大家好，我叫谷口
我实现了一个recyclerview，并将recyclerview项划分为一组。当我尝试分为两组时，没有显示代码错误，但是出现在回收站上的所有项目仅显示了viewholder textview名称
如下图所示：
https://drive.google.com/open?id=1TX5R0o44v-nWcTduYsqmH7KCFSDraZ24
第一类清单：
public class DateNow : ListItem
{
public string dateNow{ set; get; }
public override int getType()
{
return TYPE_HEADER_NOW;
}
}
第一位观看者：
public class RecyclerViewNowHolder : RecyclerView.ViewHolder
{
public TextView mDateNow;
public RecyclerViewNowHolder(View itemView) : base(itemView)
{
mDateNow = itemView.FindViewById<TextView>(Resource.Id.mDateNow);
}
}
}
第二列表类别：
public class DateYesterday : ListItem
{
public string dateYesterday { set; get; }
public override int getType()
{
return TYPE_HEADER_YESTERDAY;
}
}
第二个观看者：
public class RecyclerViewYesterdayHolder : RecyclerView.ViewHolder
{
public TextView mDateYesterday;
public RecyclerViewYesterdayHolder(View itemView) : base(itemView)
{
mDateYesterday = itemView.FindViewById<TextView>(Resource.Id.mDateYesterday);
}
}
清单项目类别：
public abstract class ListItem
{
public static int TYPE_HEADER = 0;
public static int TYPE_CONTENT = 1;
public static int TYPE_HEADER_NOW = 2;
public static int TYPE_HEADER_YESTERDAY = 3;
abstract public int getType();
}
我的recyclerview适配器：
public class RecyclerAdapter : RecyclerView.Adapter
{
private Activity mActivity;
private List<ListItem> mEmails;
private Context context;
public RecyclerAdapter(List<ListItem> emails, Context context)
{
mEmails = emails;
this.context = context;
}
public RecyclerAdapter(List<ListItem> emails, Activity activity)
{
mEmails = emails;
mActivity = activity;
}
public class MyView : RecyclerView.ViewHolder
{
public View mMainView { get; set; }
public TextView mName { get; set; }
public TextView mSubject { get; set; }
public TextView mMessage { get; set; }
public MyView(View view) : base(view)
{
mMainView = view;
}
}
public override int ItemCount
{
get { return mEmails.Count; }
}
public override int GetItemViewType(int position)
{
return mEmails[position].getType();
}
public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
{
if (viewType == ListItem.TYPE_HEADER_NOW)
{
View headNow = LayoutInflater.From(parent.Context).Inflate(Resource.Layout.recyclerviewNow, parent, false);
RecyclerViewNowHolder view = new RecyclerViewNowHolder(headNow);
return view;
}
else if (viewType == ListItem.TYPE_HEADER_YESTERDAY)
{
View headYesterday = LayoutInflater.From(parent.Context).Inflate(Resource.Layout.recyclerviewYesterday, parent, false);
RecyclerViewYesterdayHolder view = new RecyclerViewYesterdayHolder(headYesterday);
return view;
}
else
{
View row = LayoutInflater.From(parent.Context).Inflate(Resource.Layout.row, parent, false);
RecyclerViewHolder view = new RecyclerViewHolder(row);
return view;
}
}
public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int position)
{
int type = GetItemViewType(position);
if (type == ListItem.TYPE_HEADER_NOW)
{
RecyclerViewNowHolder myHolder = holder as RecyclerViewNowHolder;
myHolder.mDateNow.Text = "Hoje";
}
else if (type == ListItem.TYPE_HEADER_YESTERDAY)
{
RecyclerViewYesterdayHolder myHolder = holder as RecyclerViewYesterdayHolder;
myHolder.mDateYesterday.Text = "Ontem";
}
else
{
RecyclerViewHolder myHolder = holder as RecyclerViewHolder;
myHolder.mDate.Text = ((Email)mEmails[position]).date;
myHolder.mSubject.Text = ((Email)mEmails[position]).Subject;
myHolder.mMessage.Text = ((Email)mEmails[position]).Message;
}
}
}
我的主要活动类别：
[Activity(Label = "@string/app_name", Theme = "@style/AppTheme", MainLauncher = true)]
public class MainActivity : AppCompatActivity
{
public static RecyclerView mRecyclerView;
public static RecyclerView.LayoutManager mLayoutManager;
public RecyclerView.ViewHolder holder;
public static BottomNavigationView bottomnavigationview1;
public static RecyclerView.Adapter mAdapter;
public static List<Email> mEmails;
private List<ListItem> mItems;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
Xamarin.Essentials.Platform.Init(this, bundle);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.activity_main);
mRecyclerView = FindViewById<RecyclerView>(Resource.Id.recyclerViwer);
mRecyclerView.AddItemDecoration(new DividerItemDecoration(mRecyclerView.Context, DividerItemDecoration.Vertical));
mRecyclerView.HasFixedSize = true;
SetupList();
//Create our layout Manager
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.SetLayoutManager(mLayoutManager);
RecyclerAdapter mAdapter = new RecyclerAdapter(mItems, this);
mRecyclerView.SetAdapter(mAdapter);
}
private void SetupList()
{
mEmails = new List<Email>();
mEmails.Add(new Email() { date = "9/24/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "9/23/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "9/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "9/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "9/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "8/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "8/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "7/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "7/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "6/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "6/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "5/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "5/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "4/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "4/19/2019", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "9/19/2018", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
mEmails.Add(new Email() { date = "9/19/2018", Subject = "Wanna Hang Out?", Message = "I ' ll be around tomorrow!!" });
List<string> dateList = new List<string>();
List<DateNow> dateItems = new List<DateNow>();
List<DateYesterday> dateYesterday = new List<DateYesterday>();
mItems = new List<ListItem>();
foreach (var email in mEmails)
{
if (!dateList.Contains(email.date))
{
dateList.Add(email.date);
dateItems.Add(new DateNow() { dateNow = email.date });
dateYesterday.Add(new DateYesterday() { dateYesterday = email.date });
}
}
DateTime today = DateTime.Today;
string sub = today.ToString().Substring(0, 9);
int yesterday = Convert.ToInt32(today.Day.ToString()) - 1;
foreach (var date in dateItems)
{
mItems.Add(date);
foreach (var email in mEmails)
{
if (date.dateNow.Equals(DateTime.Now.Day.ToString()))
{
mItems.Add(email);
}
}
}
}
从您的代码中，我们发现您仅遍历列表dateItems并将dateItems的子代添加到mItems，并且mItems是RecyclerView的数据源：
foreach (var date in dateItems)
{
mItems.Add(date);
foreach (var email in mEmails)
{
if (date.dateNow.Equals(DateTime.Now.Day.ToString()))
{
mItems.Add(email);
}
}
}
并且从下面的代码中，我们可以看到List<DateNow> dateItems = new List<DateNow>();，并且dateItems是DateNow类型的数据的集合。
List<string> dateList = new List<string>();
List<DateNow> dateItems = new List<DateNow>();
List<DateYesterday> dateYesterday = new List<DateYesterday>();
mItems = new List<ListItem>();
foreach (var email in mEmails)
{
if (!dateList.Contains(email.date))
{
dateList.Add(email.date);
dateItems.Add(new DateNow() { dateNow = email.date });
dateYesterday.Add(new DateYesterday() { dateYesterday = email.date });
}
}
因此，回收站仅显示RecyclerViewNowHolder文本视图名称（DateNow），其方法getType()为TYPE_HEADER_NOW。
注：
如果添加以下代码，您会发现回收站还将显示RecyclerViewYesterdayHolder ViewHolder。
foreach (var date in dateYesterday) {
mItems.Add(date);
}