1 /* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.contacts.list; 18 19 import android.text.TextUtils; 20 import android.widget.SectionIndexer; 21 22 import java.util.Arrays; 23 24 /** 25 * A section indexer that is configured with precomputed section titles and 26 * their respective counts. 27 */ 28 public class ContactsSectionIndexer implements SectionIndexer { 29 30 protected static final String BLANK_HEADER_STRING = "\u2026"; // ellipsis 31 32 private String[] mSections; 33 private int[] mPositions; 34 private int mCount; 35 36 /** 37 * Constructor. 38 * 39 * @param sections a non-null array 40 * @param counts a non-null array of the same size as <code>sections</code> 41 */ ContactsSectionIndexer(String[] sections, int[] counts)42 public ContactsSectionIndexer(String[] sections, int[] counts) { 43 if (sections == null || counts == null) { 44 throw new NullPointerException(); 45 } 46 47 if (sections.length != counts.length) { 48 throw new IllegalArgumentException( 49 "The sections and counts arrays must have the same length"); 50 } 51 52 // TODO process sections/counts based on current locale and/or specific section titles 53 54 this.mSections = sections; 55 mPositions = new int[counts.length]; 56 int position = 0; 57 for (int i = 0; i < counts.length; i++) { 58 // Enforce that there will be no null or empty sections. 59 if (TextUtils.isEmpty(mSections[i])) { 60 mSections[i] = BLANK_HEADER_STRING; 61 } else if (!mSections[i].equals(BLANK_HEADER_STRING)) { 62 mSections[i] = mSections[i].trim(); 63 } 64 65 mPositions[i] = position; 66 position += counts[i]; 67 } 68 mCount = position; 69 } 70 getSections()71 public Object[] getSections() { 72 return mSections; 73 } 74 getPositions()75 public int[] getPositions() { 76 return mPositions; 77 } 78 getPositionForSection(int section)79 public int getPositionForSection(int section) { 80 if (section < 0 || section >= mSections.length) { 81 return -1; 82 } 83 84 return mPositions[section]; 85 } 86 getSectionForPosition(int position)87 public int getSectionForPosition(int position) { 88 if (position < 0 || position >= mCount) { 89 return -1; 90 } 91 92 int index = Arrays.binarySearch(mPositions, position); 93 94 /* 95 * Consider this example: section positions are 0, 3, 5; the supplied 96 * position is 4. The section corresponding to position 4 starts at 97 * position 3, so the expected return value is 1. Binary search will not 98 * find 4 in the array and thus will return -insertPosition-1, i.e. -3. 99 * To get from that number to the expected value of 1 we need to negate 100 * and subtract 2. 101 */ 102 return index >= 0 ? index : -index - 2; 103 } 104 setFavoritesHeader(int numberOfItemsToAdd)105 public void setFavoritesHeader(int numberOfItemsToAdd) { 106 if (mSections != null) { 107 // Don't do anything if the header is already set properly. 108 if (mSections.length > 0 && mSections[0].isEmpty()) { 109 return; 110 } 111 112 // Since the section indexer isn't aware of the profile at the top, we need to add a 113 // special section at the top for it and shift everything else down. 114 String[] tempSections = new String[mSections.length + 1]; 115 int[] tempPositions = new int[mPositions.length + 1]; 116 // Favorites section is empty to hide fast scroll preview. 117 tempSections[0] = ""; 118 tempPositions[0] = 0; 119 for (int i = 1; i <= mPositions.length; i++) { 120 tempSections[i] = mSections[i - 1]; 121 tempPositions[i] = mPositions[i - 1] + numberOfItemsToAdd; 122 } 123 mSections = tempSections; 124 mPositions = tempPositions; 125 mCount = mCount + numberOfItemsToAdd; 126 } 127 } 128 } 129