字母索引定位，仿联系人列表功能，实现字母A-Z排序

package com.ss.wavesidebardemo.data; public class City { public static final String DATA = "[{\"id\":\"2\",\"name\":\"北京\"},{\"id\":\"5\",\"name\":\"天津\"},{\"id\":\"1\",\"name\":\"上海\"},{\"id\":\"6\",\"name\":\"重庆\"},{\"id\":\"138\",\"name\":\"安庆\"},{\"id\":\"122\",\"name\":\"蚌埠\"},{\"id\":\"266\",\"name\":\"亳州\"},{\"id\":\"243\",\"name\":\"池州\"},{\"id\":\"158\",\"name\":\"滁州\"},{\"id\":\"197\",\"name\":\"阜阳\"},{\"id\":\"31\",\"name\":\"合肥\"},{\"id\":\"222\",\"name\":\"淮北\"},{\"id\":\"165\",\"name\":\"淮南\"},{\"id\":\"82\",\"name\":\"黄山\"},{\"id\":\"195\",\"name\":\"六安\"},{\"id\":\"154\",\"name\":\"马鞍山\"},{\"id\":\"169\",\"name\":\"宿州\"},{\"id\":\"254\",\"name\":\"铜陵\"},{\"id\":\"112\",\"name\":\"芜湖\"},{\"id\":\"186\",\"name\":\"宣城\"},{\"id\":\"22\",\"name\":\"福州\"},{\"id\":\"145\",\"name\":\"龙岩\"},{\"id\":\"193\",\"name\":\"南平\"},{\"id\":\"141\",\"name\":\"宁德\"},{\"id\":\"168\",\"name\":\"莆田\"},{\"id\":\"60\",\"name\":\"泉州\"},{\"id\":\"134\",\"name\":\"三明\"},{\"id\":\"19\",\"name\":\"厦门\"},{\"id\":\"175\",\"name\":\"漳州\"},{\"id\":\"212\",\"name\":\"潮州\"},{\"id\":\"27\",\"name\":\"东莞\"},{\"id\":\"28\",\"name\":\"佛山\"},{\"id\":\"3\",\"name\":\"广州\"},{\"id\":\"182\",\"name\":\"河源\"},{\"id\":\"71\",\"name\":\"惠州\"},{\"id\":\"67\",\"name\":\"江门\"},{\"id\":\"199\",\"name\":\"揭阳\"},{\"id\":\"96\",\"name\":\"茂名\"},{\"id\":\"129\",\"name\":\"梅州\"},{\"id\":\"114\",\"name\":\"清远\"},{\"id\":\"55\",\"name\":\"汕头\"},{\"id\":\"239\",\"name\":\"汕尾\"},{\"id\":\"102\",\"name\":\"韶关\"},{\"id\":\"11\",\"name\":\"深圳\"},{\"id\":\"80\",\"name\":\"阳江\"},{\"id\":\"248\",\"name\":\"云浮\"},{\"id\":\"111\",\"name\":\"湛江\"},{\"id\":\"91\",\"name\":\"肇庆\"},{\"id\":\"61\",\"name\":\"中山\"},{\"id\":\"36\",\"name\":\"珠海\"},{\"id\":\"320\",\"name\":\"白银\"},{\"id\":\"345\",\"name\":\"定西\"},{\"id\":\"316\",\"name\":\"甘南\"},{\"id\":\"292\",\"name\":\"嘉峪关\"},{\"id\":\"346\",\"name\":\"金昌\"},{\"id\":\"218\",\"name\":\"酒泉\"},{\"id\":\"39\",\"name\":\"兰州\"},{\"id\":\"327\",\"name\":\"临夏\"},{\"id\":\"334\",\"name\":\"陇南\"},{\"id\":\"314\",\"name\":\"平凉\"},{\"id\":\"293\",\"name\":\"庆阳\"},{\"id\":\"272\",\"name\":\"天水\"},{\"id\":\"304\",\"name\":\"武威\"},{\"id\":\"270\",\"name\":\"张掖\"},{\"id\":\"262\",\"name\":\"百色\"},{\"id\":\"156\",\"name\":\"北海\"},{\"id\":\"318\",\"name\":\"崇左\"},{\"id\":\"282\",\"name\":\"防城港\"},{\"id\":\"244\",\"name\":\"贵港\"},{\"id\":\"52\",\"name\":\"桂林\"},{\"id\":\"280\",\"name\":\"河池\"},{\"id\":\"213\",\"name\":\"贺州\"},{\"id\":\"332\",\"name\":\"来宾\"},{\"id\":\"121\",\"name\":\"柳州\"},{\"id\":\"37\",\"name\":\"南宁\"},{\"id\":\"268\",\"name\":\"钦州\"},{\"id\":\"178\",\"name\":\"梧州\"},{\"id\":\"245\",\"name\":\"玉林\"},{\"id\":\"256\",\"name\":\"安顺\"},{\"id\":\"343\",\"name\":\"毕节\"},{\"id\":\"34\",\"name\":\"贵阳\"},{\"id\":\"286\",\"name\":\"六盘水\"},{\"id\":\"228\",\"name\":\"黔东南\"},{\"id\":\"303\",\"name\":\"黔南\"},{\"id\":\"301\",\"name\":\"黔西南\"},{\"id\":\"308\",\"name\":\"铜仁\"},{\"id\":\"187\",\"name\":\"遵义\"},{\"id\":\"58\",\"name\":\"保定\"},{\"id\":\"104\",\"name\":\"沧州\"},{\"id\":\"128\",\"name\":\"承德\"},{\"id\":\"233\",\"name\":\"恩施\"},{\"id\":\"310\",\"name\":\"鄂州\"},{\"id\":\"72\",\"name\":\"邯郸\"},{\"id\":\"207\",\"name\":\"衡水\"},{\"id\":\"153\",\"name\":\"黄冈\"},{\"id\":\"173\",\"name\":\"黄石\"},{\"id\":\"124\",\"name\":\"荆州\"},{\"id\":\"220\",\"name\":\"荆门\"},{\"id\":\"66\",\"name\":\"廊坊\"},{\"id\":\"302\",\"name\":\"潜江\"},{\"id\":\"57\",\"name\":\"秦皇岛\"},{\"id\":\"353\",\"name\":\"神农架林区\"},{\"id\":\"26\",\"name\":\"石家庄\"},{\"id\":\"170\",\"name\":\"十堰\"},{\"id\":\"260\",\"name\":\"随州\"},{\"id\":\"74\",\"name\":\"唐山\"},{\"id\":\"337\",\"name\":\"天门\"},{\"id\":\"4\",\"name\":\"武汉\"},{\"id\":\"150\",\"name\":\"襄阳\"},{\"id\":\"250\",\"name\":\"咸宁\"},{\"id\":\"342\",\"name\":\"仙桃\"},{\"id\":\"236\",\"name\":\"孝感\"},{\"id\":\"70\",\"name\":\"邢台\"},{\"id\":\"94\",\"name\":\"宜昌\"},{\"id\":\"137\",\"name\":\"张家口\"},{\"id\":\"97\",\"name\":\"大庆\"},{\"id\":\"297\",\"name\":\"大兴安岭\"},{\"id\":\"23\",\"name\":\"哈尔滨\"},{\"id\":\"324\",\"name\":\"鹤岗\"},{\"id\":\"230\",\"name\":\"黑河\"},{\"id\":\"200\",\"name\":\"佳木斯\"},{\"id\":\"216\",\"name\":\"鸡西\"},{\"id\":\"139\",\"name\":\"牡丹江\"},{\"id\":\"148\",\"name\":\"齐齐哈尔\"},{\"id\":\"326\",\"name\":\"七台河\"},{\"id\":\"330\",\"name\":\"双鸭山\"},{\"id\":\"311\",\"name\":\"绥化\"},{\"id\":\"306\",\"name\":\"伊春\"},{\"id\":\"147\",\"name\":\"安阳\"},{\"id\":\"367\",\"name\":\"白沙\"},{\"id\":\"335\",\"name\":\"保亭\"},{\"id\":\"190\",\"name\":\"常德\"},{\"id\":\"355\",\"name\":\"昌江\"},{\"id\":\"29\",\"name\":\"长沙\"},{\"id\":\"340\",\"name\":\"澄迈县\"},{\"id\":\"214\",\"name\":\"郴州\"},{\"id\":\"281\",\"name\":\"儋州\"},{\"id\":\"349\",\"name\":\"定安县\"},{\"id\":\"328\",\"name\":\"东方\"},{\"id\":\"42\",\"name\":\"海口\"},{\"id\":\"291\",\"name\":\"鹤壁\"},{\"id\":\"142\",\"name\":\"衡阳\"},{\"id\":\"247\",\"name\":\"怀化\"},{\"id\":\"149\",\"name\":\"焦作\"},{\"id\":\"325\",\"name\":\"济源\"},{\"id\":\"118\",\"name\":\"开封\"},{\"id\":\"357\",\"name\":\"乐东\"},{\"id\":\"362\",\"name\":\"临高县\"},{\"id\":\"333\",\"name\":\"陵水\"},{\"id\":\"279\",\"name\":\"娄底\"},{\"id\":\"264\",\"name\":\"漯河\"},{\"id\":\"59\",\"name\":\"洛阳\"},{\"id\":\"115\",\"name\":\"南阳\"},{\"id\":\"179\",\"name\":\"平顶山\"},{\"id\":\"219\",\"name\":\"濮阳\"},{\"id\":\"261\",\"name\":\"琼海\"},{\"id\":\"361\",\"name\":\"琼中\"},{\"id\":\"237\",\"name\":\"三门峡\"},{\"id\":\"370\",\"name\":\"三沙\"},{\"id\":\"51\",\"name\":\"三亚\"},{\"id\":\"204\",\"name\":\"商丘\"},{\"id\":\"215\",\"name\":\"邵阳\"},{\"id\":\"363\",\"name\":\"屯昌县\"},{\"id\":\"288\",\"name\":\"万宁\"},{\"id\":\"300\",\"name\":\"文昌\"},{\"id\":\"344\",\"name\":\"五指山\"},{\"id\":\"174\",\"name\":\"湘潭\"},{\"id\":\"127\",\"name\":\"湘西\"},{\"id\":\"79\",\"name\":\"新乡\"},{\"id\":\"161\",\"name\":\"信阳\"},{\"id\":\"116\",\"name\":\"许昌\"},{\"id\":\"224\",\"name\":\"益阳\"},{\"id\":\"276\",\"name\":\"永州\"},{\"id\":\"183\",\"name\":\"岳阳\"},{\"id\":\"108\",\"name\":\"张家界\"},{\"id\":\"21\",\"name\":\"郑州\"},{\"id\":\"226\",\"name\":\"周口\"},{\"id\":\"235\",\"name\":\"驻马店\"},{\"id\":\"143\",\"name\":\"株洲\"},{\"id\":\"176\",\"name\":\"白城\"},{\"id\":\"274\",\"name\":\"白山\"},{\"id\":\"13\",\"name\":\"长春\"},{\"id\":\"90\",\"name\":\"吉林\"},{\"id\":\"287\",\"name\":\"辽源\"},{\"id\":\"241\",\"name\":\"四平\"},{\"id\":\"238\",\"name\":\"松原\"},{\"id\":\"227\",\"name\":\"通化\"},{\"id\":\"196\",\"name\":\"延边\"},{\"id\":\"35\",\"name\":\"常州\"},{\"id\":\"93\",\"name\":\"淮安\"},{\"id\":\"75\",\"name\":\"连云港\"},{\"id\":\"7\",\"name\":\"南京\"},{\"id\":\"41\",\"name\":\"南通\"},{\"id\":\"223\",\"name\":\"宿迁\"},{\"id\":\"14\",\"name\":\"苏州\"},{\"id\":\"92\",\"name\":\"泰州\"},{\"id\":\"17\",\"name\":\"无锡\"},{\"id\":\"54\",\"name\":\"徐州\"},{\"id\":\"95\",\"name\":\"盐城\"},{\"id\":\"38\",\"name\":\"扬州\"},{\"id\":\"53\",\"name\":\"镇江\"},{\"id\":\"252\",\"name\":\"抚州\"},{\"id\":\"78\",\"name\":\"赣州\"},{\"id\":\"151\",\"name\":\"吉安\"},{\"id\":\"225\",\"name\":\"景德镇\"},{\"id\":\"103\",\"name\":\"九江\"},{\"id\":\"33\",\"name\":\"南昌\"},{\"id\":\"263\",\"name\":\"萍乡\"},{\"id\":\"123\",\"name\":\"上饶\"},{\"id\":\"257\",\"name\":\"新余\"},{\"id\":\"132\",\"name\":\"宜春\"},{\"id\":\"284\",\"name\":\"鹰潭\"},{\"id\":\"88\",\"name\":\"�