src/com/android/launcher3/folder/FolderIconPreviewVerifier.java

/*
 * Copyright (C) 2017 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.folder;

import android.util.Log;

import com.android.launcher3.FolderInfo;
import com.android.launcher3.InvariantDeviceProfile;

import static com.android.launcher3.folder.ClippedFolderIconLayoutRule.MAX_NUM_ITEMS_IN_PREVIEW;

/**
 * Verifies whether an item in a Folder is displayed in the FolderIcon preview.
 */
public class FolderIconPreviewVerifier {

    private static final String TAG = "FolderPreviewVerifier";

    private final int mMaxGridCountX;
    private final int mMaxGridCountY;
    private final int mMaxItemsPerPage;
    private final int[] mGridSize = new int[] { 1, 1 };

    private int mNumItemsInFolder;
    private int mGridCountX;
    private boolean mDisplayingUpperLeftQuadrant = false;

    /**
     * Note: must call {@link #setFolderInfo(FolderInfo)} manually for verifier to work.
     */
    public FolderIconPreviewVerifier(InvariantDeviceProfile profile) {
        mMaxGridCountX = profile.numFolderColumns;
        mMaxGridCountY = profile.numFolderRows;
        mMaxItemsPerPage = mMaxGridCountX * mMaxGridCountY;
    }

    public void setFolderInfo(FolderInfo info) {
        int numItemsInFolder = info.contents.size();
        if (numItemsInFolder != mNumItemsInFolder) {
            FolderPagedView.calculateGridSize(numItemsInFolder, 0, 0, mMaxGridCountX,
                    mMaxGridCountY, mMaxItemsPerPage, mGridSize);
            mGridCountX = mGridSize[0];

            mDisplayingUpperLeftQuadrant = numItemsInFolder > MAX_NUM_ITEMS_IN_PREVIEW;
            mNumItemsInFolder = numItemsInFolder;
        }
    }

    /**
     * Returns whether the item with {@param rank} is in the default Folder icon preview.
     */
    public boolean isItemInPreview(int rank) {
        return isItemInPreview(0, rank);
    }

    /**
     * @param page The page the item is on.
     * @param rank The rank of the item.
     * @return True iff the icon is in the 2x2 upper left quadrant of the Folder.
     */
    public boolean isItemInPreview(int page, int rank) {
        if (mGridSize[0] == 1) {
            Log.w(TAG, "setFolderInfo not called before checking if item is in preview.");
        }

        // First page items are laid out such that the first 4 items are always in the upper
        // left quadrant. For all other pages, we need to check the row and col.
        if (page > 0 || mDisplayingUpperLeftQuadrant) {
            int col = rank % mGridCountX;
            int row = rank / mGridCountX;
            return col < 2 && row < 2;
        }
        return rank < MAX_NUM_ITEMS_IN_PREVIEW;
    }
}