这两天看了个Demo，自己也动手写了下，觉得效果还不错，分享一下！
主要是利用ListActivity中自带了一个ListView和ListAdapter来实现的，当然也可以在一般的Activity中添加ListView和ListAdapter来实现。具体代码如下：
显示自定义的适配器的实现：
//HomeScreenAdapter.cs using System; using System.Collections.Generic; using System.Linq; using System.Text; using Android.App; using Android.Content; using Android.OS; using Android.Runtime; using Android.Views; using Android.Widget; namespace ListViewAdapter { [Activity(Label = "ListViewAdapter")] public class HomeScreenAdapter : BaseAdapter<string> { private string[] items; private Activity context; public HomeScreenAdapter(Activity context, string[] items) : base() { this.context = context; this.items = items; } public override string this[int position] { get { return items[position]; } } public override int Count { get { return items.Length; } } public override long GetItemId(int position) { return position; } public override View GetView(int position, View convertView, ViewGroup parent) { View view = convertView; if (view == null) { view = context.LayoutInflater.Inflate(Android.Resource.Layout.SimpleListItem1, null); } view.FindViewById<TextView>(Android.Resource.Id.Text1).Text = items[position]; return view; } } }
自定义适配器实现之后，只要将它赋给ListActivity中ListAdapter成员就可以了。
下面看看主类HomeScreen.cs的实现：
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
namespace SectionIndex
{
[Activity(Label = "SectionIndex", MainLauncher = true, Icon = "@drawable/icon")]
public class HomeScreen : ListActivity
{
private string[] items;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
//用于存放文本文件的List
List<string> veges = new List<string>();
//利用流来打开文本文件
Stream seedDataStream = Assets.Open(@"VegeData.txt");
//将文本文件内容读入veges中
//StringBuilder sb = new StringBuilder();
using (StreamReader reader = new StreamReader(seedDataStream))
{
while (!reader.EndOfStream)
{
veges.Add(reader.ReadLine());
}
}
//将veges中的元素进行排序,比较器为匿名函数构成的委托
veges.Sort((x,y)=>{ return x.CompareTo(y); } );
//将列表中的元素存入数组中
items = veges.ToArray();
}
protected override void OnListItemClick(ListView l, View v, int position, long id)
{
var t = items[position];
Toast.MakeText(this, t, ToastLength.Short).Show();
Console.WriteLine("Clicked on: " + t);
}
}
}
其中VegesData.txt为要读取的文本文件：其内容如下：
Beet greens Bitterleaf Bok choy Broccoli Rabe Brussels sprout Cabbage Catsear Celery Celtuce Ceylon spinach Chard Chaya Chickweed Chicory Chinese cabbage Chinese Mallow Chrysanthemum leaves Collard greens Corn salad Cress Dandelion Endive Epazote Fat hen Fiddlehead Fluted pumpkin Garden Rocket Golden samphire Good King Henry Greater Plantain Kai-lan Kale Komatsuna Kuka Lagos bologi Lamb's lettuce Land cress Lettuce Lizard's tail Melokhia Mizuna greens Mustard Napa cabbage New Zealand Spinach Orache Pak choy Paracress Pea sprouts/leaves Poke Radicchio Samphire Sea beet Sea kale Sierra Leone bologi Soko Sorrel Spinach Summer purslane Swiss chard Tatsoi Turnip greens Watercress Water spinach Winter purslane Yarrow Avocado Bell pepper Bitter melon/Bitter gourd Courgette Cucumber Ivy Gourd Eggplant/Aubergine/Brinjal Pumpkin Squash Sweet corn aka corn; aka maize Sweet pepper Tinda Tomatillo Tomato Winter melon West Indian gherkin Zucchini Artichoke Broccoli Cauliflower Courgette flowers Squash blossoms American groundnut Azuki bean Black-eyed pea Chickpea Common bean Drumstick Dolichos bean Fava bean Garbanzo Green bean Guar Gumbo Horse gram Indian pea Lentil Lima Bean Moth bean Mung bean Okra Pea Peanut Pigeon pea Ricebean Runner bean Snap pea Snow pea Soybean Tarwi Tepary bean Urad bean Velvet bean Winged bean Yardlong bean Asparagus Cardoon Celeriac Celery Elephant Garlic Florence fennel Garlic Kohlrabi Kurrat Leek Lotus root Nopal Onion Spring Onion/Scallion Prussian asparagus Shallot Welsh onion Wild leek Ahipa Arracacha Bamboo shoot Beetroot Burdock Broadleaf arrowhead Camas Canna Carrot Cassava Chinese artichoke Daikon Earthnut pea Elephant Foot yam Ensete Ginger Gobo Hamburg parsley Jerusalem artichoke Jícama Manioc Mooli Parsnip Pignut Plectranthus Potato Prairie turnip Radish Horseradish Rutabaga Salsify Scorzonera Skirret Swede Sweet Potato or Kumara Taro Ti Tigernut Turnip Ulluco Water chestnut Yacón Yam
关键部分就是如何实现ISectionIndexer这个接口。