如何在 Mono for Android 上制作 ExpandableListView

Question

我正在尝试制作一个可扩展的 ListView，但我不知道如何从 ExpandableListAdapter 检索某些方法的信息，所以这是我的代码： 这是主要活动：

[Activity (Label = "AR Transactions Details")]          
public class ARInquiry : ExpandableListActivity
{
    private ARExpandableListAdapter adapter;
    private string[] groups = {"1","2","3","4"};
    private string[,] children = {
            { "Arnold", "Barry", "Chuck", "David" },
            {"Ace", "Bandit", "Cha-Cha", "Deuce"},
            { "Fluffy", "Snuggles", "", ""},
            { "Goldy", "Bubbles", "", "" }
    };

    protected override void OnCreate (Bundle bundle)
    {
        base.OnCreate (bundle);
        SetContentView(Resource.Layout.ar_inquiry);

        //Restrieve the ExpandableListView from the layout
        ExpandableListView listview = FindViewById<ExpandableListView>(Android.Resource.Id.List);

        //Initialize the adapter with blank groups and children
        //We will be adding children on a thread, and then update the ListView
        adapter = new ARExpandableListAdapter(this, groups, children);

        listview.SetAdapter(adapter);
    }
}

这是 ExpandableListViewAdapter 类代码：

public class ARExpandableListAdapter : BaseExpandableListAdapter
{
    private Context context;
    private string[] groups;
    private string[,] children;

    public ARExpandableListAdapter(Context context, string[] groups, string[,] children)
    {
        this.context = context;
        this.groups = groups;
        this.children = children;
    } 


    public override Java.Lang.Object GetChild (int groupPosition, int childPosition)
    {
        return children[groupPosition, childPosition];
    }

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

    public override View GetChildView (int groupPosition, int childPosition, bool isLastChild, View convertView, ViewGroup parent)
    {
        if(convertView == null)
        {
            LayoutInflater infaInflater = (LayoutInflater) context.GetSystemService(Context.LayoutInflaterService);
            convertView = infaInflater.Inflate(Resource.Layout.child_layout, null);
        }

        TextView tv = (TextView) convertView.FindViewById(Resource.Id.tvChild);
        if(isLastChild == true)
        {
          return convertView;   
        }
        tv.SetText(" " + children[groupPosition, childPosition], TextView.BufferType.Normal);

        return convertView;
    }

    public override int GetChildrenCount (int groupPosition)
    {
        return children[groupPosition, 3];
    }

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

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

    public override View GetGroupView (int groupPosition, bool isExpanded, View convertView, ViewGroup parent)
    {
        string _group = (string)GetGroup(groupPosition);
        if(convertView==null)
        {
            LayoutInflater infalInflater = (LayoutInflater) context.GetSystemService(Context.LayoutInflaterService);
            convertView = infalInflater.Inflate(Resource.Layout.group_layout, null);
        }
        TextView tv = (TextView)convertView.FindViewById(Resource.Id.tvGroup);
        tv.SetText(_group, TextView.BufferType.Normal);
        return convertView;
    }

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

    public override int GroupCount {
        get {
            return groups.Count();
        }
    }

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


}

如何获取 GetChildrenCount 方法的长度？

Answer 1

要获得子组的长度，它应该是：

public override int GetChildrenCount (int groupPosition)
{
    return children[groupPosition].Length;
}

Answer 2

我这样解决，因为它的工作原理：

public class ARExpandableListAdapter : BaseExpandableListAdapter
{

    private Context context;
    private IList<string> groups;
    private IList<IAccountsReceivable> children;

    public ARExpandableListAdapter(Context context, IList<string> groups, IList<IAccountsReceivable> children)
    {
        this.context = context;
        this.groups = groups;
        this.children = children;
    } 

    #region implemented abstract members of Android.Widget.BaseExpandableListAdapter
    public override Java.Lang.Object GetChild (int groupPosition, int childPosition)
    {

        return (Java.Lang.Object)children[groupPosition]; //as Java.Lang.Object.JavaCast<decimal>();
    }

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

    public override View GetChildView (int groupPosition, int childPosition, bool isLastChild, View convertView, ViewGroup parent)
    {
        if(convertView == null)
        {
            LayoutInflater infaInflater = (LayoutInflater) context.GetSystemService(Context.LayoutInflaterService);
            convertView = infaInflater.Inflate(Resource.Layout.child_layout, null);
        }

        if(childPosition<6)
        {
            string label = " ";
            if (childPosition == 0)
                label = children[groupPosition].TransactionType;
            if (childPosition == 1)
                label = children[groupPosition].TransactionValue.ToString();
            if (childPosition == 2)
                label = children[groupPosition].TransactionDate.ToString();
            if (childPosition == 3)
                label = children[groupPosition].TransactionDueDate.ToString();
            if (childPosition == 4)
                label = children[groupPosition].OrderNumber.ToString();
            if (childPosition == 5)
                label = children[groupPosition].CustomerReference;


        TextView tv = (TextView) convertView.FindViewById(Resource.Id.tvChild);
        tv.SetText(" " + label, TextView.BufferType.Normal);
        }
        return convertView;
    }

    public override int GetChildrenCount (int groupPosition)
    {
        return children.Count;
    }

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

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

    public override View GetGroupView (int groupPosition, bool isExpanded, View convertView, ViewGroup parent)
    {
        string _group = (string)GetGroup(groupPosition);
        if(convertView==null)
        {
            LayoutInflater infalInflater = (LayoutInflater) context.GetSystemService(Context.LayoutInflaterService);
            convertView = infalInflater.Inflate(Resource.Layout.group_layout, null);
        }
        TextView tv = (TextView)convertView.FindViewById(Resource.Id.tvGroup);
        tv.SetText(_group, TextView.BufferType.Normal);
        return convertView;
    }

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

    public override int GroupCount {
        get {
            return groups.Count();
        }
    }

    public override bool HasStableIds {
        get {
            return true;
        }
    }
    #endregion

}