Add an API to control AbsListView's friction. (4bede9e4) · Commits · e / os / android_frameworks_base

api/current.xml

+26 −0

Original line number	Diff line number	Diff line
		@@ -225144,6 +225144,19 @@
		<parameter name="filterText" type="java.lang.String">
		</parameter>
		</method>
		<method name="setFriction"
		return="void"
		abstract="false"
		native="false"
		synchronized="false"
		static="false"
		final="false"
		deprecated="not deprecated"
		visibility="public"
		>
		<parameter name="friction" type="float">
		</parameter>
		</method>
		<method name="setItemChecked"
		return="void"
		abstract="false"
		@@ -238705,6 +238718,19 @@
		<parameter name="newY" type="int">
		</parameter>
		</method>
		<method name="setFriction"
		return="void"
		abstract="false"
		native="false"
		synchronized="false"
		static="false"
		final="true"
		deprecated="not deprecated"
		visibility="public"
		>
		<parameter name="friction" type="float">
		</parameter>
		</method>
		<method name="startScroll"
		return="void"
		abstract="false"

core/java/android/widget/AbsListView.java

+17 −19

Original line number	Diff line number	Diff line
		@@ -2965,7 +2965,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
		final int firstPos = mFirstPosition;
		final int lastPos = firstPos + getChildCount() - 1;

		int viewTravelCount = 0;
		int viewTravelCount;
		if (position <= firstPos) {
		viewTravelCount = firstPos - position + 1;
		mMode = MOVE_UP_POS;
		@@ -2998,7 +2998,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
		final int firstPos = mFirstPosition;
		final int lastPos = firstPos + getChildCount() - 1;

		int viewTravelCount = 0;
		int viewTravelCount;
		if (position <= firstPos) {
		final int boundPosFromLast = lastPos - boundPosition;
		if (boundPosFromLast < 1) {
		@@ -3059,7 +3059,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
		final int childCount = getChildCount();
		final int lastPos = firstPos + childCount - 1;

		int viewTravelCount = 0;
		int viewTravelCount;
		if (position < firstPos) {
		viewTravelCount = firstPos - position;
		} else if (position > lastPos) {
		@@ -3248,6 +3248,20 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
		}
		}

		/**
		* The amount of friction applied to flings. The default value
		* is {@link ViewConfiguration#getScrollFriction}.
		*
		* @return A scalar dimensionless value representing the coefficient of
		* friction.
		*/
		public void setFriction(float friction) {
		if (mFlingRunnable == null) {
		mFlingRunnable = new FlingRunnable();
		}
		mFlingRunnable.mScroller.setFriction(friction);
		}

		/**
		* Smoothly scroll to the specified adapter position. The view will
		* scroll such that the indicated position is displayed.
		@@ -3582,22 +3596,6 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
		*/
		abstract int findMotionRow(int y);

		/**
		* Find the row closest to y. This row will be used as the motion row when scrolling.
		*
		* @param y Where the user touched
		* @return The position of the first (or only) item in the row closest to y
		*/
		int findClosestMotionRow(int y) {
		final int childCount = getChildCount();
		if (childCount == 0) {
		return INVALID_POSITION;
		}

		final int motionRow = findMotionRow(y);
		return motionRow != INVALID_POSITION ? motionRow : mFirstPosition + childCount - 1;
		}

		/**
		* Causes all the views to be rebuilt and redrawn.
		*/

core/java/android/widget/Scroller.java

+22 −6

Original line number	Diff line number	Diff line
		@@ -63,7 +63,8 @@ public class Scroller {
		private static final int SCROLL_MODE = 0;
		private static final int FLING_MODE = 1;

		private final float mDeceleration;
		private float mDeceleration;
		private final float mPpi;

		/**
		* Create a Scroller with the default duration and interpolator.
		@@ -79,11 +80,26 @@ public class Scroller {
		public Scroller(Context context, Interpolator interpolator) {
		mFinished = true;
		mInterpolator = interpolator;
		float ppi = context.getResources().getDisplayMetrics().density * 160.0f;
		mDeceleration = SensorManager.GRAVITY_EARTH // g (m/s^2)
		mPpi = context.getResources().getDisplayMetrics().density * 160.0f;
		mDeceleration = computeDeceleration(ViewConfiguration.getScrollFriction());
		}

		/**
		* The amount of friction applied to flings. The default value
		* is {@link ViewConfiguration#getScrollFriction}.
		*
		* @return A scalar dimensionless value representing the coefficient of
		* friction.
		*/
		public final void setFriction(float friction) {
		computeDeceleration(friction);
		}

		private float computeDeceleration(float friction) {
		return SensorManager.GRAVITY_EARTH // g (m/s^2)
		* 39.37f // inch/meter
		* ppi // pixels per inch
		* ViewConfiguration.getScrollFriction();
		* mPpi // pixels per inch
		* friction;
		}

		/**