插入仅从带有复选框的自定义列表中选择的类

Question

我正在使用这个带有复选框的自定义列表视图。

如何获取选中复选框的每一行的名称并将其添加到类中？

这是我的代码：

 SetContentView(Resource.Layout.ExtrasPreviewMain);
        OverridePendingTransition(Resource.Layout.trans_left_in, Resource.Layout.trans_left_out);
        var BackBtn = FindViewById<Button>(Resource.Id.ExtrasBackButton);
        var AcceptBtn = FindViewById<Button>(Resource.Id.ExtrasAcceptButton);
        AcceptBtn.Click += AcceptBtn_Click;



        con.Open();
        SqlCommand sqlCmd = new SqlCommand("SELECT Name from InventoryMaster where MainGroupItemID=" + Connection.CategoryID + "", con);

        mlistview = FindViewById<ListView>(Resource.Id.ExtrasList);
        mItems = new List<ExtrasPreviewClass>();
        SqlDataReader sqlReader = sqlCmd.ExecuteReader();
        while (sqlReader.Read())
        {
            mItems.Add(new ExtrasPreviewClass() { ExtrasName = sqlReader["Name"].ToString() });


        }
        MyListViewAdapterExtras adapter = new MyListViewAdapterExtras(this, mItems);
        mlistview.Adapter = adapter;
        sqlReader.Close();
        con.Close();
    }

    private void AcceptBtn_Click(object sender, EventArgs e)
    {
        var checkbox = FindViewById<CheckBox>(Resource.Id.txtExtrasCheckBox);
        var name = FindViewById<TextView>(Resource.Id.txtExtrasName);


           foreach (var item in mItems)
        {
            if (Convert.ToBoolean(item.ExtrasCheckBox)== true)
            {
                Connection.Extras = Connection.Extras + item.ExtrasName + ",";
            }
        }

但它在我的最后一个结果中没有显示任何内容 例如，如果会有

附加复选框 糖检查 牛奶检查

我的结果将为空

这是我的适配器代码：

  class MyListViewAdapterExtras : BaseAdapter<ExtrasPreviewClass>
{
    public List<ExtrasPreviewClass> mitems;
    private Context mContext;
    public MyListViewAdapterExtras(Context context, List<ExtrasPreviewClass> items)
    {
        mitems = items;
        mContext = context;

    }
    public override int Count
    {
        get
        {
            return mitems.Count;
        }
    }
    public override long GetItemId(int position)
    {
        return position;
    }
    public override ExtrasPreviewClass this[int position]
    {
        get
        {
            return mitems[position];
        }

    }
    public override View GetView(int position, View convertView, ViewGroup parent)
    {
        View row = convertView;
        if (row == null)
        {
            row = LayoutInflater.From(mContext).Inflate(Resource.Layout.ExtrasPreview, null, false);

        }



        TextView txtExtrasName = row.FindViewById<TextView>(Resource.Id.txtExtrasName);
        txtExtrasName.Text = mitems[position].ExtrasName;
        CheckBox txtExtrasCheckBox = row.FindViewById<CheckBox>(Resource.Id.txtExtrasCheckBox);
        txtExtrasCheckBox.Text = Convert.ToString(mitems[position].ExtrasCheckBox);



        return row;
    }

还有我的班级

class ExtrasPreviewClass
{
    public string ExtrasName { get; set; }
    public CheckBox ExtrasCheckBox { get; set; }
}

Answer 1

在 Adapter 的 GetView 方法中，您必须为 CheckBox 设置一个 Tag，包含项目信息，并为 CheckBox 的 CheckedChanged 注册一个 EventListener，如下所示：

public override View GetView(int position, View convertView, ViewGroup parent)
{
    //Prepare convertView here
    CheckBox itemCheckBox = convertView.FindViewById<CheckBox>(Resource.Id.itemCheckBox);
    if(itemCheckBox.Tag == null)
        itemCheckBox.Tag = new Java.Lang.String(this.items[position].name); //set the checkbox tag with information about your item. The tag object class must inherit from Java.Lang.Object
    itemCheckBox.CheckedChange -= itemCheckBox_CheckedChange; //this is to avoid registering the event more than once when scrolling the listview
    itemCheckBox.CheckedChange += itemCheckBox_CheckedChange;
    return convertView;
}

private void itemCheckBox_CheckedChange(object sender, EventArgs e)
{
    // CheckBox myCheckBox = (CheckBox)sender;
    // Java.Lang.Object myTag = myCheckBox.Tag;
    // String itemName = ((Java.Lang.String)myTag).ToString();
    //save in a variable that your item was checked
    //for example:
    // foreach(Item i in this.items)
    // {
    //     if(i.name.Equals(itemName))
    //     {
    //         i.IsChecked = myCheckBox.Checked;
    //         break;
    //     }
    // }
}