Question

我正在尝试在扩展另一个群组后折叠之前的扩展群组。这里有很多教程，但对于java而言没有c＃。有人可以告诉我如何在C＃上实现，特别是Xamarin？我的ExpandableListViewAdapter：

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;
using Java.Lang;
using static Android.Widget.ExpandableListView;
using Java.Util.Zip;

namespace BarStar
{
public class ExpandableListViewAdapter : BaseExpandableListAdapter, IFilterable
{
    private Context context;
    public List<string> listGroup;
    public Dictionary<string, List<string>> listChild;
    private GroupFilter _filter;
    private int previousItem;
    private ExpandableListView _list;



    public ExpandableListViewAdapter(Context context, List<string> listGroup, Dictionary<string, List<string>> listChild)
    {
        this.context = context;
        this.listGroup = listGroup;
        this.listChild = listChild;
        _filter = new GroupFilter(this);

}
    public ExpandableListViewAdapter(Context context, List<string> listGroup, Dictionary<string, List<string>> listChild, ExpandableListView list) : this(context, listGroup, listChild)
    {

        _list = list; 
    }
    public override int GroupCount
    {
        get
        {
            return listGroup.Count;
        }
    }

    public override bool HasStableIds
    {
        get
        {
            return false;
        }
    }

    public Filter Filter => _filter;

    public override Java.Lang.Object GetChild(int groupPosition, int childPosition)
    {
        var result = new List<string>();
        listChild.TryGetValue(listGroup[groupPosition], out result);
        return result[childPosition];
    }

    public override long GetChildId(int groupPosition, int childPosition)
    {
        return childPosition;
    }

    public override int GetChildrenCount(int groupPosition)
    {
        var result = new List<string>();
        listChild.TryGetValue(listGroup[groupPosition], out result);
        return result.Count;
    }

    public override void OnGroupCollapsed(int groupPosition)
    {
        base.OnGroupCollapsed(groupPosition);
    }

    public override void OnGroupExpanded(int groupPosition)
    {
        if (groupPosition != previousItem)
        {
            _list.CollapseGroup(previousItem);

        }
        previousItem = groupPosition;
    }

    public override View GetChildView(int groupPosition, int childPosition, bool isLastChild, View convertView, ViewGroup parent)
    {
        {
            if (convertView == null)
            {
                LayoutInflater inflater = (LayoutInflater)context.GetSystemService(Context.LayoutInflaterService);
                convertView = inflater.Inflate(Resource.Layout.Children, null);
            }
            if (isLastChild == true)
            {
                EditText Submit = convertView.FindViewById<EditText>(Resource.Id.Submit);
                Button button = convertView.FindViewById<Button>(Resource.Id.Button);
                Submit.Visibility = ViewStates.Visible;
                button.Visibility = ViewStates.Visible;

                TextView textViewItem = convertView.FindViewById<TextView>(Resource.Id.DataValue);
                textViewItem.Visibility = ViewStates.Gone;
            }
            else
            {
                TextView textViewItem = convertView.FindViewById<TextView>(Resource.Id.DataValue);
                EditText Submit = convertView.FindViewById<EditText>(Resource.Id.Submit);
                Button button = convertView.FindViewById<Button>(Resource.Id.Button);
                button.Visibility = ViewStates.Gone;
                Submit.Visibility = ViewStates.Gone;
                textViewItem.Visibility = ViewStates.Visible;
                string content = (string)GetChild(groupPosition, childPosition);
                textViewItem.Text = content;
            }
            return convertView;
        }
    }

    public override Java.Lang.Object GetGroup(int groupPosition)
    {
        return listGroup[groupPosition];
    }

    public override long GetGroupId(int groupPosition)
    {
        return groupPosition;
    }

    public override View GetGroupView(int groupPosition, bool isExpanded, View convertView, ViewGroup parent)
    {
        if (convertView == null)
        {
            LayoutInflater inflater = (LayoutInflater)context.GetSystemService(Context.LayoutInflaterService);
            convertView = inflater.Inflate(Resource.Layout.Groups, null);
        }
        string textGroup = (string)GetGroup(groupPosition);
        TextView textViewGroup = convertView.FindViewById<TextView>(Resource.Id.Header);
        textViewGroup.Text = textGroup;
        return convertView;
    }

    public override bool IsChildSelectable(int groupPosition, int childPosition)
    {
        return true;
    }

    public bool onGroupClick(ExpandableListView parent, View v, int groupPosition,
    long id)
    {
        parent.SmoothScrollToPosition(groupPosition);

        if (parent.IsGroupExpanded(groupPosition))
        {
            parent.CollapseGroup(groupPosition);
        }
        else
        {
            parent.ExpandGroup(groupPosition);
        }

        return true;
    }


}

}

我刚编辑了这个并添加了适配器。一切都很好，但崩溃的部分。

编辑：

这是我的主要：

using Android.App;
using Android.Widget;
using Android.OS;
using System.Net;
using Java.Lang;
using System;
using Newtonsoft.Json.Linq;
using System.Linq;
using Java.Util;
using System.Threading;
using Org.Json;
using Android.Content;
using Android.Views;
using System.Collections.Generic;
using System.Text;
using RestSharp.Extensions.MonoHttp;
using Android.Text;
using Android.Views.InputMethods;
using Android.Util;

namespace BarStar
{
[Activity(Label = "BarStar", MainLauncher = true, Icon = "@drawable/logo")]
public class MainActivity : Activity
{
    private ExpandableListView list;
    private ExpandableListViewAdapter mAdapter;
    private int length;
    private List<string> group = new List<string>();
    private string[] names;
    private Dictionary<string, List<string>> Mapout = new Dictionary<string, List<string>>();
    private SearchView searchBar;
    private int length2;
    private EditText Submit;
    public string nameholder;
    private Button profileButton;

    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);
        SetContentView(Resource.Layout.Main);
        ActionBar.Hide();
        // Set Views
        searchBar = FindViewById<SearchView>(Resource.Id.searchBar);
        list = FindViewById<ExpandableListView>(Resource.Id.lv);
        Submit = FindViewById<EditText>(Resource.Id.Submit);
        var profileButton = FindViewById<Button>(Resource.Id.profileButton);
        profileButton.Click += ProfileButton_Click;

        //Set Groups
        WebClient client = new WebClient();
        string json = client.DownloadString("https://******");
        JSONArray myarray = new JSONArray(json);
        length = myarray.Length();
        names = new string[length];
        for (int i = 0; i < length; i++)
        {
            JSONObject Element = myarray.GetJSONObject(i);
            names[i] = Element.GetString("name");
        }
        setData(out mAdapter);
        list.SetAdapter(mAdapter);

        searchBar.QueryTextChange += searchBar_QueryTextChange;

    }

    private void ProfileButton_Click(object sender, EventArgs e)
    {
        Console.WriteLine("Works");
        StartActivity(typeof(ProfileActivity));
    }


private void searchBar_QueryTextChange(object sender, SearchView.QueryTextChangeEventArgs e)
    {

        mAdapter.Filter.InvokeFilter(e.NewText);
    }

    private void setData(out ExpandableListViewAdapter mAdapter)
    {
        string urlholder;
        string url;
        string json;
        string time;
        string timestamp;
        string together;
        WebClient client1 = new WebClient();
        for (int i = 0; i < length; i++)
        {
            List<string> listplaceholder = new List<string>();
            group.Add(names[i]);
            urlholder = Uri.EscapeDataString(names[i]);
            url = "*********" + urlholder + ".json";
            json = client1.DownloadString(url);
            JSONArray array2 = new JSONArray(json);
            length2 = array2.Length();
            for (int j = 0; j < length2; j++)
            {


                JSONObject Element = array2.GetJSONObject(j);
                time = Element.GetString("wait");
                JSONObject TimeElement = array2.GetJSONObject(j);
                timestamp = TimeElement.GetString("created_at");
                timestamp = timestamp.Replace("T", " at ");
                int index = timestamp.IndexOf(".");
                if (index > 0)
                {
                    timestamp = timestamp.Substring(0, index);
                }
                together = time + " minutes posted at " + timestamp;
                listplaceholder.Add(together);

            }
            Mapout.Add(group[i], listplaceholder);


        }
        mAdapter = new ExpandableListViewAdapter(this, group, Mapout,list);
    }
    }

Answer 1

有人可以告诉我如何在C＃上实施，特别是Xamarin吗？

您需要覆盖适配器的OutputClaim并折叠最后打开的组，修改适配器的构造函数以接受它的ExpandableListView，并为最后打开的组创建索引：

SelfAssertedAttributeProvider

以下是经过修改的演示：ExpandableListViewDemo。

在C＃中折叠组

1 个答案: