具有自定义对象的可过滤适配器

我想将自动完成文本框添加到 xamarin.android 中的列表视图（自定义对象）中。

我有一个列表视图，它是从字符串数组填充的。我想使用自定义对象填充我的列表视图。

下面的代码适用于字符串数组。任何帮助实现我的自定义对象适配器都会有所帮助。

这是代码：

主.axml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <EditText
        android:id="@+id/search"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text=""
        android:hint="Enter search query" />
    <Button
        android:id="@+id/dosearch"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Filter list" />
    <ListView
        android:id="@+id/list"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />
</LinearLayout>

主要活动

public class MainActivity : Activity
    {
        Button _button;
        ListView _listview;
        EditText _filterText;
        FilterableAdapter _adapter;

        protected override void OnCreate (Bundle bundle)
        {
            base.OnCreate (bundle);

            // Set our view from the "main" layout resource
            SetContentView (Resource.Layout.Main);

            _button = FindViewById<Button> (Resource.Id.dosearch);
            _listview = FindViewById<ListView> (Resource.Id.list);
            _filterText = FindViewById<EditText> (Resource.Id.search);
            _adapter = new FilterableAdapter (this, Android.Resource.Layout.SimpleListItem1, GetItems());
            _listview.Adapter = _adapter;

            _button.Click += delegate {
                // filter the adapter here
                _adapter.Filter.InvokeFilter(_filterText.Text);
            };

            _filterText.TextChanged += (object sender, Android.Text.TextChangedEventArgs e) => {
                // filter on text changed
                var searchTerm = _filterText.Text;
                if (String.IsNullOrEmpty(searchTerm)) {
                    _adapter.ResetSearch();
                } else {
                    _adapter.Filter.InvokeFilter(searchTerm);
                }
            };
        }

        string[] GetItems ()
        {
           string[] names = new string[] { "abc", "xyz", "yyy", "aaa" };
           return names;
        }
    }

    public class FilterableAdapter : ArrayAdapter, IFilterable
    {
        LayoutInflater inflater;
        Filter filter;
        Activity context;
        public string[] AllItems;
        public string[] MatchItems;

        public FilterableAdapter (Activity context, int txtViewResourceId, string[] items) : base(context, txtViewResourceId, items)
        {
            inflater = context.LayoutInflater;
            filter = new SuggestionsFilter(this);
            AllItems = items;
            MatchItems = items;
        }

        public override int Count {
            get {
                return MatchItems.Length;
            }
        }

        public override Java.Lang.Object GetItem (int position)
        {
            return MatchItems[position];
        }

        public override View GetView (int position, View convertView, ViewGroup parent)
        {
            View view = convertView;
            if (view == null)
                view = inflater.Inflate(Android.Resource.Layout.SimpleDropDownItem1Line, null);

            view.FindViewById<TextView>(Android.Resource.Id.Text1).Text = MatchItems[position];

            return view;
        }

        public override Filter Filter {
            get {
                return filter;
            }
        }

        public void ResetSearch() {
            MatchItems = AllItems;
            NotifyDataSetChanged ();
        }

        class SuggestionsFilter : Filter
        {
            readonly FilterableAdapter _adapter;

            public SuggestionsFilter (FilterableAdapter adapter) : base() {
                _adapter = adapter;
            }

            protected override Filter.FilterResults PerformFiltering (Java.Lang.ICharSequence constraint)
            {
                FilterResults results = new FilterResults();
                if (!String.IsNullOrEmpty (constraint.ToString ())) {
                    var searchFor = constraint.ToString ();
                    Console.WriteLine ("searchFor:" + searchFor);
                    var matchList = new List<string> ();

                    var matches = 
                        from i in _adapter.AllItems
                        where i.IndexOf (searchFor, StringComparison.InvariantCultureIgnoreCase) >= 0
                        select i;

                    foreach (var match in matches) {
                        matchList.Add (match);
                    }

                    _adapter.MatchItems = matchList.ToArray ();
                    Console.WriteLine ("resultCount:" + matchList.Count);

                    Java.Lang.Object[] matchObjects;
                    matchObjects = new Java.Lang.Object[matchList.Count];
                    for (int i = 0; i < matchList.Count; i++) {
                        matchObjects [i] = new Java.Lang.String (matchList [i]);
                    }

                    results.Values = matchObjects;
                    results.Count = matchList.Count;
                } else {
                    _adapter.ResetSearch ();
                }
                return results;
            }

            protected override void PublishResults (Java.Lang.ICharSequence constraint, Filter.FilterResults results)
            {
                _adapter.NotifyDataSetChanged();
            }
        }
    }

我想要这样的 getItem 方法：

 public List<ListObject> GetItems()
 {
     List<ListObject> model = new List<ListObject>();
     model.Add(new ListObject { id = 1, Name = "abc" });
     model.Add(new ListObject { id = 1, Name = "bcd" });
     model.Add(new ListObject { id = 1, Name = "def" });
     model.Add(new ListObject { id = 1, Name = "fgh" });
     return model;
 }

这样做的主要原因是我希望根据 edittext 中输入的数据来过滤我的列表。然后取出选择的Id并进行剩余的计算。

具有自定义对象的可过滤适配器

我写一个demo https://github.com/aixiaozi/Xamarin.Android.Views/tree/master/RecyclerViewSearch关于如何搜索RecyclerView，在我的演示中我填充了我的RecyclerView with List<Chemical>。更详细的信息，你可以阅读我的回答：通过 RecyclerView 搜索 https://stackoverflow.com/questions/44998483/searching-through-recyclerview-xamarin-droid/45011379#45011379

My Chemical class :

public class Chemical
{
    public string Name { get; set; }
    public int DrawableId { get; set; }
}

当填充RecyclerView :

var chemicals = new List<Chemical>
{
    new Chemical {Name = "Manganosulfate", DrawableId = Resource.Drawable.Icon},
    new Chemical {Name = "Natriummolybdate", DrawableId = Resource.Drawable.Icon},
    new Chemical {Name = "Ergocalciferol", DrawableId = Resource.Drawable.Icon},
    new Chemical {Name = "Cyanocobalamin", DrawableId = Resource.Drawable.Icon},
};

_adapter = new RecyclerViewAdapter(this,chemicals);

EDIT :

既然你正在使用ListView，你可以参考Cheesebaron 的 SearchView-示例 https://github.com/Cheesebaron/SearchView-Sample，我想这就是你想要的。

不要忘记添加对象扩展 https://github.com/Cheesebaron/SearchView-Sample/blob/master/SearchViewSample/ObjectExtensions.cs你的项目中的类。