这里同拖拽的空屏类似，只是区别判断
Workspace
@Override
public void onDrop(final DragObject d, DragOptions options) {
mDragViewVisualCenter = d.getVisualCenter(mDragViewVisualCenter);
CellLayout dropTargetLayout = mDropToLayout;
// We want the point to be mapped to the dragTarget.
if (dropTargetLayout != null) {
mapPointFromDropLayout(dropTargetLayout, mDragViewVisualCenter);
}
boolean droppedOnOriginalCell = false;
boolean snappedToNewPage = false;
boolean resizeOnDrop = false;
Runnable onCompleteRunnable = null;
if (d.dragSource != this || mDragInfo == null) {
final int[] touchXY = new int[] { (int) mDragViewVisualCenter[0],
(int) mDragViewVisualCenter[1] };
onDropExternal(touchXY, dropTargetLayout, d);
} else {
final View cell = mDragInfo.cell;
boolean droppedOnOriginalCellDuringTransition = false;
//参考拖拽空屏的处理，拖拽到hotseat回到原来的位置
boolean isCanDrop = true;
if(mLauncher.isHotseatLayout(dropTargetLayout)) {
isCanDrop = false;
}
//多增加拖拽到Hotseat的判断
if (dropTargetLayout != null && !d.cancelled && isCanDrop) {
// if (dropTargetLayout != null && !d.cancelled) {
// Move internally
boolean hasMovedLayouts = (getParentCellLayoutForView(cell) != dropTargetLayout);
boolean hasMovedIntoHotseat = mLauncher.isHotseatLayout(dropTargetLayout);
int container = hasMovedIntoHotseat ?
LauncherSettings.Favorites.CONTAINER_HOTSEAT :
LauncherSettings.Favorites.CONTAINER_DESKTOP;
int screenId = (mTargetCell[0] < 0) ?
mDragInfo.screenId : getIdForScreen(dropTargetLayout);
int spanX = mDragInfo != null ? mDragInfo.spanX : 1;
int spanY = mDragInfo != null ? mDragInfo.spanY : 1;
// First we find the cell nearest to point at which the item is
// dropped, without any consideration to whether there is an item there.
mTargetCell = findNearestArea((int) mDragViewVisualCenter[0], (int)
mDragViewVisualCenter[1], spanX, spanY, dropTargetLayout, mTargetCell);
float distance = dropTargetLayout.getDistanceFromWorkspaceCellVisualCenter(
mDragViewVisualCenter[0], mDragViewVisualCenter[1], mTargetCell);
// If the item being dropped is a shortcut and the nearest drop
// cell also contains a shortcut, then create a folder with the two shortcuts.
if (createUserFolderIfNecessary(cell, container, dropTargetLayout, mTargetCell,
distance, false, d)
|| addToExistingFolderIfNecessary(cell, dropTargetLayout, mTargetCell,
distance, d, false)) {
mLauncher.getStateManager().goToState(NORMAL, SPRING_LOADED_EXIT_DELAY);
return;
}
// Aside from the special case where we're dropping a shortcut onto a shortcut,
// we need to find the nearest cell location that is vacant
ItemInfo item = d.dragInfo;
int minSpanX = item.spanX;
int minSpanY = item.spanY;
if (item.minSpanX > 0 && item.minSpanY > 0) {
minSpanX = item.minSpanX;
minSpanY = item.minSpanY;
}
droppedOnOriginalCell = item.screenId == screenId && item.container == container
&& item.cellX == mTargetCell[0] && item.cellY == mTargetCell[1];
droppedOnOriginalCellDuringTransition = droppedOnOriginalCell && mIsSwitchingState;
// When quickly moving an item, a user may accidentally rearrange their
// workspace. So instead we move the icon back safely to its original position.
boolean returnToOriginalCellToPreventShuffling = !isFinishedSwitchingState()
&& !droppedOnOriginalCellDuringTransition && !dropTargetLayout
.isRegionVacant(mTargetCell[0], mTargetCell[1], spanX, spanY);
int[] resultSpan = new int[2];
if (returnToOriginalCellToPreventShuffling) {
mTargetCell[0] = mTargetCell[1] = -1;
} else {
mTargetCell = dropTargetLayout.performReorder((int) mDragViewVisualCenter[0],
(int) mDragViewVisualCenter[1], minSpanX, minSpanY, spanX, spanY,
cell, mTargetCell, resultSpan, CellLayout.MODE_ON_DROP);
}
boolean foundCell = mTargetCell[0] >= 0 && mTargetCell[1] >= 0;
// if the widget resizes on drop
if (foundCell && (cell instanceof AppWidgetHostView) &&
(resultSpan[0] != item.spanX || resultSpan[1] != item.spanY)) {
resizeOnDrop = true;
item.spanX = resultSpan[0];
item.spanY = resultSpan[1];
AppWidgetHostView awhv = (AppWidgetHostView) cell;
WidgetSizes.updateWidgetSizeRanges(awhv, mLauncher, resultSpan[0],
resultSpan[1]);
}
if (foundCell) {
int targetScreenIndex = getPageIndexForScreenId(screenId);
int snapScreen = getLeftmostVisiblePageForIndex(targetScreenIndex);
// On large screen devices two pages can be shown at the same time, and snap
// isn't needed if the source and target screens appear at the same time
if (snapScreen != mCurrentPage && !hasMovedIntoHotseat) {
snapToPage(snapScreen);
snappedToNewPage = true;
}
final ItemInfo info = (ItemInfo) cell.getTag();
if (hasMovedLayouts) {
// Reparent the view
CellLayout parentCell = getParentCellLayoutForView(cell);
if (parentCell != null) {
parentCell.removeView(cell);
} else if (mDragInfo.cell instanceof LauncherAppWidgetHostView) {
d.dragView.detachContentView(/* reattachToPreviousParent= */ false);
} else if (FeatureFlags.IS_STUDIO_BUILD) {
throw new NullPointerException("mDragInfo.cell has null parent");
}
addInScreen(cell, container, screenId, mTargetCell[0], mTargetCell[1],
info.spanX, info.spanY);
}
// update the item's position after drop
CellLayoutLayoutParams lp = (CellLayoutLayoutParams) cell.getLayoutParams();
lp.cellX = lp.tmpCellX = mTargetCell[0];
lp.cellY = lp.tmpCellY = mTargetCell[1];
lp.cellHSpan = item.spanX;
lp.cellVSpan = item.spanY;
lp.isLockedToGrid = true;
if (container != LauncherSettings.Favorites.CONTAINER_HOTSEAT &&
cell instanceof LauncherAppWidgetHostView) {
// We post this call so that the widget has a chance to be placed
// in its final location
onCompleteRunnable = getWidgetResizeFrameRunnable(options,
(LauncherAppWidgetHostView) cell, dropTargetLayout);
}
mLauncher.getModelWriter().modifyItemInDatabase(info, container, screenId,
lp.cellX, lp.cellY, item.spanX, item.spanY);
} else {
if (!returnToOriginalCellToPreventShuffling) {
onNoCellFound(dropTargetLayout, d.dragInfo, d.logInstanceId);
}
if (mDragInfo.cell instanceof LauncherAppWidgetHostView) {
d.dragView.detachContentView(/* reattachToPreviousParent= */ true);
}
// If we can't find a drop location, we return the item to its original position
CellLayoutLayoutParams lp = (CellLayoutLayoutParams) cell.getLayoutParams();
mTargetCell[0] = lp.cellX;
mTargetCell[1] = lp.cellY;
CellLayout layout = (CellLayout) cell.getParent().getParent();
layout.markCellsAsOccupiedForView(cell);
}
} else {
// When drag is cancelled, reattach content view back to its original parent.
if (cell instanceof LauncherAppWidgetHostView) {
d.dragView.detachContentView(/* reattachToPreviousParent= */ true);
final CellLayout cellLayout = getParentCellLayoutForView(cell);
boolean pageIsVisible = isVisible(cellLayout);
if (pageIsVisible) {
onCompleteRunnable = getWidgetResizeFrameRunnable(options,
(LauncherAppWidgetHostView) cell, cellLayout);
}
}
}
final CellLayout parent = (CellLayout) cell.getParent().getParent();
if (d.dragView.hasDrawn()) {
if (droppedOnOriginalCellDuringTransition) {
// Animate the item to its original position, while simultaneously exiting
// spring-loaded mode so the page meets the icon where it was picked up.
final RunnableList callbackList = new RunnableList();
final Runnable onCompleteCallback = onCompleteRunnable;
mLauncher.getDragController().animateDragViewToOriginalPosition(
/* onComplete= */ callbackList::executeAllAndDestroy, cell,
SPRING_LOADED.getTransitionDuration(mLauncher, true /* isToState */));
mLauncher.getStateManager().goToState(NORMAL, /* delay= */ 0,
onCompleteCallback == null
? null
: forSuccessCallback(
() -> callbackList.add(onCompleteCallback)));
mLauncher.getDropTargetBar().onDragEnd();
parent.onDropChild(cell);
return;
}
final ItemInfo info = (ItemInfo) cell.getTag();
boolean isWidget = info.itemType == LauncherSettings.Favorites.ITEM_TYPE_APPWIDGET
|| info.itemType == LauncherSettings.Favorites.ITEM_TYPE_CUSTOM_APPWIDGET;
if (isWidget && dropTargetLayout != null) {
// animate widget to a valid place
int animationType = resizeOnDrop ? ANIMATE_INTO_POSITION_AND_RESIZE :
ANIMATE_INTO_POSITION_AND_DISAPPEAR;
animateWidgetDrop(info, parent, d.dragView, null, animationType, cell, false);
} else {
int duration = snappedToNewPage ? ADJACENT_SCREEN_DROP_DURATION : -1;
mLauncher.getDragLayer().animateViewIntoPosition(d.dragView, cell, duration,
this);
}
} else {
d.deferDragViewCleanupPostAnimation = false;
cell.setVisibility(VISIBLE);
}
parent.onDropChild(cell);
mLauncher.getStateManager().goToState(NORMAL, SPRING_LOADED_EXIT_DELAY,
onCompleteRunnable == null ? null : forSuccessCallback(onCompleteRunnable));
mStatsLogManager.logger().withItemInfo(d.dragInfo).withInstanceId(d.logInstanceId)
.log(LauncherEvent.LAUNCHER_ITEM_DROP_COMPLETED);
}
if (d.stateAnnouncer != null && !droppedOnOriginalCell) {
d.stateAnnouncer.completeAction(R.string.item_moved);
}
}
效果
