Fixing PagedView bad snap-back decisions
-> There was some code that was causing pages to snap back
much to the original page much too frequently.
Change-Id: Ibd02ac634c737887a2bcfd7096882c95c51087f1
diff --git a/src/com/android/launcher2/PagedView.java b/src/com/android/launcher2/PagedView.java
index 935d26d..f080721 100644
--- a/src/com/android/launcher2/PagedView.java
+++ b/src/com/android/launcher2/PagedView.java
@@ -61,8 +61,6 @@
// the min drag distance for a fling to register, to prevent random page shifts
private static final int MIN_LENGTH_FOR_FLING = 25;
- // The min drag distance to trigger a page shift (regardless of velocity)
- private static final int MIN_LENGTH_FOR_MOVE = 200;
private static final int PAGE_SNAP_ANIMATION_DURATION = 550;
protected static final float NANOTIME_DIV = 1000000000.0f;
@@ -72,6 +70,8 @@
private static final int MINIMUM_SNAP_VELOCITY = 2200;
private static final int MIN_FLING_VELOCITY = 250;
private static final float RETURN_TO_ORIGINAL_PAGE_THRESHOLD = 0.33f;
+ // The page is moved more than halfway, automatically move to the next page on touch up.
+ private static final float SIGNIFICANT_MOVE_THRESHOLD = 0.4f;
// the velocity at which a fling gesture will cause us to snap to the next page
protected int mSnapVelocity = 500;
@@ -1205,24 +1205,25 @@
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int velocityX = (int) velocityTracker.getXVelocity(activePointerId);
final int deltaX = (int) (x - mDownMotionX);
- boolean isSignificantMove = Math.abs(deltaX) > MIN_LENGTH_FOR_MOVE;
+ final int pageWidth = getScaledMeasuredWidth(getPageAt(mCurrentPage));
+ boolean isSignificantMove = Math.abs(deltaX) > pageWidth *
+ SIGNIFICANT_MOVE_THRESHOLD;
final int snapVelocity = mSnapVelocity;
mTotalMotionX += Math.abs(mLastMotionX + mLastMotionXRemainder - x);
+ boolean isFling = mTotalMotionX > MIN_LENGTH_FOR_FLING &&
+ Math.abs(velocityX) > snapVelocity;
+
// In the case that the page is moved far to one direction and then is flung
// in the opposite direction, we use a threshold to determine whether we should
// just return to the starting page, or if we should skip one further.
boolean returnToOriginalPage = false;
- final int pageWidth = getScaledMeasuredWidth(getPageAt(mCurrentPage));
if (Math.abs(deltaX) > pageWidth * RETURN_TO_ORIGINAL_PAGE_THRESHOLD &&
- Math.signum(velocityX) != Math.signum(deltaX)) {
+ Math.signum(velocityX) != Math.signum(deltaX) && isFling) {
returnToOriginalPage = true;
}
- boolean isFling = mTotalMotionX > MIN_LENGTH_FOR_FLING &&
- Math.abs(velocityX) > snapVelocity;
-
int finalPage;
// We give flings precedence over large moves, which is why we short-circuit our
// test for a large move if a fling has been registered. That is, a large