问题
so I had my RecyclerView In fragment tab, as usual using LinearLayoutManager
and I also want to use for Endless scroll ScrollListener,the problem is if I make a variable LinearLayoutManager in OnCreate method as below
public override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
mLayoutManager = new LinearLayoutManager(Context);
}
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View row = inflater.Inflate(Resource.Layout.Fragment3, container, false);
RecyclerView mRecyclerView = row.FindViewById<RecyclerView>(Resource.Id.recyclerView);
mRecyclerView.SetLayoutManager(mLayoutManager);
var scrollListener = new scroll(mLayoutManager);
mRecyclerView.AddOnScrollListener(scrollListener);
mRecyclerView.SetAdapter(mAdapter);
}
scrip at the top running properly but if I shift the tab or moving fragment will appear error, but I find a solution is
replace mRecyclerView.SetLayoutManager(mLayoutManager);
to : mRecyclerView.SetLayoutManager(new LinearLayoutManager(Context));
but endless scroll does not run, my question is
LinearLayout which one I should use in
var scrollListener = new scroll(mLayoutManager);
because it does not work...??
My full fragment code : `
downloadProcess.DoWork += DownloadProcess_DoWork;
downloadProcess.RunWorkerCompleted += DownloadProcess_RunWorkerCompleted;
downloadProcess.RunWorkerAsync();
mRootItem = new List<RowItems>();
mAdapter = new RecyclerAdapter(mRootItem, Context, mRecyclerView);
}
private void DownloadProcess_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
mAdapter.NotifyDataSetChanged();
progress.Dismiss();
Console.WriteLine("3333333333333");
}
private void DownloadProcess_DoWork(object sender, DoWorkEventArgs e)
{
urlT = net.DownloadString("http://articee.livescore31.com/api/json_load10.php");
jsonRootNews = JsonConvert.DeserializeObject<List<JsonRootNews>>(urlT);
for (int i = 0; i < jsonRootNews[0].item.Count; i++)
{
mRootItem.Add(new RowItems() { Name = jsonRootNews[0].item[i].judul, Image = jsonRootNews[0].item[i].img_Url, ShortTitle = jsonRootNews[0].item[i].short_title });
}
//SetUpRecyclerView(e.Argument as RecyclerView);
Console.WriteLine("2222222222222222");
}
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View row = inflater.Inflate(Resource.Layout.Fragment3, container, false);
RecyclerView mRecyclerView = row.FindViewById<RecyclerView>(Resource.Id.recyclerView);
mLayoutManager = new LinearLayoutManager(Context);
mRecyclerView.SetLayoutManager(new LinearLayoutManager(Context));
var scrollListener = new scroll(new LinearLayoutManager(Context));
mRecyclerView.AddOnScrollListener(scrollListener);
mRecyclerView.SetAdapter(mAdapter);
scrollListener.mDoText += () =>
{
if (isReload)
{
BackgroundWorker doitSomeThing = new BackgroundWorker();
doitSomeThing.DoWork += DoitSomeThing_DoWork;
doitSomeThing.RunWorkerCompleted += DoitSomeThing_RunWorkerCompleted;
doitSomeThing.RunWorkerAsync();
isReload = false;
}
};
return row;
}
private void SetUpRecyclerView(RecyclerView mRecyclerView)
{
//LinearLayoutManager mLinear = new LinearLayoutManager(Context);
//mLayoutManager = new LinearLayoutManager(Context);
//mLayoutManager.Orientation = LinearLayoutManager.Horizontal;
//var ss = new LinearLayoutManager(Context);
i++;
Console.WriteLine("ON VIEW ------------------"+i);
mRootItem = new List<RowItems>();
mAdapter = new RecyclerAdapter(mRootItem, Context, mRecyclerView);
var scrollListener = new scroll(mLayoutManager);
mRecyclerView.SetLayoutManager(new LinearLayoutManager(Context));
mRecyclerView.AddOnScrollListener(scrollListener);
mRecyclerView.SetAdapter(mAdapter);
mAdapter.NotifyDataSetChanged();
scrollListener.mDoText += () =>
{
if (isReload)
{
BackgroundWorker doitSomeThing = new BackgroundWorker();
doitSomeThing.DoWork += DoitSomeThing_DoWork;
doitSomeThing.RunWorkerCompleted += DoitSomeThing_RunWorkerCompleted;
doitSomeThing.RunWorkerAsync();
isReload = false;
}
};
}
private void DoitSomeThing_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
isReload = true;
}
private void DoitSomeThing_DoWork(object sender, DoWorkEventArgs e)
{
Random r = new Random();
int random = r.Next(0, 1000);
urlT = net.DownloadString("http://articee.livescore31.com/api/json_load5.php?limit=" + loadNow + "&id=" + random);
jsonRootNews = JsonConvert.DeserializeObject<List<JsonRootNews>>(urlT);
for (int i = 0; i < jsonRootNews[0].item.Count; i++)
{
mRootItem.Add(new RowItems() { Name = jsonRootNews[0].item[i].judul, Image = jsonRootNews[0].item[i].img_Url, ShortTitle = jsonRootNews[0].item[i].short_title });
Console.WriteLine("COMPLETE");
}
mAdapter.NotifyDataSetChanged();
loadNow += 2;
Console.WriteLine("-----------------------------" + loadNow.ToString());
}
}
public class RecyclerAdapter : RecyclerView.Adapter
{
public List<RowItems> mItems;
public Context mContext;
public RecyclerView mRecyclerView;
public RecyclerAdapter(List<RowItems> items, Context context, RecyclerView recyclerView)
{
mItems = items;
mContext = context;
mRecyclerView = recyclerView;
}
public class MyView : RecyclerView.ViewHolder
{
public View mMainView { get; set; }
public TextView mName { get; set; }
public ImageView mImage { get; set; }
public TextView mShortTitle { get; set; }
public Button button;
public MyView(View view) : base(view)
{
mMainView = view;
}
}
public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
{
View row = LayoutInflater.From(parent.Context).Inflate(Resource.Layout.row_news, parent, false);
//mRecyclerView = (RecyclerView)row.FindViewById(Resource.Id.btnReadMore);
TextView txtName = row.FindViewById<TextView>(Resource.Id.txtJudul);
ImageView ImageView = row.FindViewById<ImageView>(Resource.Id.imgThumbnail);
TextView txtShortMessage = row.FindViewById<TextView>(Resource.Id.txtShortTitle);
Button mButton1 = row.FindViewById<Button>(Resource.Id.btnReadMore);
MyView view = new MyView(row) { mName = txtName, mImage = ImageView, mShortTitle = txtShortMessage, button = mButton1 };
return view;
}
public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int position)
{
MyView myHolder = holder as MyView;
myHolder.mMainView.Click += MMainView_Click;
myHolder.button.Click += (sender, e) => { MyHandler(sender, e, position); };
myHolder.mName.Text = mItems[position].Name;
Picasso.With(mContext).Load(mItems[position].Image).Into(myHolder.mImage);
myHolder.mShortTitle.Text = mItems[position].ShortTitle;
}
//BUTTON READ MORE ==========================================================================================================
void MyHandler(object sender, EventArgs e, int pos)
{
try
{
Console.WriteLine(mItems[pos].Name);
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}
}
//=============================================================================================================================
private void MMainView_Click(object sender, EventArgs e)
{
try
{
int position = mRecyclerView.GetChildPosition((View)sender);
//int indexPosition = (mEmails.Count - 1) - position;
//Console.WriteLine(mEmails[indexPosition].Name);
Console.WriteLine(mItems[2].Name);
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
Console.WriteLine(mItems.Count);
}
}
public override int ItemCount
{
get
{
return mItems.Count;
}
}
}
public class scroll : RecyclerView.OnScrollListener
{
public delegate void DoSomething();
public DoSomething mDoText;
public LinearLayoutManager mLayoutManager;
public scroll(LinearLayoutManager layoutManager)
{
mLayoutManager = layoutManager;
}
public override void OnScrolled(RecyclerView recyclerView, int dx, int dy)
{
base.OnScrolled(recyclerView, dx, dy);
var visibleItemCount = recyclerView.ChildCount;
var totalItemCount = recyclerView.GetAdapter().ItemCount;
var latVisible = mLayoutManager.FindLastCompletelyVisibleItemPosition();
var pasVisibleItem = mLayoutManager.FindFirstVisibleItemPosition();
if ((visibleItemCount + pasVisibleItem) >= (totalItemCount))
{
mDoText.Invoke();
}
else
{
Console.WriteLine("visibleItemCount + pasVisibleItem = " + (visibleItemCount + pasVisibleItem));
}
}
}
}`
回答1:
You can get the LinearLayoutManager from the RecyclerView by calling
var layoutManager = (LinearLayoutManager)recyclerView.GetLayoutManager();
Therefore, you could use this in your ScrollListener instead of passing the created LinearLayoutManager:
public class scroll : RecyclerView.OnScrollListener
{
public delegate void DoSomething();
public DoSomething mDoText;
public scroll()
{
}
public override void OnScrolled(RecyclerView recyclerView, int dx, int dy)
{
base.OnScrolled(recyclerView, dx, dy);
var visibleItemCount = recyclerView.ChildCount;
var totalItemCount = recyclerView.GetAdapter().ItemCount;
// GET LAYOUT MANAGER
var mLayoutManager = (LinearLayoutManager)recyclerView.GetLayoutManager();
var latVisible = mLayoutManager.FindLastCompletelyVisibleItemPosition();
var pasVisibleItem = mLayoutManager.FindFirstVisibleItemPosition();
if ((visibleItemCount + pasVisibleItem) >= (totalItemCount))
{
mDoText.Invoke();
}
else
{
Console.WriteLine("visibleItemCount + pasVisibleItem = " + (visibleItemCount + pasVisibleItem));
}
}
}
来源：https://stackoverflow.com/questions/41354809/how-to-get-linearlayoutmanager-from-recyclerview