Simulating a split screen CellLayout using one CellLayout

Test: atest ReorderWidget
Fix: 188081026
Change-Id: I8eda5f77c11dc2625ae1f028d07539c28018fb55

src/com/android/launcher3/MultipageCellLayout.java

@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.launcher3;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Rect;
+import android.graphics.drawable.Drawable;
+import android.util.AttributeSet;
+import android.view.View;
+
+import com.android.launcher3.celllayout.CellLayoutLayoutParams;
+import com.android.launcher3.util.CellAndSpan;
+import com.android.launcher3.util.GridOccupancy;
+
+import java.util.function.Supplier;
+
+/**
+ * CellLayout that simulates a split in the middle for use in foldable devices.
+ */
+public class MultipageCellLayout extends CellLayout {
+
+    private final Drawable mLeftBackground;
+    private final Drawable mRightBackground;
+
+    private View mSeam;
+
+    public MultipageCellLayout(Context context) {
+        this(context, null);
+    }
+
+    public MultipageCellLayout(Context context, AttributeSet attrs) {
+        this(context, attrs, 0);
+    }
+
+    public MultipageCellLayout(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        mLeftBackground = getContext().getDrawable(R.drawable.bg_celllayout);
+        mLeftBackground.setCallback(this);
+        mLeftBackground.setAlpha(0);
+
+        mRightBackground = getContext().getDrawable(R.drawable.bg_celllayout);
+        mRightBackground.setCallback(this);
+        mRightBackground.setAlpha(0);
+
+        DeviceProfile deviceProfile = mActivity.getDeviceProfile();
+
+        mCountX = deviceProfile.inv.numColumns * 2;
+        mCountY = deviceProfile.inv.numRows;
+        mSeam = new View(getContext());
+        setGridSize(mCountX, mCountY);
+    }
+
+    @Override
+    ItemConfiguration closestEmptySpaceReorder(int pixelX, int pixelY, int minSpanX, int minSpanY,
+            int spanX, int spanY) {
+        return simulateSeam(
+                () -> super.closestEmptySpaceReorder(pixelX, pixelY, minSpanX, minSpanY, spanX,
+                        spanY));
+    }
+
+    @Override
+    protected ItemConfiguration findReorderSolution(int pixelX, int pixelY, int minSpanX,
+            int minSpanY, int spanX, int spanY, int[] direction, View dragView, boolean decX,
+            ItemConfiguration solution) {
+        return simulateSeam(
+                () -> super.findReorderSolution(pixelX, pixelY, minSpanX, minSpanY, spanX, spanY,
+                        direction, dragView, decX, solution));
+    }
+
+    @Override
+    public ItemConfiguration dropInPlaceSolution(int pixelX, int pixelY, int spanX, int spanY,
+            View dragView) {
+        return simulateSeam(
+                () -> super.dropInPlaceSolution(pixelX, pixelY, spanX, spanY, dragView));
+    }
+
+    protected ItemConfiguration simulateSeam(Supplier<ItemConfiguration> f) {
+        CellLayoutLayoutParams lp = new CellLayoutLayoutParams(mCountX / 2, 0, 1, mCountY);
+        lp.canReorder = false;
+        mCountX++;
+        mShortcutsAndWidgets.addViewInLayout(mSeam, lp);
+        GridOccupancy auxGrid = mOccupied;
+        mOccupied = createGridOccupancy();
+        mTmpOccupied = new GridOccupancy(mCountX, mCountY);
+
+        ItemConfiguration res = removeSeamFromSolution(f.get());
+
+        mCountX--;
+        mShortcutsAndWidgets.removeViewInLayout(mSeam);
+        mOccupied = auxGrid;
+        mTmpOccupied = new GridOccupancy(mCountX, mCountY);
+        return res;
+    }
+
+    private ItemConfiguration removeSeamFromSolution(ItemConfiguration solution) {
+        solution.map.forEach((view, cell) -> cell.cellX = cell.cellX > mCountX / 2
+                ? cell.cellX - 1 : cell.cellX);
+        solution.cellX = solution.cellX > mCountX / 2 ? solution.cellX - 1 : solution.cellX;
+        return solution;
+    }
+
+    GridOccupancy createGridOccupancy() {
+        GridOccupancy grid = new GridOccupancy(mCountX, mCountY);
+        for (int i = 0; i < mShortcutsAndWidgets.getChildCount(); i++) {
+            View view = mShortcutsAndWidgets.getChildAt(i);
+            CellLayoutLayoutParams lp = (CellLayoutLayoutParams) view.getLayoutParams();
+            int seamOffset = lp.getCellX() >= mCountX / 2 && lp.canReorder ? 1 : 0;
+            grid.markCells(lp.getCellX() + seamOffset, lp.getCellY(), lp.cellHSpan, lp.cellVSpan,
+                    true);
+        }
+        return grid;
+    }
+
+    @Override
+    protected void copyCurrentStateToSolution(ItemConfiguration solution, boolean temp) {
+        int childCount = mShortcutsAndWidgets.getChildCount();
+        for (int i = 0; i < childCount; i++) {
+            View child = mShortcutsAndWidgets.getChildAt(i);
+            CellLayoutLayoutParams lp = (CellLayoutLayoutParams) child.getLayoutParams();
+            int seamOffset = lp.getCellX() >= mCountX / 2 && lp.canReorder ? 1 : 0;
+            CellAndSpan c = new CellAndSpan(lp.getCellX() + seamOffset, lp.getCellY(), lp.cellHSpan,
+                    lp.cellVSpan);
+            solution.add(child, c);
+        }
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        if (mLeftBackground.getAlpha() > 0) {
+            mLeftBackground.setState(mBackground.getState());
+            mLeftBackground.draw(canvas);
+        }
+        if (mRightBackground.getAlpha() > 0) {
+            mRightBackground.setState(mBackground.getState());
+            mRightBackground.draw(canvas);
+        }
+
+        super.onDraw(canvas);
+    }
+
+    @Override
+    protected void updateBgAlpha() {
+        mLeftBackground.setAlpha((int) (mSpringLoadedProgress * 255));
+        mRightBackground.setAlpha((int) (mSpringLoadedProgress * 255));
+    }
+
+    @Override
+    protected void onLayout(boolean changed, int l, int t, int r, int b) {
+        super.onLayout(changed, l, t, r, b);
+        Rect rect = mBackground.getBounds();
+        mLeftBackground.setBounds(rect.left, rect.top, rect.right / 2 - 20, rect.bottom);
+        mRightBackground.setBounds(rect.right / 2 + 20, rect.top, rect.right, rect.bottom);
+    }
+}