在回收站视图中加载大量项目 [英] Loading large number of items in recycler view
问题描述
我在片段中有一个回收站视图，基本上我想在回收站视图中加载歌曲列表.回收站视图的每一行都包含一个 imageview (用于专辑封面)和 textview (代表歌曲名称).当数据集很大时(即歌曲太多)，回收器视图滞后并且应用程序最终给出ANR时，我遇到了麻烦.我正在使用Glide在每行的图像视图中加载专辑封面. Google音乐播放器如何能够显示大量歌曲而没有任何滞后?
I have a recycler view within a fragment and basically I m trying to load song list in the recycler view .Each row of recycler view contains an imageview (for album art) and textview ( for song name). I am having trouble when the size of the dataset is huge, that is when there are too many songs, the recycler view lags and the app ends up giving an ANR.I am using Glide to load album arts in each row's imageview. How is google music player able to show such large number of songs without any lag?
修改: 这是我的 SongsFragment
public class SongsFragment extends Fragment {
static {
AppCompatDelegate.setCompatVectorFromResourcesEnabled(true);
}
ProgressBar progressBar; // progress bar to show after every 30 items
NestedScrollView nestedScrollView; //for smooth scrolling of recyclerview as well as to detect the end of recyclerview
RecyclerView recyclerView;
ArrayList<Song> songMainList = new ArrayList<>(); //partial list in which items are added
ArrayList<Song> songAllList = new ArrayList<>(); //Complete List of songs
SongAdapter songsAdapter;
private LinearLayoutManager layoutManager;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_songs, container, false);
nestedScrollView = (NestedScrollView) rootView.findViewById(R.id.nestedScrollView);
progressBar = (ProgressBar) rootView.findViewById(R.id.progressBar);
String songJson = getActivity().getIntent().getStringExtra("songList");
songAllList = new Gson().fromJson(songJson, new TypeToken<ArrayList<Song>>() {
}.getType());
//Getting list of all songs in songAllList
if (songAllList.size() > 30) {
songMainList = new ArrayList<>(songAllList.subList(0,30));
} else {
songMainList = songAllList;
}
//if size of fetched songAllList>30 then add only 30 rows to songMainList
recyclerView = (RecyclerView) rootView.findViewById(R.id.songs);
int spanCount = 1; // 2 columns
int spacing = 4; // 50px
recyclerView.addItemDecoration(new GridItemDecoration(spanCount, spacing, true));
recyclerView.setHasFixedSize(true);
recyclerView.setNestedScrollingEnabled(false);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
songsAdapter = new SongAdapter(getActivity(), songMainList, recyclerView);
nestedScrollView.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
@Override
public void onScrollChanged() {
View view = (View) nestedScrollView.getChildAt(nestedScrollView.getChildCount() - 1);
int diff = (view.getBottom() - (nestedScrollView.getHeight() + nestedScrollView
.getScrollY()));
if (diff == 0) { //NestedScrollView scrolled to bottom
progressBar.setVisibility(View.VISIBLE); //show progressbar
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
if (songMainList.size() < songAllList.size()) {
int x = 0, y = 0;
if ((songAllList.size() - songMainList.size()) >= 30) {
x = songMainList.size();
y = x + 30;
} else {
x = songMainList.size();
y = x + songAllList.size() - songMainList.size();
}
for (int i = x; i < y; i++) {
songMainList.add(songAllList.get(i)); //Adding new items from songAllList to songMainList one by one
songsAdapter.notifyDataSetChanged();
}
}
progressBar.setVisibility(View.GONE);
}
}, 1500);
}
}
});
recyclerView.setAdapter(songsAdapter);
return rootView;
}
}
这是我的 RecyclerViewAdapter 和 viewholder
public class SongAdapter extends RecyclerView.Adapter {
private List<Song> songsList;
private Context c;
private RecyclerView.ViewHolder holder;
public SongAdapter(Context context) {
mainActivityContext = context;
}
public SongAdapter(Context context, List<Song> songs, RecyclerView recyclerView) {
songsList = songs;
LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
c = context;
}
public SongAdapter getInstance() {
return SongAdapter.this;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.song_list_row, parent, false);
return new SongViewHolder(view,c);
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
if (holder instanceof SongViewHolder) {
Song song = songsList.get(position);
this.holder = holder;
String name = song.getName();
String artist = song.getArtist();
String imagepath = song.getImagepath();
((SongViewHolder) holder).name.setText(name);
((SongViewHolder) holder).artist.setText(artist);
if (!imagepath.equalsIgnoreCase("no_image")) //if the album art has valid imagepath for this song
Glide.with(c).load(imagepath)
.centerCrop()
.into(((SongViewHolder) holder).iv);
else
((SongViewHolder) holder).iv.setImageResource(R.drawable.empty);
((SongViewHolder) holder).song = song;
}
}
@Override
public int getItemCount() {
return songsList.size();
}
static class SongViewHolder extends RecyclerView.ViewHolder{
ImageView iv;
TextView name, artist;
CardView songListCard;
private Context ctx;
private OnLongPressListener mListener;
SongViewHolder(View v, Context context) {
super(v);
this.ctx = context;
iv= (ImageView) v.findViewById(R.id.album_art);
name= (TextView) v.findViewById(R.id.name);
artist= (TextView) v.findViewById(R.id.artist_mini);
songListCard = (CardView) v.findViewById(R.id.song_list_card);
}
}
只有150-200个项目时recyclerview可以正常工作，但是当达到600-700个项目时，整个应用程序速度会变慢.可能是因为我在 onBindViewHolder 中使用 glide 的方式吗?
The recyclerview works fine when there are only 150-200 items but when reaching to 600-700 items , the whole app slows down. Could this be because of the way I have used glide in onBindViewHolder?
推荐答案
通过在recyclerview上删除NestedScrollView解决了该问题. nestedscrollview不允许调用recyclerview.addOnScrollListener()，因此我在加载更多项目时滞后了. 这是我如何为RecyclerView实现loadOnScroll-
Solved the problem by removing the NestedScrollView over the recyclerview. The nestedscrollview was not allowing the recyclerview.addOnScrollListener() to be called because of which I was getting a lag on loading more items. Here is how i implemented the loadOnScroll for RecyclerView-
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (!recyclerView.canScrollVertically(1))
onScrolledToBottom();
}
});
private void onScrolledToBottom() {
if (songMainList.size() < songAllList.size()) {
int x, y;
if ((songAllList.size() - songMainList.size()) >= 50) {
x = songMainList.size();
y = x + 50;
} else {
x = songMainList.size();
y = x + songAllList.size() - songMainList.size();
}
for (int i = x; i < y; i++) {
songMainList.add(songAllList.get(i));
}
songsAdapter.notifyDataSetChanged();
}
}
这篇关于在回收站视图中加载大量项目的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
