Add AbsListView#smoothScrollToPositionFromTop (e44afae7) · Commits · e / os / android_frameworks_base

api/current.xml

+15 −0

Original line number	Original line	Diff line number	Diff line
	@@ -205332,6 +205332,21 @@
	<parameter name="boundPosition" type="int">		<parameter name="boundPosition" type="int">
	</parameter>		</parameter>
	</method>		</method>
			<method name="smoothScrollToPositionFromTop"
			return="void"
			abstract="false"
			native="false"
			synchronized="false"
			static="false"
			final="false"
			deprecated="not deprecated"
			visibility="public"
			>
			<parameter name="position" type="int">
			</parameter>
			<parameter name="offset" type="int">
			</parameter>
			</method>
	<method name="verifyDrawable"		<method name="verifyDrawable"
	return="boolean"		return="boolean"
	abstract="false"		abstract="false"

core/java/android/widget/AbsListView.java

+76 −2

Original line number	Original line	Diff line number	Diff line
	@@ -2541,6 +2541,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
	private static final int MOVE_UP_POS = 2;		private static final int MOVE_UP_POS = 2;
	private static final int MOVE_DOWN_BOUND = 3;		private static final int MOVE_DOWN_BOUND = 3;
	private static final int MOVE_UP_BOUND = 4;		private static final int MOVE_UP_BOUND = 4;
			private static final int MOVE_OFFSET = 5;

	private int mMode;		private int mMode;
	private int mTargetPos;		private int mTargetPos;
	@@ -2549,6 +2550,8 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
	private int mScrollDuration;		private int mScrollDuration;
	private final int mExtraScroll;		private final int mExtraScroll;

			private int mOffsetFromTop;

	PositionScroller() {		PositionScroller() {
	mExtraScroll = ViewConfiguration.get(mContext).getScaledFadingEdgeLength();		mExtraScroll = ViewConfiguration.get(mContext).getScaledFadingEdgeLength();
	}		}
	@@ -2640,6 +2643,32 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
	post(this);		post(this);
	}		}

			void startWithOffset(int position, int offset) {
			mTargetPos = position;
			mOffsetFromTop = offset;
			mBoundPos = INVALID_POSITION;
			mLastSeenPos = INVALID_POSITION;
			mMode = MOVE_OFFSET;

			final int firstPos = mFirstPosition;
			final int lastPos = firstPos + getChildCount() - 1;

			int viewTravelCount = 0;
			if (position < firstPos) {
			viewTravelCount = firstPos - position;
			} else if (position > lastPos) {
			viewTravelCount = position - lastPos;
			} else {
			// On-screen, just scroll.
			final int targetTop = getChildAt(position - firstPos).getTop();
			smoothScrollBy(targetTop - offset, SCROLL_DURATION);
			return;
			}

			mScrollDuration = SCROLL_DURATION / viewTravelCount;
			post(this);
			}

	void stop() {		void stop() {
	removeCallbacks(this);		removeCallbacks(this);
	}		}
	@@ -2769,6 +2798,33 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
	break;		break;
	}		}

			case MOVE_OFFSET: {
			if (firstPos == mLastSeenPos) {
			// No new views, let things keep going.
			post(this);
			}

			final int position = mTargetPos;
			final int lastPos = firstPos + getChildCount() - 1;

			if (position < firstPos) {
			final View firstView = getChildAt(0);
			final int firstViewPixelsShowing = firstView.getHeight() + firstView.getTop();
			smoothScrollBy(-firstViewPixelsShowing, mScrollDuration);
			post(this);
			} else if (position > lastPos) {
			final View lastView = getChildAt(getChildCount() - 1);
			final int lastViewPixelsShowing = lastView.getBottom() - lastView.getHeight();
			smoothScrollBy(lastViewPixelsShowing, mScrollDuration);
			post(this);
			} else {
			// On-screen, just scroll.
			final int targetTop = getChildAt(position - firstPos).getTop();
			smoothScrollBy(targetTop - mOffsetFromTop, mScrollDuration);
			}
			break;
			}

	default:		default:
	break;		break;
	}		}
	@@ -2787,6 +2843,24 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
	mPositionScroller.start(position);		mPositionScroller.start(position);
	}		}

			/**
			* Smoothly scroll to the specified adapter position. The view will scroll
			* such that the indicated position is displayed <code>offset</code> pixels from
			* the top edge of the view. If this is impossible, (e.g. the offset would scroll
			* the first or last item beyond the boundaries of the list) it will get as close
			* as possible.
			*
			* @param position Position to scroll to
			* @param offset Desired distance in pixels of <code>position</code> from the top
			* of the view when scrolling is finished
			*/
			public void smoothScrollToPositionFromTop(int position, int offset) {
			if (mPositionScroller == null) {
			mPositionScroller = new PositionScroller();
			}
			mPositionScroller.startWithOffset(position, offset);
			}

	/**		/**
	* Smoothly scroll to the specified adapter position. The view will		* Smoothly scroll to the specified adapter position. The view will
	* scroll such that the indicated position is displayed, but it will		* scroll such that the indicated position is displayed, but it will