clamp(y, getHeight() - mPaddingBottom - mPaddingTop, child.getHeight());
		} else {

		mScrollX = x;
		mScrollY = y;
		}

		if (oldX != mScrollX \|\| oldY != mScrollY) {
		onScrollChanged(mScrollX, mScrollY, oldX, oldY);
		}
		@@ -1156,7 +1141,8 @@ public class HorizontalScrollView extends FrameLayout {
		int width = getWidth() - mPaddingRight - mPaddingLeft;
		int right = getChildAt(0).getWidth();

		mScroller.fling(mScrollX, mScrollY, velocityX, 0, 0, right - width, 0, 0);
		mScroller.fling(mScrollX, mScrollY, velocityX, 0, 0,
		Math.max(0, right - width), 0, 0, width/2, 0);

		final boolean movingRight = velocityX > 0;

core/java/android/widget/OverScroller.java

0 → 100644

+354 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2006 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.widget;

		import android.content.Context;
		import android.view.animation.AccelerateDecelerateInterpolator;
		import android.view.animation.DecelerateInterpolator;

		/**
		* This class encapsulates scrolling with the ability to overshoot the bounds
		* of a scrolling operation. This class attempts to be a drop-in replacement
		* for {@link android.widget.Scroller} in most cases.
		*
		* @hide Pending API approval
		*/
		public class OverScroller {
		private static final int SPRINGBACK_DURATION = 150;
		private static final int OVERFLING_DURATION = 150;

		private static final int MODE_DEFAULT = 0;
		private static final int MODE_OVERFLING = 1;
		private static final int MODE_SPRINGBACK = 2;

		private Scroller mDefaultScroller;
		private Scroller mDecelScroller;
		private Scroller mAccelDecelScroller;
		private Scroller mCurrScroller;

		private int mScrollMode = MODE_DEFAULT;

		private int mMinimumX;
		private int mMinimumY;
		private int mMaximumX;
		private int mMaximumY;

		public OverScroller(Context context) {
		mDefaultScroller = new Scroller(context);
		mDecelScroller = new Scroller(context, new DecelerateInterpolator(3.f));
		mAccelDecelScroller = new Scroller(context, new AccelerateDecelerateInterpolator());
		mCurrScroller = mDefaultScroller;
		}

		/**
		* Call this when you want to know the new location. If it returns true,
		* the animation is not yet finished. loc will be altered to provide the
		* new location.
		*/
		public boolean computeScrollOffset() {
		boolean inProgress = mCurrScroller.computeScrollOffset();

		switch (mScrollMode) {
		case MODE_OVERFLING:
		if (!inProgress) {
		// Overfling ended
		if (springback(mCurrScroller.getCurrX(), mCurrScroller.getCurrY(),
		mMinimumX, mMaximumX, mMinimumY, mMaximumY, mAccelDecelScroller)) {
		return mCurrScroller.computeScrollOffset();
		} else {
		mCurrScroller = mDefaultScroller;
		mScrollMode = MODE_DEFAULT;
		}
		}
		break;

		case MODE_SPRINGBACK:
		if (!inProgress) {
		mCurrScroller = mDefaultScroller;
		mScrollMode = MODE_DEFAULT;
		}
		break;

		case MODE_DEFAULT:
		// Fling/autoscroll - did we go off the edge?
		if (inProgress) {
		Scroller scroller = mCurrScroller;
		final int x = scroller.getCurrX();
		final int y = scroller.getCurrY();
		final int minX = mMinimumX;
		final int maxX = mMaximumX;
		final int minY = mMinimumY;
		final int maxY = mMaximumY;
		if (x < minX \|\| x > maxX \|\| y < minY \|\| y > maxY) {
		final int startx = scroller.getStartX();
		final int starty = scroller.getStartY();
		final int time = scroller.timePassed();
		final float timeSecs = time / 1000.f;
		final float xvel = ((x - startx) / timeSecs);
		final float yvel = ((y - starty) / timeSecs);

		if ((x < minX && xvel > 0) \|\| (y < minY && yvel > 0) \|\|
		(x > maxX && xvel < 0) \|\| (y > maxY && yvel < 0)) {
		// If our velocity would take us back into valid areas,
		// try to springback rather than overfling.
		if (springback(x, y, minX, maxX, minY, maxY)) {
		return mCurrScroller.computeScrollOffset();
		}
		} else {
		overfling(x, y, xvel, yvel);
		return mCurrScroller.computeScrollOffset();
		}
		}
		}
		break;
		}

		return inProgress;
		}

		private void overfling(int startx, int starty, float xvel, float yvel) {
		Scroller scroller = mDecelScroller;
		final float durationSecs = (OVERFLING_DURATION / 1000.f);
		int dx = (int)(xvel * durationSecs) / 8;
		int dy = (int)(yvel * durationSecs) / 8;
		scroller.startScroll(startx, starty, dx, dy, OVERFLING_DURATION);
		mCurrScroller.abortAnimation();
		mCurrScroller = scroller;
		mScrollMode = MODE_OVERFLING;
		}

		/**
		* Call this when you want to 'spring back' into a valid coordinate range.
		*
		* @param startX Starting X coordinate
		* @param startY Starting Y coordinate
		* @param minX Minimum valid X value
		* @param maxX Maximum valid X value
		* @param minY Minimum valid Y value
		* @param maxY Minimum valid Y value
		* @return true if a springback was initiated, false if startX/startY was
		* already within the valid range.
		*/
		public boolean springback(int startX, int startY, int minX, int maxX,
		int minY, int maxY) {
		return springback(startX, startY, minX, maxX, minY, maxY, mDecelScroller);
		}

		private boolean springback(int startX, int startY, int minX, int maxX,
		int minY, int maxY, Scroller scroller) {
		int xoff = 0;
		int yoff = 0;
		if (startX < minX) {
		xoff = minX - startX;
		} else if (startX > maxX) {
		xoff = maxX - startX;
		}
		if (startY < minY) {
		yoff = minY - startY;
		} else if (startY > maxY) {
		yoff = maxY - startY;
		}

		if (xoff != 0 \|\| yoff != 0) {
		scroller.startScroll(startX, startY, xoff, yoff, SPRINGBACK_DURATION);
		mCurrScroller.abortAnimation();
		mCurrScroller = scroller;
		mScrollMode = MODE_SPRINGBACK;
		return true;
		}

		return false;
		}

		/**
		*
		* Returns whether the scroller has finished scrolling.
		*
		* @return True if the scroller has finished scrolling, false otherwise.
		*/
		public final boolean isFinished() {
		return mCurrScroller.isFinished();
		}

		/**
		* Returns the current X offset in the scroll.
		*
		* @return The new X offset as an absolute distance from the origin.
		*/
		public final int getCurrX() {
		return mCurrScroller.getCurrX();
		}

		/**
		* Returns the current Y offset in the scroll.
		*
		* @return The new Y offset as an absolute distance from the origin.
		*/
		public final int getCurrY() {
		return mCurrScroller.getCurrY();
		}

		/**
		* Stops the animation, resets any springback/overfling and completes
		* any standard flings/scrolls in progress.
		*/
		public void abortAnimation() {
		mCurrScroller.abortAnimation();
		mCurrScroller = mDefaultScroller;
		mScrollMode = MODE_DEFAULT;
		mCurrScroller.abortAnimation();
		}

		/**
		* Start scrolling by providing a starting point and the distance to travel.
		* The scroll will use the default value of 250 milliseconds for the
		* duration.
		*
		* @param startX Starting horizontal scroll offset in pixels. Positive
		* numbers will scroll the content to the left.
		* @param startY Starting vertical scroll offset in pixels. Positive numbers
		* will scroll the content up.
		* @param dx Horizontal distance to travel. Positive numbers will scroll the
		* content to the left.
		* @param dy Vertical distance to travel. Positive numbers will scroll the
		* content up.
		*/
		public void startScroll(int startX, int startY, int dx, int dy) {
		mCurrScroller.abortAnimation();
		mCurrScroller = mDefaultScroller;
		mScrollMode = MODE_DEFAULT;
		mMinimumX = Math.min(startX, startX + dx);
		mMinimumY = Math.min(startY, startY + dy);
		mMaximumX = Math.max(startX, startX + dx);
		mMaximumY = Math.max(startY, startY + dy);
		mCurrScroller.startScroll(startX, startY, dx, dy);
		}

		/**
		* Start scrolling by providing a starting point and the distance to travel.
		*
		* @param startX Starting horizontal scroll offset in pixels. Positive
		* numbers will scroll the content to the left.
		* @param startY Starting vertical scroll offset in pixels. Positive numbers
		* will scroll the content up.
		* @param dx Horizontal distance to travel. Positive numbers will scroll the
		* content to the left.
		* @param dy Vertical distance to travel. Positive numbers will scroll the
		* content up.
		* @param duration Duration of the scroll in milliseconds.
		*/
		public void startScroll(int startX, int startY, int dx, int dy, int duration) {
		mCurrScroller.abortAnimation();
		mCurrScroller = mDefaultScroller;
		mScrollMode = MODE_DEFAULT;
		mMinimumX = Math.min(startX, startX + dx);
		mMinimumY = Math.min(startY, startY + dy);
		mMaximumX = Math.max(startX, startX + dx);
		mMaximumY = Math.max(startY, startY + dy);
		mCurrScroller.startScroll(startX, startY, dx, dy, duration);
		}

		/**
		* Returns the duration of the active scroll in progress; standard, fling,
		* springback, or overfling. Does not account for any overflings or springback
		* that may result.
		*/
		public int getDuration() {
		return mCurrScroller.getDuration();
		}

		/**
		* Start scrolling based on a fling gesture. The distance travelled will
		* depend on the initial velocity of the fling.
		*
		* @param startX Starting point of the scroll (X)
		* @param startY Starting point of the scroll (Y)
		* @param velocityX Initial velocity of the fling (X) measured in pixels per
		* second.
		* @param velocityY Initial velocity of the fling (Y) measured in pixels per
		* second
		* @param minX Minimum X value. The scroller will not scroll past this
		* point.
		* @param maxX Maximum X value. The scroller will not scroll past this
		* point.
		* @param minY Minimum Y value. The scroller will not scroll past this
		* point.
		* @param maxY Maximum Y value. The scroller will not scroll past this
		* point.
		*/
		public void fling(int startX, int startY, int velocityX, int velocityY,
		int minX, int maxX, int minY, int maxY) {
		this.fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY, 0, 0);
		}

		/**
		* Start scrolling based on a fling gesture. The distance travelled will
		* depend on the initial velocity of the fling.
		*
		* @param startX Starting point of the scroll (X)
		* @param startY Starting point of the scroll (Y)
		* @param velocityX Initial velocity of the fling (X) measured in pixels per
		* second.
		* @param velocityY Initial velocity of the fling (Y) measured in pixels per
		* second
		* @param minX Minimum X value. The scroller will not scroll past this
		* point unless overX > 0. If overfling is allowed, it will use minX
		* as a springback boundary.
		* @param maxX Maximum X value. The scroller will not scroll past this
		* point unless overX > 0. If overfling is allowed, it will use maxX
		* as a springback boundary.
		* @param minY Minimum Y value. The scroller will not scroll past this
		* point unless overY > 0. If overfling is allowed, it will use minY
		* as a springback boundary.
		* @param maxY Maximum Y value. The scroller will not scroll past this
		* point unless overY > 0. If overfling is allowed, it will use maxY
		* as a springback boundary.
		* @param overX Overfling range. If > 0, horizontal overfling in either
		* direction will be possible.
		* @param overY Overfling range. If > 0, vertical overfling in either
		* direction will be possible.
		*/
		public void fling(int startX, int startY, int velocityX, int velocityY,
		int minX, int maxX, int minY, int maxY, int overX, int overY) {
		mCurrScroller = mDefaultScroller;
		mScrollMode = MODE_DEFAULT;
		mMinimumX = minX;
		mMaximumX = maxX;
		mMinimumY = minY;
		mMaximumY = maxY;
		mCurrScroller.fling(startX, startY, velocityX, velocityY,
		minX - overX, maxX + overX, minY - overY, maxY + overY);
		}

		/**
		* Returns where the scroll will end. Valid only for "fling" scrolls.
		*
		* @return The final X offset as an absolute distance from the origin.
		*/
		public int getFinalX() {
		return mCurrScroller.getFinalX();
		}

		/**
		* Returns where the scroll will end. Valid only for "fling" scrolls.
		*
		* @return The final Y offset as an absolute distance from the origin.
		*/
		public int getFinalY() {
		return mCurrScroller.getFinalY();
		}
		}

core/java/android/widget/ScrollView.java

+21 −35

Original line number	Diff line number	Diff line
		@@ -16,6 +16,8 @@

		package android.widget;

		import com.android.internal.R;

		import android.content.Context;
		import android.content.res.TypedArray;
		import android.graphics.Rect;
		@@ -30,8 +32,6 @@ import android.view.ViewGroup;
		import android.view.ViewParent;
		import android.view.animation.AnimationUtils;

		import com.android.internal.R;

		import java.util.List;

		/**
		@@ -59,7 +59,7 @@ public class ScrollView extends FrameLayout {
		private long mLastScroll;

		private final Rect mTempRect = new Rect();
		private Scroller mScroller;
		private OverScroller mScroller;

		/**
		* Flag to indicate that we are moving focus ourselves. This is so the
		@@ -173,7 +173,7 @@ public class ScrollView extends FrameLayout {


		private void initScrollView() {
		mScroller = new Scroller(getContext());
		mScroller = new OverScroller(getContext());
		setFocusable(true);
		setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
		setWillNotDraw(false);
		@@ -378,11 +378,6 @@ public class ScrollView extends FrameLayout {
		return true;
		}

		if (!canScroll()) {
		mIsBeingDragged = false;
		return false;
		}

		final float y = ev.getY();

		switch (action) {
		@@ -438,10 +433,6 @@ public class ScrollView extends FrameLayout {
		return false;
		}

		if (!canScroll()) {
		return false;
		}

		if (mVelocityTracker == null) {
		mVelocityTracker = VelocityTracker.obtain();
		}
		@@ -468,25 +459,23 @@ public class ScrollView extends FrameLayout {
		final int deltaY = (int) (mLastMotionY - y);
		mLastMotionY = y;

		if (deltaY < 0) {
		if (mScrollY > 0) {
		scrollBy(0, deltaY);
		}
		} else if (deltaY > 0) {
		final int bottomEdge = getHeight() - mPaddingBottom;
		final int availableToScroll = getChildAt(0).getBottom() - mScrollY - bottomEdge;
		if (availableToScroll > 0) {
		scrollBy(0, Math.min(availableToScroll, deltaY));
		}
		}
		super.scrollTo(mScrollX, mScrollY + deltaY);
		break;
		case MotionEvent.ACTION_UP:
		final VelocityTracker velocityTracker = mVelocityTracker;
		velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
		int initialVelocity = (int) velocityTracker.getYVelocity();

		if ((Math.abs(initialVelocity) > mMinimumVelocity) && getChildCount() > 0) {
		if (getChildCount() > 0) {
		if ((Math.abs(initialVelocity) > mMinimumVelocity)) {
		fling(-initialVelocity);
		} else {
		final int bottom = Math.max(0, getChildAt(0).getHeight() -
		(getHeight() - mPaddingBottom - mPaddingTop));
		if (mScroller.springback(mScrollX, mScrollY, 0, 0, 0, bottom)) {
		invalidate();
		}
		}
		}

		if (mVelocityTracker != null) {
		@@ -915,14 +904,10 @@ public class ScrollView extends FrameLayout {
		int oldY = mScrollY;
		int x = mScroller.getCurrX();
		int y = mScroller.getCurrY();
		if (getChildCount() > 0) {
		View child = getChildAt(0);
		mScrollX = clamp(x, getWidth() - mPaddingRight - mPaddingLeft, child.getWidth());
		mScrollY = clamp(y, getHeight() - mPaddingBottom - mPaddingTop, child.getHeight());
		} else {

		mScrollX = x;
		mScrollY = y;
		}

		if (oldX != mScrollX \|\| oldY != mScrollY) {
		onScrollChanged(mScrollX, mScrollY, oldX, oldY);
		}
		@@ -1159,7 +1144,8 @@ public class ScrollView extends FrameLayout {
		int height = getHeight() - mPaddingBottom - mPaddingTop;
		int bottom = getChildAt(0).getHeight();

		mScroller.fling(mScrollX, mScrollY, 0, velocityY, 0, 0, 0, bottom - height);
		mScroller.fling(mScrollX, mScrollY, 0, velocityY, 0, 0, 0,
		Math.max(0, bottom - height), 0, height/2);

		final boolean movingDown = velocityY > 0;