Colleagues, new day and new question. It slows down the scrolling of the list, as if it is a very hard game, and I have a weak video card and there is no RAM in the computer at all. Moreover, it slows down both at the first scrolling down (when creating view holders) and when returning to already existing elements. The number of elements in the list is limited, each element consists of 3 ImageView (48x48, 16x16, 48x48) and 3 TextView. Two of the three vector images. Data loads from the Internet and caches to the list (ArrayList), a bitmap image (cover) is loaded via Glide.
Adapter code:

private static ArrayList <Book> books; static Context context; final static class ViewHolder extends RecyclerView.ViewHolder { TextView name; TextView author; TextView length; ImageView icon; ImageView bookType; ImageView bookFace; ViewHolder (View view) { super (view); context = view.getContext(); this.name = view.findViewById (R.id.name); this.author = view.findViewById (R.id.author); this.length = view.findViewById (R.id.timeOrPages); this.icon = view.findViewById (R.id.icon); this.bookType = view.findViewById (R.id.bookType); this.bookFace = view.findViewById (R.id.bookFace); view.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { ListActivity listActivity = new ListActivity (); int position = getLayoutPosition(); if (MainActivity.onLine) { if (books.get(position) instanceof AudioBook) { BookActivity.bookType = "audio"; BookActivity.book = books.get (position); if (books.get (position).getChapters() != null && books.get (position).getChapters().size() == 1) { BookActivity.actualPosition = (int) books.get (position).getChapters().get(0).currentPosition; } BookActivity.actualChapter = getActualChapter (position); BookActivity.dataHttp = books.get (position).getSystemName(); context.startActivity(new Intent(context, BookActivity.class)); listActivity.books = null; } else { BookActivity.bookType = "text"; BookActivity.book = books.get (position); BookActivity.actualChapter = getActualChapter(position); BookActivity.dataHttp = books.get (position).getSystemName(); listActivity.books = null; context.startActivity(new Intent(context, BookActivity.class)); } } else { Log.d (LOG_TAG, "chapter 0 = " + books.get (position).getChapters()); String [] path = books.get (position).getChapters().get (0).getAddress().split ("/"); String [] bookData = path [path.length - 2].split ("_"); switch (path [path.length - 3]) { case ("audio"): BookActivity.bookType = "audio"; BookActivity.title = bookData [1]; BookActivity.author = bookData [2]; BookActivity.actualChapter = getActualChapter(position); BookActivity.book = getBook (bookData [1], "audio"); context.startActivity(new Intent(context, BookActivity.class)); listActivity.books = null; break; case ("text"): BookActivity.bookType = "text"; BookActivity.title = bookData [1]; BookActivity.author = bookData [2]; BookActivity.actualChapter = getActualChapter(position); BookActivity.book = getBook (bookData [1], "text"); context.startActivity(new Intent(context, BookActivity.class)); listActivity.books = null; break; } } } }); } } public SomeAdapter (ArrayList <Book> books) { this.books = books; } @Override public final SomeAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { Log.d (LOG_TAG, "onCreate viewHolder"); View v; if (MainActivity.night) v = LayoutInflater.from (parent.getContext()).inflate(R.layout.list_item_night, parent, false); else v = LayoutInflater.from (parent.getContext()).inflate(R.layout.list_item, parent, false); return new ViewHolder (v); } @Override public final void onBindViewHolder(final NewBiblioAdapter.ViewHolder holder, final int position) { holder.name.setText (books.get (position).getName()); holder.author.setText (books.get (position).getAuthor()); holder.length.setText(books.get(position).getLength()); if (books.get (position) instanceof AudioBook) { holder.icon.setBackgroundResource(R.drawable.iconaudio); holder.bookType.setBackgroundResource(R.drawable.iconaudio); } else { holder.icon.setBackgroundResource (R.drawable.icontext); holder.bookType.setBackgroundResource (R.drawable.icontext); } try { Glide.with (context) .load (books.get (position).getCoverPreview ()) .into (holder.bookFace); } catch (Exception e) { Log.d (LOG_TAG, "thread exception", e); } } @Override public final void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) { super.onAttachedToRecyclerView(recyclerView); } @Override public final int getItemCount() { if (books == null) return 0; else return books.size(); } private static Book getBook (String bookName, String type) { for (int i = 0; i < books.size(); i++) { if (books.get (i).getName().equalsIgnoreCase (bookName)) { return books.get(i); } } if (type.equalsIgnoreCase ("audio")) return new AudioBook (); else return new TextBook (); } private static int getActualChapter (int position) { if (books.get (position).getChapters() != null && books.get (position).getChapters().size() == 1) { return (int) books.get(position).getChapters().get(0).getId(); } else return 0; } }

List Item XML Code:

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:theme="@style/SomeTheme" android:background="@color/colorBack" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal"> <ImageView android:id="@+id/bookFace" android:layout_width="48dp" android:layout_height="48dp" android:layout_gravity="center_vertical" android:layout_margin="8dp" /> <android.support.constraint.ConstraintLayout android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1"> <TextView android:id="@+id/name" android:layout_width="match_parent" android:layout_height="wrap_content" android:textSize="16sp" app:layout_constraintTop_toTopOf="parent" /> <TextView android:id="@+id/author" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginBottom="16dp" android:textSize="10sp" app:layout_constraintTop_toBottomOf="@id/name" /> <ImageView android:id="@+id/icon" android:layout_width="18dp" android:layout_height="15dp" android:layout_marginTop="8dp" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintTop_toBottomOf="@id/author" /> <TextView android:id="@+id/timeOrPages" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="8dp" android:layout_marginStart="8dp" android:layout_marginTop="8dp" app:layout_constraintLeft_toRightOf="@id/icon" app:layout_constraintTop_toBottomOf="@id/author" /> </android.support.constraint.ConstraintLayout> <ImageView android:id="@+id/bookType" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_vertical" android:layout_margin="8dp" /> </LinearLayout>

The second (night) differs only in colors.
RecyclerView call code:

 recyclerView = findViewById (R.id.recyclerView); RecyclerView.LayoutManager layoutManager = new LinearLayoutManager (ListActivity.this); recyclerView.setLayoutManager (layoutManager); recyclerView.setHasFixedSize (true); recyclerView.setNestedScrollingEnabled (false); DividerItemDecoration verticalDividerDecorator = new DividerItemDecoration (ListActivity.this, DividerItemDecoration.VERTICAL); Drawable horizontalDivider; if (MainActivity.night) horizontalDivider = ContextCompat.getDrawable (ListActivity.this, R.drawable.divider_night); else horizontalDivider = ContextCompat.getDrawable (ListActivity.this, R.drawable.divider); try { verticalDividerDecorator.setDrawable(horizontalDivider); recyclerView.addItemDecoration (verticalDividerDecorator); } catch (Exception e) { Log.d (LOG_TAG, "divider exception", e); } adapter = new SomeAdapter((ArrayList<Book>) books); recyclerView.setAdapter(adapter);

What is most interesting is that it does not slow down on all phones and it does not depend on the parameters of the phone (on my own, more relaxed, flies, on the phone of a colleague, more powerful, lags terribly, it’s already disgusting to look).

  • Custom fonts do not use? - Jarvis_J
  • No, I do not use. - Artyom Balsan

2 answers 2

I found a problem. Perhaps this is not a 100 percent solution, however, most of the issue is exactly resolved. The problem was in Over Draw (in redrawing elements). Behind my list there were two more items in full screen - the main theme of the application and the background that I set to download and then did not remove (did not consider it important). For those who have already dug in this direction: I also looked at this question before, and simply did not think that only two (although I thought that I’m actually one, my jamb) additional layers can raise the FPS to 4-5 ( !) times It turned out that in the question list is very important.
What I watched to get to the solution - monitored FPS. Built-in Android (Developer mode - GPU processing profile - on the screen in the form of strips). Link to the video with a specialist from google https://www.youtube.com/watch?v=VzYkVL1n4M8&index=24&list=PLWz5rJ2EKKc9CBxr3BVjPTPoDPLdPIFCE
And, of course, Over Draw itself, that is, overlay layers, the same Developer Mode - Debugging the GPU overshoot - Show overlay areas. FPS for good work is less than 16. My result is 5-10 when scrolling through the list. Grateful to everyone for their time and attention.

    Download in onBindViewHolder (). This method should not be heavy loads, perhaps this is the reason.

     try { Glide.with (context) .load (books.get (position).getCoverPreview ()) .into (holder.bookFace); } catch (Exception e) { Log.d (LOG_TAG, "thread exception", e);

    Make a check to find the necessary data in the cache, if it is, then load it from the cache in this method, if not, move the data from Glide to a separate stream.

    • Thank you for your reply. However, even if you completely remove the loading of pictures into the adapter (and in general in RecyclerView) - nothing changes ... - Artyom Balzan
    • Most likely you have a problem in onBindViewHolder (), try to comment out the contents of this method and see if the lags disappear. If they do not disappear, then you have a problem in the ViewHolder designer. - Ivan Andreevich