BandSelectMatrix: Create matrix tracking location of RecycleView items and band selection.

/*

 * Copyright (C) 2015 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.documentsui;

import static org.junit.Assert.*;

import com.android.documentsui.BandSelectMatrix;

import android.graphics.Point;

import android.graphics.Rect;

import android.support.v7.widget.RecyclerView.OnScrollListener;

import android.util.SparseBooleanArray;

import org.junit.After;

import org.junit.Test;

public class BandSelectMatrixTest {

    private static final int VIEW_PADDING_PX = 5;

    private static final int CHILD_VIEW_EDGE_PX = 100;

    private static final int VIEWPORT_HEIGHT = 500;

    private static BandSelectMatrix matrix;

    private static TestHelper helper;

    private static SparseBooleanArray lastSelection;

    private static int viewWidth;

    private static void setUp(int numChildren, int numColumns) {

        helper = new TestHelper(numChildren, numColumns);

        viewWidth = VIEW_PADDING_PX + numColumns * (VIEW_PADDING_PX + CHILD_VIEW_EDGE_PX);

        matrix = new BandSelectMatrix(helper);

        matrix.addOnSelectionChangedListener(new BandSelectMatrix.OnSelectionChangedListener() {

            @Override

            public void onSelectionChanged(SparseBooleanArray updatedSelection) {

                lastSelection = updatedSelection;

            }

        });

    }

    @After

    public void tearDown() {

        matrix = null;

        helper = null;

        lastSelection = null;

    }

    @Test

    public void testSelectionLeftOfItems() {

        setUp(20, 5);

        matrix.startSelection(new Point(0, 10));

        matrix.resizeSelection(new Point(1, 11));

        assertSelected(new int[0]);

    }

    @Test

    public void testSelectionRightOfItems() {

        setUp(20, 4);

        matrix.startSelection(new Point(viewWidth - 1, 10));

        matrix.resizeSelection(new Point(viewWidth - 2, 11));

        assertSelected(new int[0]);

    }

    @Test

    public void testSelectionAboveItems() {

        setUp(20, 4);

        matrix.startSelection(new Point(10, 0));

        matrix.resizeSelection(new Point(11, 1));

        assertSelected(new int[0]);

    }

    @Test

    public void testSelectionBelowItems() {

        setUp(5, 4);

        matrix.startSelection(new Point(10, VIEWPORT_HEIGHT - 1));

        matrix.resizeSelection(new Point(11, VIEWPORT_HEIGHT - 2));

        assertSelected(new int[0]);

    }

    @Test

    public void testVerticalSelectionBetweenItems() {

        setUp(20, 4);

        matrix.startSelection(new Point(106, 0));

        matrix.resizeSelection(new Point(107, 200));

        assertSelected(new int[0]);

    }

    @Test

    public void testHorizontalSelectionBetweenItems() {

        setUp(20, 4);

        matrix.startSelection(new Point(0, 105));

        matrix.resizeSelection(new Point(200, 106));

        assertSelected(new int[0]);

    }

    @Test

    public void testGrowingAndShrinkingSelection() {

        setUp(20, 4);

        matrix.startSelection(new Point(0, 0));

        matrix.resizeSelection(new Point(5, 5));

        assertSelected(new int[] {0});

        matrix.resizeSelection(new Point(109, 109));

        assertSelected(new int[] {0});

        matrix.resizeSelection(new Point(110, 109));

        assertSelected(new int[] {0, 1});

        matrix.resizeSelection(new Point(110, 110));

        assertSelected(new int[] {0, 1, 4, 5});

        matrix.resizeSelection(new Point(214, 214));

        assertSelected(new int[] {0, 1, 4, 5});

        matrix.resizeSelection(new Point(215, 214));

        assertSelected(new int[] {0, 1, 2, 4, 5, 6});

        matrix.resizeSelection(new Point(214, 214));

        assertSelected(new int[] {0, 1, 4, 5});

        matrix.resizeSelection(new Point(110, 110));

        assertSelected(new int[] {0, 1, 4, 5});

        matrix.resizeSelection(new Point(110, 109));

        assertSelected(new int[] {0, 1});

        matrix.resizeSelection(new Point(109, 109));

        assertSelected(new int[] {0});

        matrix.resizeSelection(new Point(5, 5));

        assertSelected(new int[] {0});

        matrix.resizeSelection(new Point(0, 0));

        assertSelected(new int[0]);

    }

    @Test

    public void testSelectionMovingAroundOrigin() {

        setUp(16, 4);

        matrix.startSelection(new Point(210, 210));

        matrix.resizeSelection(new Point(viewWidth - 1, 0));

        assertSelected(new int[] {2, 3, 6, 7});

        matrix.resizeSelection(new Point(0, 0));

        assertSelected(new int[] {0, 1, 4, 5});

        matrix.resizeSelection(new Point(0, 420));

        assertSelected(new int[] {8, 9, 12, 13});

        matrix.resizeSelection(new Point(viewWidth - 1, 420));

        assertSelected(new int[] {10, 11, 14, 15});

    }

    @Test

    public void testScrollingBandSelect() {

        setUp(40, 4);

        matrix.startSelection(new Point(0, 0));

        matrix.resizeSelection(new Point(100, VIEWPORT_HEIGHT - 1));

        assertSelected(new int[] {0, 4, 8, 12, 16});

        scroll(CHILD_VIEW_EDGE_PX);

        assertSelected(new int[] {0, 4, 8, 12, 16, 20});

        matrix.resizeSelection(new Point(200, VIEWPORT_HEIGHT - 1));

        assertSelected(new int[] {0, 1, 4, 5, 8, 9, 12, 13, 16, 17, 20, 21});

        scroll(CHILD_VIEW_EDGE_PX);

        assertSelected(new int[] {0, 1, 4, 5, 8, 9, 12, 13, 16, 17, 20, 21, 24, 25});

        scroll(-2 * CHILD_VIEW_EDGE_PX);

        assertSelected(new int[] {0, 1, 4, 5, 8, 9, 12, 13, 16, 17});

        matrix.resizeSelection(new Point(100, VIEWPORT_HEIGHT - 1));

        assertSelected(new int[] {0, 4, 8, 12, 16});

    }

    private static void assertSelected(int[] selectedPositions) {

        assertEquals(selectedPositions.length, lastSelection.size());

        for (int position : selectedPositions) {

            assertTrue(lastSelection.get(position));

        }

    }

    private static void scroll(int dy) {

        assertTrue(helper.verticalOffset + VIEWPORT_HEIGHT + dy <= helper.getTotalHeight());

        helper.verticalOffset += dy;

        matrix.onScrolled(null, 0, dy);

    }

    private static final class TestHelper implements BandSelectMatrix.RecyclerViewHelper {

        public int horizontalOffset = 0;

        public int verticalOffset = 0;

        private final int mNumColumns;

        private final int mNumRows;

        private final int mNumChildren;

        public TestHelper(int numChildren, int numColumns) {

            mNumChildren = numChildren;

            mNumColumns = numColumns;

            mNumRows = (int) Math.ceil((double) numChildren / mNumColumns);

        }

        private int getTotalHeight() {

            return CHILD_VIEW_EDGE_PX * mNumRows + VIEW_PADDING_PX * (mNumRows + 1);

        }

        private int getFirstVisibleRowIndex() {

            return verticalOffset / (CHILD_VIEW_EDGE_PX + VIEW_PADDING_PX);

        }

        private int getLastVisibleRowIndex() {

            int lastVisibleRowUncapped =

                    (VIEWPORT_HEIGHT + verticalOffset - 1) / (CHILD_VIEW_EDGE_PX + VIEW_PADDING_PX);

            return Math.min(lastVisibleRowUncapped, mNumRows - 1);

        }

        private int getNumItemsInRow(int index) {

            assertTrue(index >= 0 && index < mNumRows);

            if (index == mNumRows - 1 && mNumChildren % mNumColumns != 0) {

                return mNumChildren % mNumColumns;

            }

            return mNumColumns;

        }

        @Override

        public void addOnScrollListener(OnScrollListener listener) {}

        @Override

        public void removeOnScrollListener(OnScrollListener listener) {}

        @Override

        public Point createAbsolutePoint(Point relativePoint) {

            return new Point(

                    relativePoint.x + horizontalOffset, relativePoint.y + verticalOffset);

        }

        @Override

        public int getVisibleChildCount() {

            int childCount = 0;

            for (int i = getFirstVisibleRowIndex(); i <= getLastVisibleRowIndex(); i++) {

                childCount += getNumItemsInRow(i);

            }

            return childCount;

        }

        @Override

        public int getAdapterPositionAt(int index) {

            return index + mNumColumns * (getFirstVisibleRowIndex());

        }

        @Override

        public Rect getAbsoluteRectForChildViewAt(int index) {

            int adapterPosition = getAdapterPositionAt(index);

            int rowIndex = adapterPosition / mNumColumns;

            int columnIndex = adapterPosition % mNumColumns;

            Rect rect = new Rect();

            rect.top = VIEW_PADDING_PX + rowIndex * (CHILD_VIEW_EDGE_PX + VIEW_PADDING_PX);

            rect.bottom = rect.top + CHILD_VIEW_EDGE_PX - 1;

            rect.left = VIEW_PADDING_PX + columnIndex * (CHILD_VIEW_EDGE_PX + VIEW_PADDING_PX);

            rect.right = rect.left + CHILD_VIEW_EDGE_PX - 1;

            return rect;

        }

        @Override

        public int getTotalChildCount() {

            return mNumChildren;

        }

        @Override

        public int getNumColumns() {

            return mNumColumns;

        }

        @Override

        public int getNumRows() {

            return mNumRows;

        }

    }

}

@RunWith(Suite.class)

@SuiteClasses({

        BandSelectMatrixTest.class,

        MultiSelectManager_SelectionTest.class,

        MultiSelectManagerTest.class

})