Add two extra empty pages on two panel launcher home

Add a new screen ID for the second extra empty page
and add that new screen as well when the existing
extra empty page is added so that users can put items
on both sides of Workspace.

Test: manual
Bug: 196376162
Change-Id: I0b4f2e818407a10d8a7c032788a7bd7a61267779

src/com/android/launcher3/Launcher.java

@@ -871,11 +871,11 @@ public class Launcher extends StatefulActivity<LauncherState> implements Launche
         if (dropLayout == null) {
             // it's possible that the add screen was removed because it was
             // empty and a re-bind occurred
-            mWorkspace.addExtraEmptyScreen();
-            return mWorkspace.commitExtraEmptyScreen();
-        } else {
-            return screenId;
+            mWorkspace.addExtraEmptyScreens();
+            IntSet emptyPagesAdded = mWorkspace.commitExtraEmptyScreens();
+            return emptyPagesAdded.isEmpty() ? -1 : emptyPagesAdded.getArray().get(0);
         }
+        return screenId;
     }
 
     @Thunk
@@ -2175,7 +2175,7 @@ public class Launcher extends StatefulActivity<LauncherState> implements Launche
             orderedScreenIds.add(firstScreenPosition, Workspace.FIRST_SCREEN_ID);
         } else if (!FeatureFlags.QSB_ON_FIRST_SCREEN && orderedScreenIds.isEmpty()) {
             // If there are no screens, we need to have an empty screen
-            mWorkspace.addExtraEmptyScreen();
+            mWorkspace.addExtraEmptyScreens();
         }
         bindAddScreens(orderedScreenIds);
 
@@ -2190,17 +2190,7 @@ public class Launcher extends StatefulActivity<LauncherState> implements Launche
             // Some empty pages might have been removed while the phone was in a single panel
             // mode, so we want to add those empty pages back.
             IntSet screenIds = IntSet.wrap(orderedScreenIds);
-            for (int i = 0; i < orderedScreenIds.size(); i++) {
-                int screenId = orderedScreenIds.get(i);
-                // Don't add the page pair if the page is the last one and if the pair is on the
-                // right, because that would cause a bug when adding new pages.
-                // TODO: (b/196376162) remove this when the new screen id logic is fixed for two
-                //  panel in Workspace::commitExtraEmptyScreen
-                if (i == orderedScreenIds.size() - 1 && screenId % 2 == 0) {
-                    continue;
-                }
-                screenIds.add(mWorkspace.getPagePair(screenId));
-            }
+            orderedScreenIds.forEach(screenId -> screenIds.add(mWorkspace.getPagePair(screenId)));
             orderedScreenIds = screenIds.getArray();
         }
 

src/com/android/launcher3/Workspace.java

@@ -125,6 +125,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import java.util.function.Consumer;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
@@ -642,18 +643,35 @@ public class Workspace extends PagedView<WorkspacePageIndicator>
         boolean childOnFinalScreen = false;
 
         if (mDragSourceInternal != null) {
+            int dragSourceChildCount = mDragSourceInternal.getChildCount();
+
+            if (isTwoPanelEnabled()) {
+                int pagePairScreenId = getPagePair(dragObject.dragInfo.screenId);
+                CellLayout pagePair = mWorkspaceScreens.get(pagePairScreenId);
+                if (pagePair == null) {
+                    // TODO: after http://b/198820019 is fixed, remove this
+                    throw new IllegalStateException("Page pair is null, "
+                            + "dragScreenId: " + dragObject.dragInfo.screenId
+                            + ", pagePairScreenId: " + pagePairScreenId
+                            + ", mScreenOrder: " + mScreenOrder.toConcatString()
+                    );
+                }
+                dragSourceChildCount += pagePair.getShortcutsAndWidgets().getChildCount();
+            }
+
             // When the drag view content is a LauncherAppWidgetHostView, we should increment the
             // drag source child count by 1 because the widget in drag has been detached from its
             // original parent, ShortcutAndWidgetContainer, and reattached to the DragView.
-            int dragSourceChildCount =
-                    dragObject.dragView.getContentView() instanceof LauncherAppWidgetHostView
-                            ? mDragSourceInternal.getChildCount() + 1
-                            : mDragSourceInternal.getChildCount();
+            if (dragObject.dragView.getContentView() instanceof LauncherAppWidgetHostView) {
+                dragSourceChildCount++;
+            }
+
             if (dragSourceChildCount == 1) {
                 lastChildOnScreen = true;
             }
             CellLayout cl = (CellLayout) mDragSourceInternal.getParent();
-            if (indexOfChild(cl) == getChildCount() - 1) {
+            if (getLeftmostVisiblePageForIndex(indexOfChild(cl))
+                    == getLeftmostVisiblePageForIndex(getPageCount() - 1)) {
                 childOnFinalScreen = true;
             }
         }
@@ -662,40 +680,83 @@ public class Workspace extends PagedView<WorkspacePageIndicator>
         if (lastChildOnScreen && childOnFinalScreen) {
             return;
         }
-        if (!mWorkspaceScreens.containsKey(EXTRA_EMPTY_SCREEN_ID)) {
-            insertNewWorkspaceScreen(EXTRA_EMPTY_SCREEN_ID);
+
+        forEachExtraEmptyPageId(extraEmptyPageId -> {
+            if (!mWorkspaceScreens.containsKey(extraEmptyPageId)) {
+                insertNewWorkspaceScreen(extraEmptyPageId);
+            }
+        });
+    }
+
+    /**
+     * Inserts extra empty pages to the end of the existing workspaces.
+     * Usually we add one extra empty screen, but when two panel home is enabled we add
+     * two extra screens.
+     **/
+    public void addExtraEmptyScreens() {
+        forEachExtraEmptyPageId(extraEmptyPageId -> {
+            if (!mWorkspaceScreens.containsKey(extraEmptyPageId)) {
+                insertNewWorkspaceScreen(extraEmptyPageId);
+            }
+        });
+    }
+
+    /**
+     * Calls the consumer with all the necessary extra empty page IDs.
+     * On a normal one panel Workspace that means only EXTRA_EMPTY_SCREEN_ID,
+     * but in a two panel scenario this also includes EXTRA_EMPTY_SCREEN_SECOND_ID.
+     */
+    private void forEachExtraEmptyPageId(Consumer<Integer> callback) {
+        callback.accept(EXTRA_EMPTY_SCREEN_ID);
+        if (isTwoPanelEnabled()) {
+            callback.accept(EXTRA_EMPTY_SCREEN_SECOND_ID);
         }
     }
 
-    public boolean addExtraEmptyScreen() {
-        if (!mWorkspaceScreens.containsKey(EXTRA_EMPTY_SCREEN_ID)) {
-            insertNewWorkspaceScreen(EXTRA_EMPTY_SCREEN_ID);
-            return true;
-        }
-        return false;
-    }
-
+    /**
+     * If two panel home is enabled we convert the last two screens that are visible at the same
+     * time. In other cases we only convert the last page.
+     */
     private void convertFinalScreenToEmptyScreenIfNecessary() {
         if (mLauncher.isWorkspaceLoading()) {
             // Invalid and dangerous operation if workspace is loading
             return;
         }
 
-        if (hasExtraEmptyScreen() || mScreenOrder.size() == 0) return;
-        int finalScreenId = mScreenOrder.get(mScreenOrder.size() - 1);
+        int panelCount = getPanelCount();
+        if (hasExtraEmptyScreens() || mScreenOrder.size() < panelCount) {
+            return;
+        }
 
-        CellLayout finalScreen = mWorkspaceScreens.get(finalScreenId);
+        SparseArray<CellLayout> finalScreens = new SparseArray<>();
 
-        // If the final screen is empty, convert it to the extra empty screen
-        if (finalScreen != null
-                && finalScreen.getShortcutsAndWidgets().getChildCount() == 0
-                && !finalScreen.isDropPending()) {
-            mWorkspaceScreens.remove(finalScreenId);
-            mScreenOrder.removeValue(finalScreenId);
+        int pageCount = mScreenOrder.size();
+        // First we add the last page(s) to the finalScreens collection. The number of final pages
+        // depends on the panel count.
+        for (int pageIndex = pageCount - panelCount; pageIndex < pageCount; pageIndex++) {
+            int screenId = mScreenOrder.get(pageIndex);
+            CellLayout screen = mWorkspaceScreens.get(screenId);
+            if (screen == null || screen.getShortcutsAndWidgets().getChildCount() != 0
+                    || screen.isDropPending()) {
+                // Final screen doesn't exist or it isn't empty or there's a pending drop
+                return;
+            }
+            finalScreens.append(screenId, screen);
+        }
 
-            // if this is the last screen, convert it to the empty screen
-            mWorkspaceScreens.put(EXTRA_EMPTY_SCREEN_ID, finalScreen);
-            mScreenOrder.add(EXTRA_EMPTY_SCREEN_ID);
+        // Then we remove the final screens from the collections (but not from the view hierarchy)
+        // and we store them as extra empty screens.
+        for (int i = 0; i < finalScreens.size(); i++) {
+            int screenId = finalScreens.keyAt(i);
+            CellLayout screen = finalScreens.get(screenId);
+
+            mWorkspaceScreens.remove(screenId);
+            mScreenOrder.removeValue(screenId);
+
+            int newScreenId = mWorkspaceScreens.containsKey(EXTRA_EMPTY_SCREEN_ID)
+                    ? EXTRA_EMPTY_SCREEN_SECOND_ID : EXTRA_EMPTY_SCREEN_ID;
+            mWorkspaceScreens.put(newScreenId, screen);
+            mScreenOrder.add(newScreenId);
         }
     }
 
@@ -703,6 +764,23 @@ public class Workspace extends PagedView<WorkspacePageIndicator>
         removeExtraEmptyScreenDelayed(0, stripEmptyScreens, null);
     }
 
+    /**
+     * The purpose of this method is to remove empty pages from Workspace.
+     * Empty page(s) from the end of mWorkspaceScreens will always be removed. The pages with
+     * ID = Workspace.EXTRA_EMPTY_SCREEN_IDS will be removed if there are other non-empty pages.
+     * If there are no more non-empty pages left, extra empty page(s) will either stay or get added.
+     *
+     * If stripEmptyScreens is true, all empty pages (not just the ones on the end) will be removed
+     * from the Workspace, and if there are no more pages left then extra empty page(s) will be
+     * added.
+     *
+     * The number of extra empty pages is equal to what getPanelCount() returns.
+     *
+     * After the method returns the possible pages are:
+     * stripEmptyScreens = true : [non-empty pages, extra empty page(s) alone]
+     * stripEmptyScreens = false : [non-empty pages, empty pages (not in the end),
+     *                             extra empty page(s) alone]
+     */
     public void removeExtraEmptyScreenDelayed(
             int delay, boolean stripEmptyScreens, Runnable onComplete) {
         if (mLauncher.isWorkspaceLoading()) {
@@ -716,18 +794,26 @@ public class Workspace extends PagedView<WorkspacePageIndicator>
             return;
         }
 
+        // First we convert the last page to an extra page if the last page is empty
+        // and we don't already have an extra page.
         convertFinalScreenToEmptyScreenIfNecessary();
-        if (hasExtraEmptyScreen()) {
-            removeView(mWorkspaceScreens.get(EXTRA_EMPTY_SCREEN_ID));
+        // Then we remove the extra page(s) if they are not the only pages left in Workspace.
+        if (hasExtraEmptyScreens()) {
+            forEachExtraEmptyPageId(extraEmptyPageId -> {
+                removeView(mWorkspaceScreens.get(extraEmptyPageId));
+                mWorkspaceScreens.remove(extraEmptyPageId);
+                mScreenOrder.removeValue(extraEmptyPageId);
+            });
+
             setCurrentPage(getNextPage());
-            mWorkspaceScreens.remove(EXTRA_EMPTY_SCREEN_ID);
-            mScreenOrder.removeValue(EXTRA_EMPTY_SCREEN_ID);
 
             // Update the page indicator to reflect the removed page.
             showPageIndicatorAtCurrentScroll();
         }
 
         if (stripEmptyScreens) {
+            // This will remove all empty pages from the Workspace. If there are no more pages left,
+            // it will add extra page(s) so that users can put items on at least one page.
             stripEmptyScreens();
         }
 
@@ -736,27 +822,56 @@ public class Workspace extends PagedView<WorkspacePageIndicator>
         }
     }
 
-    public boolean hasExtraEmptyScreen() {
-        return mWorkspaceScreens.containsKey(EXTRA_EMPTY_SCREEN_ID) && getChildCount() > 1;
+    public boolean hasExtraEmptyScreens() {
+        return mWorkspaceScreens.containsKey(EXTRA_EMPTY_SCREEN_ID)
+                && getChildCount() > getPanelCount()
+                && (!isTwoPanelEnabled()
+                || mWorkspaceScreens.containsKey(EXTRA_EMPTY_SCREEN_SECOND_ID));
     }
 
-    public int commitExtraEmptyScreen() {
+    /**
+     *  Commits the extra empty pages then returns the screen ids of those new screens.
+     *  Usually there's only one extra empty screen, but when two panel home is enabled we commit
+     *  two extra screens.
+     *
+     *  Returns an empty IntSet in case we cannot commit any new screens.
+     */
+    public IntSet commitExtraEmptyScreens() {
         if (mLauncher.isWorkspaceLoading()) {
             // Invalid and dangerous operation if workspace is loading
-            return -1;
+            return new IntSet();
         }
 
-        CellLayout cl = mWorkspaceScreens.get(EXTRA_EMPTY_SCREEN_ID);
-        mWorkspaceScreens.remove(EXTRA_EMPTY_SCREEN_ID);
-        mScreenOrder.removeValue(EXTRA_EMPTY_SCREEN_ID);
+        IntSet extraEmptyPageIds = new IntSet();
+        forEachExtraEmptyPageId(extraEmptyPageId ->
+                extraEmptyPageIds.add(commitExtraEmptyScreen(extraEmptyPageId)));
 
-        int newId = LauncherSettings.Settings.call(getContext().getContentResolver(),
+        return extraEmptyPageIds;
+    }
+
+    private int commitExtraEmptyScreen(int emptyScreenId) {
+        CellLayout cl = mWorkspaceScreens.get(emptyScreenId);
+        mWorkspaceScreens.remove(emptyScreenId);
+        mScreenOrder.removeValue(emptyScreenId);
+
+        int newScreenId = LauncherSettings.Settings.call(getContext().getContentResolver(),
                 LauncherSettings.Settings.METHOD_NEW_SCREEN_ID)
                 .getInt(LauncherSettings.Settings.EXTRA_VALUE);
-        mWorkspaceScreens.put(newId, cl);
-        mScreenOrder.add(newId);
 
-        return newId;
+
+        // When two panel home is enabled and the last page (the page on the right) doesn't
+        // have any items, then Launcher database doesn't know about this page because it was added
+        // by Launcher::bindAddScreens but wasn't inserted into the database. LauncherSettings's
+        // generate new screen ID method will return the ID for the left page,
+        // so we need to increment it.
+        if (isTwoPanelEnabled() && emptyScreenId == EXTRA_EMPTY_SCREEN_ID && newScreenId % 2 == 1) {
+            newScreenId++;
+        }
+
+        mWorkspaceScreens.put(newScreenId, cl);
+        mScreenOrder.add(newScreenId);
+
+        return newScreenId;
     }
 
     @Override
@@ -857,9 +972,10 @@ public class Workspace extends PagedView<WorkspacePageIndicator>
             }
         }
 
-        // We enforce at least one page to add new items to. In the case that we remove the last
-        // such screen, we convert the last screen to the empty screen
-        int minScreens = 1;
+        // We enforce at least one page (two pages on two panel home) to add new items to.
+        // In the case that we remove the last such screen(s), we convert the last screen(s)
+        // to the empty screen(s)
+        int minScreens = getPanelCount();
 
         int pageShift = 0;
         for (int i = 0; i < removeScreens.size(); i++) {
@@ -869,14 +985,21 @@ public class Workspace extends PagedView<WorkspacePageIndicator>
             mScreenOrder.removeValue(id);
 
             if (getChildCount() > minScreens) {
+                // If this isn't the last page, just remove it
                 if (indexOfChild(cl) < currentPage) {
                     pageShift++;
                 }
                 removeView(cl);
             } else {
-                // if this is the last screen, convert it to the empty screen
-                mWorkspaceScreens.put(EXTRA_EMPTY_SCREEN_ID, cl);
-                mScreenOrder.add(EXTRA_EMPTY_SCREEN_ID);
+                // The last page(s) should be converted into extra empty page(s)
+                int extraScreenId = isTwoPanelEnabled() && id % 2 == 1
+                        // This is the right panel in a two panel scenario
+                        ? EXTRA_EMPTY_SCREEN_SECOND_ID
+                        // This is either the last screen in a one panel scenario, or the left panel
+                        // in a two panel scenario when there are only two empty pages left
+                        : EXTRA_EMPTY_SCREEN_ID;
+                mWorkspaceScreens.put(extraScreenId, cl);
+                mScreenOrder.add(extraScreenId);
             }
         }
 
@@ -1646,8 +1769,8 @@ public class Workspace extends PagedView<WorkspacePageIndicator>
         }
 
         int screenId = getIdForScreen(dropTargetLayout);
-        if (screenId == EXTRA_EMPTY_SCREEN_ID) {
-            commitExtraEmptyScreen();
+        if (Workspace.EXTRA_EMPTY_SCREEN_IDS.contains(screenId)) {
+            commitExtraEmptyScreens();
         }
 
         return true;

src/com/android/launcher3/WorkspaceLayoutManager.java

@@ -23,6 +23,7 @@ import com.android.launcher3.folder.Folder;
 import com.android.launcher3.folder.FolderIcon;
 import com.android.launcher3.model.data.ItemInfo;
 import com.android.launcher3.touch.ItemLongClickListener;
+import com.android.launcher3.util.IntSet;
 
 public interface WorkspaceLayoutManager {
 
@@ -30,6 +31,12 @@ public interface WorkspaceLayoutManager {
 
     // The screen id used for the empty screen always present at the end.
     int EXTRA_EMPTY_SCREEN_ID = -201;
+    // The screen id used for the second empty screen always present at the end for two panel home.
+    int EXTRA_EMPTY_SCREEN_SECOND_ID = -200;
+    // The screen ids used for the empty screens at the end of the workspaces.
+    IntSet EXTRA_EMPTY_SCREEN_IDS =
+            IntSet.wrap(EXTRA_EMPTY_SCREEN_ID, EXTRA_EMPTY_SCREEN_SECOND_ID);
+
     // The is the first screen. It is always present, even if its empty.
     int FIRST_SCREEN_ID = 0;
     // This is the second page. On two panel home it is always present, even if its empty.
@@ -81,9 +88,9 @@ public interface WorkspaceLayoutManager {
                 return;
             }
         }
-        if (screenId == EXTRA_EMPTY_SCREEN_ID) {
+        if (EXTRA_EMPTY_SCREEN_IDS.contains(screenId)) {
             // This should never happen
-            throw new RuntimeException("Screen id should not be EXTRA_EMPTY_SCREEN_ID");
+            throw new RuntimeException("Screen id should not be extra empty screen: " + screenId);
         }
 
         final CellLayout layout;

src/com/android/launcher3/accessibility/LauncherAccessibilityDelegate.java

@@ -45,6 +45,7 @@ import com.android.launcher3.popup.ArrowPopup;
 import com.android.launcher3.popup.PopupContainerWithArrow;
 import com.android.launcher3.touch.ItemLongClickListener;
 import com.android.launcher3.util.IntArray;
+import com.android.launcher3.util.IntSet;
 import com.android.launcher3.util.ShortcutUtil;
 import com.android.launcher3.util.Thunk;
 import com.android.launcher3.views.OptionsPopupView;
@@ -221,6 +222,9 @@ public class LauncherAccessibilityDelegate extends AccessibilityDelegate impleme
         } else if (action == ADD_TO_WORKSPACE) {
             final int[] coordinates = new int[2];
             final int screenId = findSpaceOnWorkspace(item, coordinates);
+            if (screenId == -1) {
+                return false;
+            }
             mLauncher.getStateManager().goToState(NORMAL, true, forSuccessCallback(() -> {
                 if (item instanceof AppInfo) {
                     WorkspaceItemInfo info = ((AppInfo) item).makeWorkspaceItem();
@@ -250,6 +254,9 @@ public class LauncherAccessibilityDelegate extends AccessibilityDelegate impleme
 
             final int[] coordinates = new int[2];
             final int screenId = findSpaceOnWorkspace(item, coordinates);
+            if (screenId == -1) {
+                return false;
+            }
             mLauncher.getModelWriter().moveItemInDatabase(info,
                     Favorites.CONTAINER_DESKTOP,
                     screenId, coordinates[0], coordinates[1]);
@@ -489,8 +496,14 @@ public class LauncherAccessibilityDelegate extends AccessibilityDelegate impleme
             return screenId;
         }
 
-        workspace.addExtraEmptyScreen();
-        screenId = workspace.commitExtraEmptyScreen();
+        workspace.addExtraEmptyScreens();
+        IntSet emptyScreenIds = workspace.commitExtraEmptyScreens();
+        if (emptyScreenIds.isEmpty()) {
+            // Couldn't create extra empty screens for some reason (e.g. Workspace is loading)
+            return -1;
+        }
+
+        screenId = emptyScreenIds.getArray().get(0);
         layout = workspace.getScreenWithId(screenId);
         found = layout.findCellForSpan(outCoordinates, info.spanX, info.spanY);
 

src/com/android/launcher3/accessibility/ShortcutMenuAccessibilityDelegate.java

@@ -68,6 +68,9 @@ public class ShortcutMenuAccessibilityDelegate extends LauncherAccessibilityDele
             final WorkspaceItemInfo info = ((DeepShortcutView) host.getParent()).getFinalInfo();
             final int[] coordinates = new int[2];
             final int screenId = findSpaceOnWorkspace(item, coordinates);
+            if (screenId == -1) {
+                return false;
+            }
             mLauncher.getStateManager().goToState(NORMAL, true, forSuccessCallback(() -> {
                 mLauncher.getModelWriter().addItemToDatabase(info,
                         LauncherSettings.Favorites.CONTAINER_DESKTOP,

src/com/android/launcher3/model/data/ItemInfo.java

@@ -232,9 +232,9 @@ public class ItemInfo {
      * Write the fields of this item to the DB
      */
     public void onAddToDatabase(ContentWriter writer) {
-        if (screenId == Workspace.EXTRA_EMPTY_SCREEN_ID) {
+        if (Workspace.EXTRA_EMPTY_SCREEN_IDS.contains(screenId)) {
             // We should never persist an item on the extra empty screen.
-            throw new RuntimeException("Screen id should not be EXTRA_EMPTY_SCREEN_ID");
+            throw new RuntimeException("Screen id should not be extra empty screen: " + screenId);
         }
 
         writeToValues(writer);

src/com/android/launcher3/util/WallpaperOffsetInterpolator.java

@@ -150,8 +150,8 @@ public class WallpaperOffsetInterpolator extends BroadcastReceiver {
      */
     private int getNumPagesExcludingEmpty() {
         int numOfPages = mWorkspace.getChildCount();
-        if (numOfPages >= MIN_PARALLAX_PAGE_SPAN && mWorkspace.hasExtraEmptyScreen()) {
-            return numOfPages - 1;
+        if (numOfPages >= MIN_PARALLAX_PAGE_SPAN && mWorkspace.hasExtraEmptyScreens()) {
+            return numOfPages - mWorkspace.getPanelCount();
         } else {
             return numOfPages;
         }