RecyclerView sliding up pages, linearLayoutManager. FindFirstVisibleItemPosition why not () to obtain the value of the change?

Slipping time is will change, such as from 1 to 9, slip up has been stuck in 9, (specifically: it jumped to 8, and then immediately into 9)

Please help me to look at: why this happens? Code:

The class PdfScrollListener extends RecyclerView. OnScrollListener {
Int currentPage=0;
Int lastPage=0;
PdfActivity PdfActivity;

Public PdfScrollListener PdfActivity (PDF) {
PdfActivity=PDF;
}

@ Override
Public void onScrollStateChanged (@ NonNull RecyclerView RecyclerView, int newState because) {
The e (" Position ", "============:" + linearLayoutManager. FindFirstVisibleItemPosition ());

LinearLayoutManager LinearLayoutManager=(LinearLayoutManager) recyclerView. GetLayoutManager ();
If (((LinearLayoutManager) recyclerView getLayoutManager ()). FindFirstVisibleItemPosition ()==1) {
CurrentPage=0;
} else {
CurrentPage=((LinearLayoutManager) recyclerView getLayoutManager ()). FindFirstVisibleItemPosition ();
}

//insert again after two pages

If (currentPage & gt; LastPage & amp; & CurrentPage + 2 & lt; PdfActivity. PageCount) {//judgment does not exceed the total number of pages in advance to insert two page
PdfActivity. GoDown (currentPage);
RecyclerView. GetAdapter (.) notifyItemInserted (currentPage + 2);
PdfActivity. DeletePage (currentPage);

}

If (currentPage & lt; LastPage & amp; & CurrentPage - 2 & gt;=0 & amp; & RecyclerView. GetAdapter (.) getItemId (currentPage - 2)==recyclerView. NO_ID) {
RecyclerView. GetAdapter (.) notifyItemInserted (currentPage - 3);
}
RecyclerView. Invalidate ();
LastPage=currentPage;

}

}

CodePudding user response:

Done, because recyclerView. GetAdapter () notifyItemInserted (currentPage - 3) and insert the item of

But I will not insert item, as long as it is ok to modify the data source, to use. NotifyDataSetChanged ()