OpReordererpublic class OpReorderer extends Object
| Fields Summary |
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| final Callback | mCallback |
| Constructors Summary |
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public OpReorderer(Callback callback)
mCallback = callback;
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| Methods Summary |
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| private int | getLastMoveOutOfOrder(java.util.List list)
boolean foundNonMove = false;
for (int i = list.size() - 1; i >= 0; i--) {
final UpdateOp op1 = list.get(i);
if (op1.cmd == MOVE) {
if (foundNonMove) {
return i;
}
} else {
foundNonMove = true;
}
}
return -1;
| | void | reorderOps(java.util.List ops)
// since move operations breaks continuity, their effects on ADD/RM are hard to handle.
// we push them to the end of the list so that they can be handled easily.
int badMove;
while ((badMove = getLastMoveOutOfOrder(ops)) != -1) {
swapMoveOp(ops, badMove, badMove + 1);
}
| | private void | swapMoveAdd(java.util.List list, int move, android.support.v7.widget.AdapterHelper.UpdateOp moveOp, int add, android.support.v7.widget.AdapterHelper.UpdateOp addOp)
int offset = 0;
// going in reverse, first revert the effect of add
if (moveOp.itemCount < addOp.positionStart) {
offset--;
}
if (moveOp.positionStart < addOp.positionStart) {
offset++;
}
if (addOp.positionStart <= moveOp.positionStart) {
moveOp.positionStart += addOp.itemCount;
}
if (addOp.positionStart <= moveOp.itemCount) {
moveOp.itemCount += addOp.itemCount;
}
addOp.positionStart += offset;
list.set(move, addOp);
list.set(add, moveOp);
| | private void | swapMoveOp(java.util.List list, int badMove, int next)
final UpdateOp moveOp = list.get(badMove);
final UpdateOp nextOp = list.get(next);
switch (nextOp.cmd) {
case REMOVE:
swapMoveRemove(list, badMove, moveOp, next, nextOp);
break;
case ADD:
swapMoveAdd(list, badMove, moveOp, next, nextOp);
break;
case UPDATE:
swapMoveUpdate(list, badMove, moveOp, next, nextOp);
break;
}
| | void | swapMoveRemove(java.util.List list, int movePos, android.support.v7.widget.AdapterHelper.UpdateOp moveOp, int removePos, android.support.v7.widget.AdapterHelper.UpdateOp removeOp)
UpdateOp extraRm = null;
// check if move is nulled out by remove
boolean revertedMove = false;
final boolean moveIsBackwards;
if (moveOp.positionStart < moveOp.itemCount) {
moveIsBackwards = false;
if (removeOp.positionStart == moveOp.positionStart
&& removeOp.itemCount == moveOp.itemCount - moveOp.positionStart) {
revertedMove = true;
}
} else {
moveIsBackwards = true;
if (removeOp.positionStart == moveOp.itemCount + 1 &&
removeOp.itemCount == moveOp.positionStart - moveOp.itemCount) {
revertedMove = true;
}
}
// going in reverse, first revert the effect of add
if (moveOp.itemCount < removeOp.positionStart) {
removeOp.positionStart--;
} else if (moveOp.itemCount < removeOp.positionStart + removeOp.itemCount) {
// move is removed.
removeOp.itemCount --;
moveOp.cmd = REMOVE;
moveOp.itemCount = 1;
if (removeOp.itemCount == 0) {
list.remove(removePos);
mCallback.recycleUpdateOp(removeOp);
}
// no need to swap, it is already a remove
return;
}
// now affect of add is consumed. now apply effect of first remove
if (moveOp.positionStart <= removeOp.positionStart) {
removeOp.positionStart++;
} else if (moveOp.positionStart < removeOp.positionStart + removeOp.itemCount) {
final int remaining = removeOp.positionStart + removeOp.itemCount
- moveOp.positionStart;
extraRm = mCallback.obtainUpdateOp(REMOVE, moveOp.positionStart + 1, remaining);
removeOp.itemCount = moveOp.positionStart - removeOp.positionStart;
}
// if effects of move is reverted by remove, we are done.
if (revertedMove) {
list.set(movePos, removeOp);
list.remove(removePos);
mCallback.recycleUpdateOp(moveOp);
return;
}
// now find out the new locations for move actions
if (moveIsBackwards) {
if (extraRm != null) {
if (moveOp.positionStart > extraRm.positionStart) {
moveOp.positionStart -= extraRm.itemCount;
}
if (moveOp.itemCount > extraRm.positionStart) {
moveOp.itemCount -= extraRm.itemCount;
}
}
if (moveOp.positionStart > removeOp.positionStart) {
moveOp.positionStart -= removeOp.itemCount;
}
if (moveOp.itemCount > removeOp.positionStart) {
moveOp.itemCount -= removeOp.itemCount;
}
} else {
if (extraRm != null) {
if (moveOp.positionStart >= extraRm.positionStart) {
moveOp.positionStart -= extraRm.itemCount;
}
if (moveOp.itemCount >= extraRm.positionStart) {
moveOp.itemCount -= extraRm.itemCount;
}
}
if (moveOp.positionStart >= removeOp.positionStart) {
moveOp.positionStart -= removeOp.itemCount;
}
if (moveOp.itemCount >= removeOp.positionStart) {
moveOp.itemCount -= removeOp.itemCount;
}
}
list.set(movePos, removeOp);
if (moveOp.positionStart != moveOp.itemCount) {
list.set(removePos, moveOp);
} else {
list.remove(removePos);
}
if (extraRm != null) {
list.add(movePos, extraRm);
}
| | void | swapMoveUpdate(java.util.List list, int move, android.support.v7.widget.AdapterHelper.UpdateOp moveOp, int update, android.support.v7.widget.AdapterHelper.UpdateOp updateOp)
UpdateOp extraUp1 = null;
UpdateOp extraUp2 = null;
// going in reverse, first revert the effect of add
if (moveOp.itemCount < updateOp.positionStart) {
updateOp.positionStart--;
} else if (moveOp.itemCount < updateOp.positionStart + updateOp.itemCount) {
// moved item is updated. add an update for it
updateOp.itemCount--;
extraUp1 = mCallback.obtainUpdateOp(UPDATE, moveOp.positionStart, 1);
}
// now affect of add is consumed. now apply effect of first remove
if (moveOp.positionStart <= updateOp.positionStart) {
updateOp.positionStart++;
} else if (moveOp.positionStart < updateOp.positionStart + updateOp.itemCount) {
final int remaining = updateOp.positionStart + updateOp.itemCount
- moveOp.positionStart;
extraUp2 = mCallback.obtainUpdateOp(UPDATE, moveOp.positionStart + 1, remaining);
updateOp.itemCount -= remaining;
}
list.set(update, moveOp);
if (updateOp.itemCount > 0) {
list.set(move, updateOp);
} else {
list.remove(move);
mCallback.recycleUpdateOp(updateOp);
}
if (extraUp1 != null) {
list.add(move, extraUp1);
}
if (extraUp2 != null) {
list.add(move, extraUp2);
}
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