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author | Katie McCormick <kmccormick@google.com> | 2013-02-06 18:15:13 -0800 |
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committer | Katie McCormick <kmccormick@google.com> | 2013-02-07 16:42:26 -0800 |
commit | 87cfad7d742c8fae1ac268168e2ada286d330ef1 (patch) | |
tree | 258c0209b9f70c8b7a4c552f77b1d040dfb64ebc /core | |
parent | 00f490844d89b146e5490204a5a483834950c489 (diff) | |
download | frameworks_base-87cfad7d742c8fae1ac268168e2ada286d330ef1.zip frameworks_base-87cfad7d742c8fae1ac268168e2ada286d330ef1.tar.gz frameworks_base-87cfad7d742c8fae1ac268168e2ada286d330ef1.tar.bz2 |
Doc change: Scroller Javadoc Bug # 7966653
Change-Id: I4365946f890a76fcfa78ca9d69f2a8e0848095a9
Diffstat (limited to 'core')
-rw-r--r-- | core/java/android/widget/Scroller.java | 44 |
1 files changed, 36 insertions, 8 deletions
diff --git a/core/java/android/widget/Scroller.java b/core/java/android/widget/Scroller.java index 3a28e75..3bfd39d 100644 --- a/core/java/android/widget/Scroller.java +++ b/core/java/android/widget/Scroller.java @@ -26,11 +26,39 @@ import android.view.animation.Interpolator; /** - * This class encapsulates scrolling. The duration of the scroll - * can be passed in the constructor and specifies the maximum time that - * the scrolling animation should take. Past this time, the scrolling is - * automatically moved to its final stage and computeScrollOffset() - * will always return false to indicate that scrolling is over. + * <p>This class encapsulates scrolling. You can use scrollers ({@link Scroller} + * or {@link OverScroller}) to collect the data you need to produce a scrolling + * animation—for example, in response to a fling gesture. Scrollers track + * scroll offsets for you over time, but they don't automatically apply those + * positions to your view. It's your responsibility to get and apply new + * coordinates at a rate that will make the scrolling animation look smooth.</p> + * + * <p>Here is a simple example:</p> + * + * <pre> private Scroller mScroller = new Scroller(context); + * ... + * public void zoomIn() { + * // Revert any animation currently in progress + * mScroller.forceFinished(true); + * // Start scrolling by providing a starting point and + * // the distance to travel + * mScroller.startScroll(0, 0, 100, 0); + * // Invalidate to request a redraw + * invalidate(); + * }</pre> + * + * <p>To track the changing positions of the x/y coordinates, use + * {@link #computeScrollOffset}. The method returns a boolean to indicate + * whether the scroller is finished. If it isn't, it means that a fling or + * programmatic pan operation is still in progress. You can use this method to + * find the current offsets of the x and y coordinates, for example:</p> + * + * <pre>if (mScroller.computeScrollOffset()) { + * // Get current x and y positions + * int currX = mScroller.getCurrX(); + * int currY = mScroller.getCurrY(); + * ... + * }</pre> */ public class Scroller { private int mMode; @@ -272,8 +300,7 @@ public class Scroller { /** * 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. + * the animation is not yet finished. */ public boolean computeScrollOffset() { if (mFinished) { @@ -355,7 +382,8 @@ public class Scroller { } /** - * Start scrolling by providing a starting point and the distance to travel. + * Start scrolling by providing a starting point, the distance to travel, + * and the duration of the scroll. * * @param startX Starting horizontal scroll offset in pixels. Positive * numbers will scroll the content to the left. |