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Commit 9b56a605 authored by George Mount's avatar George Mount
Browse files

Calculate velocity when using smooth scrolling 

Fixes: 329933898

When using scrolling, Overscroller now calculates
the current velocity so that it can be used with
ScrollView, HorizontalScrollView, and AbsListView.

Test: new tests for ScrollView and HorizontalScrollView
Change-Id: I0870b12f2afa751d12a4afa8ce473451c4e93ed4
parent 1cc982e9

core/java/android/widget/OverScroller.java

+9 −4
Original line number Diff line number Diff line
@@ -299,8 +299,10 @@ public class OverScroller { 
                final int duration = mScrollerX.mDuration;

                if (elapsedTime < duration) {

                    final float q = mInterpolator.getInterpolation(elapsedTime / (float) duration);

                    mScrollerX.updateScroll(q);

                    mScrollerY.updateScroll(q);

                    final float q2 =

                            mInterpolator.getInterpolation((elapsedTime - 1) / (float) duration);

                    mScrollerX.updateScroll(q, q2);

                    mScrollerY.updateScroll(q, q2);

                } else {

                    abortAnimation();

                }
@@ -642,8 +644,11 @@ public class OverScroller { 
                    * 0.84f; // look and feel tuning

        }



        void updateScroll(float q) {

            mCurrentPosition = mStart + Math.round(q * (mFinal - mStart));

        void updateScroll(float q, float q2) {

            int distance = mFinal - mStart;

            mCurrentPosition = mStart + Math.round(q * distance);

            // q2 is 1ms before q1

            mCurrVelocity = 1000f * (q - q2) * distance;

        }



        /*

core/tests/coretests/res/layout/activity_horizontal_scroll_view.xml

+15 −15
Original line number Diff line number Diff line
@@ -22,7 +22,7 @@ 


    <HorizontalScrollView

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:layout_height="wrap_content"

        android:id="@+id/horizontal_scroll_view">



        <LinearLayout
@@ -133,31 +133,31 @@ 
        <LinearLayout

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:orientation="vertical">

            android:orientation="horizontal">

            <View

                android:background="#00F"

                android:layout_width="90dp"

                android:layout_height="50dp"/>

                android:layout_width="100dp"

                android:layout_height="90dp"/>

            <View

                android:background="#0FF"

                android:layout_width="90dp"

                android:layout_height="50dp"/>

                android:layout_width="100dp"

                android:layout_height="90dp"/>

            <View

                android:background="#0F0"

                android:layout_width="90dp"

                android:layout_height="50dp"/>

                android:layout_width="100dp"

                android:layout_height="90dp"/>

            <View

                android:background="#FF0"

                android:layout_width="90dp"

                android:layout_height="50dp"/>

                android:layout_width="100dp"

                android:layout_height="90dp"/>

            <View

                android:background="#F00"

                android:layout_width="90dp"

                android:layout_height="50dp"/>

                android:layout_width="100dp"

                android:layout_height="90dp"/>

            <View

                android:background="#F0F"

                android:layout_width="90dp"

                android:layout_height="50dp"/>

                android:layout_width="100dp"

                android:layout_height="90dp"/>

        </LinearLayout>

    </view>

</LinearLayout>

core/tests/coretests/res/layout/activity_scroll_view.xml

+2 −2
Original line number Diff line number Diff line
@@ -18,10 +18,10 @@ 
    xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical">

    android:orientation="horizontal">



    <ScrollView

        android:layout_width="match_parent"

        android:layout_width="wrap_content"

        android:layout_height="match_parent"

        android:id="@+id/scroll_view">

core/tests/coretests/src/android/widget/HorizontalScrollViewFunctionalTest.java

+22 −6
Original line number Diff line number Diff line
@@ -99,13 +99,29 @@ public class HorizontalScrollViewFunctionalTest { 
            mMyHorizontalScrollView.setFrameContentVelocity(0);

        });

        // set setFrameContentVelocity shouldn't do anything.

        assertEquals(mMyHorizontalScrollView.isSetVelocityCalled, false);

        assertTrue(mMyHorizontalScrollView.isSetVelocityCalled);

        assertEquals(0f, mMyHorizontalScrollView.velocity, 0f);

        mMyHorizontalScrollView.isSetVelocityCalled = false;



        mActivityRule.runOnUiThread(() -> {

            mMyHorizontalScrollView.fling(100);

        });

        // set setFrameContentVelocity should be called when fling.

        assertEquals(mMyHorizontalScrollView.isSetVelocityCalled, true);

        assertTrue(mMyHorizontalScrollView.isSetVelocityCalled);

        assertTrue(mMyHorizontalScrollView.velocity > 0f);

    }



    @Test

    @RequiresFlagsEnabled(FLAG_VIEW_VELOCITY_API)

    public void hasVelocityInSmoothScrollBy() throws Throwable {

        int maxScroll = mMyHorizontalScrollView.getChildAt(0).getWidth()

                - mMyHorizontalScrollView.getWidth();

        mActivityRule.runOnUiThread(() -> {

            mMyHorizontalScrollView.smoothScrollTo(maxScroll, 0);

        });

        PollingCheck.waitFor(() -> mMyHorizontalScrollView.getScrollX() != 0);

        assertTrue(mMyHorizontalScrollView.isSetVelocityCalled);

        assertTrue(mMyHorizontalScrollView.velocity > 0f);

    }



    static class WatchedEdgeEffect extends EdgeEffect {
@@ -122,9 +138,10 @@ public class HorizontalScrollViewFunctionalTest { 
        }

    }



    public static class MyHorizontalScrollView extends ScrollView {

    public static class MyHorizontalScrollView extends HorizontalScrollView {



        public boolean isSetVelocityCalled;

        public float velocity;



        public MyHorizontalScrollView(Context context) {

            super(context);
@@ -140,9 +157,8 @@ public class HorizontalScrollViewFunctionalTest { 


        @Override

        public void setFrameContentVelocity(float pixelsPerSecond) {

            if (pixelsPerSecond != 0) {

            isSetVelocityCalled = true;

            }

            velocity = pixelsPerSecond;

        }

    }

}

core/tests/coretests/src/android/widget/ScrollViewFunctionalTest.java

+22 −5
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ package android.widget; 
import static android.view.flags.Flags.FLAG_VIEW_VELOCITY_API;



import static org.junit.Assert.assertEquals;

import static org.junit.Assert.assertNotEquals;

import static org.junit.Assert.assertTrue;



import android.content.Context;
@@ -98,13 +99,28 @@ public class ScrollViewFunctionalTest { 
            mMyScrollView.setFrameContentVelocity(0);

        });

        // set setFrameContentVelocity shouldn't do anything.

        assertEquals(mMyScrollView.isSetVelocityCalled, false);

        assertTrue(mMyScrollView.isSetVelocityCalled);

        assertEquals(0f, mMyScrollView.velocity, 0f);

        mMyScrollView.isSetVelocityCalled = false;



        mActivityRule.runOnUiThread(() -> {

            mMyScrollView.fling(100);

        });

        // set setFrameContentVelocity should be called when fling.

        assertEquals(mMyScrollView.isSetVelocityCalled, true);

        assertTrue(mMyScrollView.isSetVelocityCalled);

        assertNotEquals(0f, mMyScrollView.velocity, 0.01f);

    }



    @Test

    @RequiresFlagsEnabled(FLAG_VIEW_VELOCITY_API)

    public void hasVelocityInSmoothScrollBy() throws Throwable {

        int maxScroll = mMyScrollView.getChildAt(0).getHeight() - mMyScrollView.getHeight();

        mActivityRule.runOnUiThread(() -> {

            mMyScrollView.smoothScrollTo(0, maxScroll);

        });

        PollingCheck.waitFor(() -> mMyScrollView.getScrollY() != 0);

        assertTrue(mMyScrollView.isSetVelocityCalled);

        assertTrue(mMyScrollView.velocity > 0f);

    }



    static class WatchedEdgeEffect extends EdgeEffect {
@@ -125,6 +141,8 @@ public class ScrollViewFunctionalTest { 


        public boolean isSetVelocityCalled;



        public float velocity;



        public MyScrollView(Context context) {

            super(context);

        }
@@ -139,9 +157,8 @@ public class ScrollViewFunctionalTest { 


        @Override

        public void setFrameContentVelocity(float pixelsPerSecond) {

            if (pixelsPerSecond != 0) {

            isSetVelocityCalled = true;

            }

            velocity = pixelsPerSecond;

        }

    }

}