| /* |
| * Copyright (C) 2010 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.contacts.list; |
| |
| import android.widget.SectionIndexer; |
| |
| import java.util.Arrays; |
| |
| /** |
| * A section indexer that is configured with precomputed section titles and |
| * their respective counts. |
| */ |
| public class ContactsSectionIndexer implements SectionIndexer { |
| |
| private final String[] mSections; |
| private final int[] mPositions; |
| private final int mCount; |
| |
| /** |
| * Constructor. |
| * |
| * @param sections a non-null array |
| * @param counts a non-null array of the same size as <code>sections</code> |
| */ |
| public ContactsSectionIndexer(String[] sections, int[] counts) { |
| if (sections == null || counts == null) { |
| throw new NullPointerException(); |
| } |
| |
| if (sections.length != counts.length) { |
| throw new IllegalArgumentException( |
| "The sections and counts arrays must have the same length"); |
| } |
| |
| // TODO process sections/counts based on current locale and/or specific section titles |
| |
| this.mSections = sections; |
| mPositions = new int[counts.length]; |
| int position = 0; |
| for (int i = 0; i < counts.length; i++) { |
| if (mSections[i] == null) { |
| mSections[i] = " "; |
| } else { |
| mSections[i] = mSections[i].trim(); |
| } |
| |
| mPositions[i] = position; |
| position += counts[i]; |
| } |
| mCount = position; |
| } |
| |
| public Object[] getSections() { |
| return mSections; |
| } |
| |
| public int getPositionForSection(int section) { |
| if (section < 0 || section >= mSections.length) { |
| return -1; |
| } |
| |
| return mPositions[section]; |
| } |
| |
| public int getSectionForPosition(int position) { |
| if (position < 0 || position >= mCount) { |
| return -1; |
| } |
| |
| int index = Arrays.binarySearch(mPositions, position); |
| |
| /* |
| * Consider this example: section positions are 0, 3, 5; the supplied |
| * position is 4. The section corresponding to position 4 starts at |
| * position 3, so the expected return value is 1. Binary search will not |
| * find 4 in the array and thus will return -insertPosition-1, i.e. -3. |
| * To get from that number to the expected value of 1 we need to negate |
| * and subtract 2. |
| */ |
| return index >= 0 ? index : -index - 2; |
| } |
| } |