Greg Kaiser
228 lines
10 KiB
Java
228 lines
10 KiB
Java
/*
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* Copyright (C) 2023 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.launcher3.celllayout;
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import android.graphics.Rect;
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import android.view.View;
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import com.android.launcher3.CellLayout;
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import java.util.Map.Entry;
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/**
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* Contains the logic of a reorder.
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*
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* The content of this class was extracted from {@link CellLayout} and should mimic the exact
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* same behaviour.
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*/
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public class ReorderAlgorithm {
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CellLayout mCellLayout;
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public ReorderAlgorithm(CellLayout cellLayout) {
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mCellLayout = cellLayout;
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}
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/**
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* This method differs from closestEmptySpaceReorder and dropInPlaceSolution because this method
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* will move items around and will change the shape of the item if possible to try to find a
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* solution.
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*
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* When changing the size of the widget this method will try first subtracting -1 in the x
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* dimension and then subtracting -1 in the y dimension until finding a possible solution or
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* until it no longer can reduce the span.
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*
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* @param pixelX X coordinate in pixels in the screen
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* @param pixelY Y coordinate in pixels in the screen
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* @param minSpanX minimum possible horizontal span it will try to find a solution for.
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* @param minSpanY minimum possible vertical span it will try to find a solution for.
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* @param spanX horizontal cell span
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* @param spanY vertical cell span
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* @param direction direction in which it will try to push the items intersecting the desired
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* view
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* @param dragView view being dragged in reorder
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* @param decX whether it will decrease the horizontal or vertical span if it can't find a
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* solution for the current span.
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* @param solution variable to store the solution
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* @return the same solution variable
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*/
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public ItemConfiguration findReorderSolution(int pixelX, int pixelY, int minSpanX,
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int minSpanY, int spanX, int spanY, int[] direction, View dragView, boolean decX,
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ItemConfiguration solution) {
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return findReorderSolutionRecursive(pixelX, pixelY, minSpanX, minSpanY, spanX, spanY,
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direction, dragView, decX, solution);
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}
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private ItemConfiguration findReorderSolutionRecursive(int pixelX, int pixelY,
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int minSpanX, int minSpanY, int spanX, int spanY, int[] direction, View dragView,
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boolean decX, ItemConfiguration solution) {
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// Copy the current state into the solution. This solution will be manipulated as necessary.
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mCellLayout.copyCurrentStateToSolution(solution, false);
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// Copy the current occupied array into the temporary occupied array. This array will be
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// manipulated as necessary to find a solution.
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mCellLayout.getOccupied().copyTo(mCellLayout.mTmpOccupied);
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// We find the nearest cell into which we would place the dragged item, assuming there's
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// nothing in its way.
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int[] result = new int[2];
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result = mCellLayout.findNearestAreaIgnoreOccupied(pixelX, pixelY, spanX, spanY, result);
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boolean success;
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// First we try the exact nearest position of the item being dragged,
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// we will then want to try to move this around to other neighbouring positions
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success = mCellLayout.rearrangementExists(result[0], result[1], spanX, spanY, direction,
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dragView, solution);
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if (!success) {
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// We try shrinking the widget down to size in an alternating pattern, shrink 1 in
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// x, then 1 in y etc.
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if (spanX > minSpanX && (minSpanY == spanY || decX)) {
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return findReorderSolutionRecursive(pixelX, pixelY, minSpanX, minSpanY, spanX - 1,
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spanY, direction, dragView, false, solution);
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} else if (spanY > minSpanY) {
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return findReorderSolutionRecursive(pixelX, pixelY, minSpanX, minSpanY, spanX,
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spanY - 1, direction, dragView, true, solution);
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}
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solution.isSolution = false;
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} else {
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solution.isSolution = true;
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solution.cellX = result[0];
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solution.cellY = result[1];
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solution.spanX = spanX;
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solution.spanY = spanY;
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}
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return solution;
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}
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/**
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* Returns a "reorder" if there is empty space without rearranging anything.
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*
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* @param pixelX X coordinate in pixels in the screen
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* @param pixelY Y coordinate in pixels in the screen
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* @param spanX horizontal cell span
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* @param spanY vertical cell span
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* @param dragView view being dragged in reorder
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* @return the configuration that represents the found reorder
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*/
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public ItemConfiguration dropInPlaceSolution(int pixelX, int pixelY, int spanX,
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int spanY, View dragView) {
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int[] result = mCellLayout.findNearestAreaIgnoreOccupied(pixelX, pixelY, spanX, spanY,
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new int[2]);
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ItemConfiguration solution = new ItemConfiguration();
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mCellLayout.copyCurrentStateToSolution(solution, false);
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solution.isSolution = !isConfigurationRegionOccupied(
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new Rect(result[0], result[1], result[0] + spanX, result[1] + spanY),
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solution,
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dragView
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);
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if (!solution.isSolution) {
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return solution;
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}
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solution.cellX = result[0];
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solution.cellY = result[1];
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solution.spanX = spanX;
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solution.spanY = spanY;
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return solution;
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}
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private boolean isConfigurationRegionOccupied(Rect region,
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ItemConfiguration configuration, View ignoreView) {
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return configuration.map.entrySet()
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.stream()
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.filter(entry -> entry.getKey() != ignoreView)
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.map(Entry::getValue)
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.anyMatch(cellAndSpan -> region.intersect(cellAndSpan.cellX, cellAndSpan.cellY,
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cellAndSpan.cellX + cellAndSpan.spanX,
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cellAndSpan.cellY + cellAndSpan.spanY));
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}
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/**
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* Returns a "reorder" where we simply drop the item in the closest empty space, without moving
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* any other item in the way.
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*
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* @param pixelX X coordinate in pixels in the screen
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* @param pixelY Y coordinate in pixels in the screen
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* @param spanX horizontal cell span
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* @param spanY vertical cell span
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* @return the configuration that represents the found reorder
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*/
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public ItemConfiguration closestEmptySpaceReorder(int pixelX, int pixelY,
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int minSpanX, int minSpanY, int spanX, int spanY) {
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ItemConfiguration solution = new ItemConfiguration();
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int[] result = new int[2];
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int[] resultSpan = new int[2];
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mCellLayout.findNearestVacantArea(pixelX, pixelY, minSpanX, minSpanY, spanX, spanY, result,
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resultSpan);
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if (result[0] >= 0 && result[1] >= 0) {
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mCellLayout.copyCurrentStateToSolution(solution, false);
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solution.cellX = result[0];
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solution.cellY = result[1];
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solution.spanX = resultSpan[0];
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solution.spanY = resultSpan[1];
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solution.isSolution = true;
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} else {
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solution.isSolution = false;
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}
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return solution;
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}
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/**
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* When the user drags an Item in the workspace sometimes we need to move the items already in
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* the workspace to make space for the new item, this function return a solution for that
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* reorder.
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*
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* @param pixelX X coordinate in the screen of the dragView in pixels
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* @param pixelY Y coordinate in the screen of the dragView in pixels
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* @param minSpanX minimum horizontal span the item can be shrunk to
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* @param minSpanY minimum vertical span the item can be shrunk to
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* @param spanX occupied horizontal span
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* @param spanY occupied vertical span
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* @param dragView the view of the item being draged
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* @return returns a solution for the given parameters, the solution contains all the icons and
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* the locations they should be in the given solution.
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*/
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public ItemConfiguration calculateReorder(int pixelX, int pixelY, int minSpanX,
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int minSpanY, int spanX, int spanY, View dragView) {
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mCellLayout.getDirectionVectorForDrop(pixelX, pixelY, spanX, spanY, dragView,
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mCellLayout.mDirectionVector);
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ItemConfiguration dropInPlaceSolution = dropInPlaceSolution(pixelX, pixelY, spanX, spanY,
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dragView);
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// Find a solution involving pushing / displacing any items in the way
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ItemConfiguration swapSolution = findReorderSolution(pixelX, pixelY, minSpanX,
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minSpanY, spanX, spanY, mCellLayout.mDirectionVector, dragView, true,
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new ItemConfiguration());
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// We attempt the approach which doesn't shuffle views at all
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ItemConfiguration closestSpaceSolution = closestEmptySpaceReorder(pixelX, pixelY, minSpanX,
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minSpanY, spanX, spanY);
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// If the reorder solution requires resizing (shrinking) the item being dropped, we instead
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// favor a solution in which the item is not resized, but
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if (swapSolution.isSolution && swapSolution.area() >= closestSpaceSolution.area()) {
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return swapSolution;
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} else if (closestSpaceSolution.isSolution) {
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return closestSpaceSolution;
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} else if (dropInPlaceSolution.isSolution) {
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return dropInPlaceSolution;
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}
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return null;
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}
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}
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