Improve reordering by always using the "push mechanic" if possible (issue 6275309)
Change-Id: I51450c1b1f6b439c87194a6084d82fb9989154a7
diff --git a/src/com/android/launcher2/CellLayout.java b/src/com/android/launcher2/CellLayout.java
index a96b5b1..c028ff1 100644
--- a/src/com/android/launcher2/CellLayout.java
+++ b/src/com/android/launcher2/CellLayout.java
@@ -1704,6 +1704,102 @@
markCellsForView(r.left, r.top, r.width(), r.height(), occupied, value);
}
+ // This method tries to find a reordering solution which satisfies the push mechanic by trying
+ // to push items in each of the cardinal directions, in an order based on the direction vector
+ // passed.
+ private boolean attemptPushInDirection(ArrayList<View> intersectingViews, Rect occupied,
+ int[] direction, View ignoreView, ItemConfiguration solution) {
+ if ((Math.abs(direction[0]) + Math.abs(direction[1])) > 1) {
+ // If the direction vector has two non-zero components, we try pushing
+ // separately in each of the components.
+ int temp = direction[1];
+ direction[1] = 0;
+ if (addViewsToTempLocation(intersectingViews, occupied, direction, true,
+ ignoreView, solution)) {
+ return true;
+ }
+ direction[1] = temp;
+ temp = direction[0];
+ direction[0] = 0;
+ if (addViewsToTempLocation(intersectingViews, occupied, direction, true,
+ ignoreView, solution)) {
+ return true;
+ }
+ // Revert the direction
+ direction[0] = temp;
+
+ // Now we try pushing in each component of the opposite direction
+ direction[0] *= -1;
+ direction[1] *= -1;
+ temp = direction[1];
+ direction[1] = 0;
+ if (addViewsToTempLocation(intersectingViews, occupied, direction, true,
+ ignoreView, solution)) {
+ return true;
+ }
+
+ direction[1] = temp;
+ temp = direction[0];
+ direction[0] = 0;
+ if (addViewsToTempLocation(intersectingViews, occupied, direction, true,
+ ignoreView, solution)) {
+ return true;
+ }
+ // revert the direction
+ direction[0] = temp;
+ direction[0] *= -1;
+ direction[1] *= -1;
+
+ } else {
+ // If the direction vector has a single non-zero component, we push first in the
+ // direction of the vector
+ if (addViewsToTempLocation(intersectingViews, occupied, direction, true,
+ ignoreView, solution)) {
+ return true;
+ }
+
+ // Then we try the opposite direction
+ direction[0] *= -1;
+ direction[1] *= -1;
+ if (addViewsToTempLocation(intersectingViews, occupied, direction, true,
+ ignoreView, solution)) {
+ return true;
+ }
+ // Switch the direction back
+ direction[0] *= -1;
+ direction[1] *= -1;
+
+ // If we have failed to find a push solution with the above, then we try
+ // to find a solution by pushing along the perpendicular axis.
+
+ // Swap the components
+ int temp = direction[1];
+ direction[1] = direction[0];
+ direction[0] = temp;
+ if (addViewsToTempLocation(intersectingViews, occupied, direction, true,
+ ignoreView, solution)) {
+ return true;
+ }
+
+ // Then we try the opposite direction
+ direction[0] *= -1;
+ direction[1] *= -1;
+ if (addViewsToTempLocation(intersectingViews, occupied, direction, true,
+ ignoreView, solution)) {
+ return true;
+ }
+ // Switch the direction back
+ direction[0] *= -1;
+ direction[1] *= -1;
+
+ // Swap the components back
+ temp = direction[1];
+ direction[1] = direction[0];
+ direction[0] = temp;
+ }
+ return false;
+ }
+
private boolean rearrangementExists(int cellX, int cellY, int spanX, int spanY, int[] direction,
View ignoreView, ItemConfiguration solution) {
// Return early if get invalid cell positions
@@ -1735,23 +1831,15 @@
}
}
- // We try to move the intersecting views as a block using the push mechanic
- if (addViewsToTempLocation(mIntersectingViews, mOccupiedRect, direction, true, ignoreView,
+ // First we try to find a solution which respects the push mechanic. That is,
+ // we try to find a solution such that no displaced item travels through another item
+ // without also displacing that item.
+ if (attemptPushInDirection(mIntersectingViews, mOccupiedRect, direction, ignoreView,
solution)) {
return true;
}
- // Try the opposite direction
- direction[0] *= -1;
- direction[1] *= -1;
- if (addViewsToTempLocation(mIntersectingViews, mOccupiedRect, direction, true, ignoreView,
- solution)) {
- return true;
- }
- // Switch the direction back
- direction[0] *= -1;
- direction[1] *= -1;
- // Next we try moving the views as a block , but without requiring the push mechanic
+ // Next we try moving the views as a block, but without requiring the push mechanic.
if (addViewsToTempLocation(mIntersectingViews, mOccupiedRect, direction, false, ignoreView,
solution)) {
return true;