您好，我的应用目前遇到了一个大问题。我有一个 recyclerView，我用来自 back4app 的数据填充适配器。我已经与他们核实过，我提出的查询没有延迟。无论如何，当我加载使用两行网格布局模式呈现回收站 View 的 fragment 时，问题如下。
这是在 onCreateViewHolder 中膨胀的 XML
当我在我的模拟器或手机中运行该应用程序时，我在我的屏幕上看到了这种行为，几毫秒后图像显示正确，但这已经转化为糟糕的用户体验，导致它的行为缓慢。
这是我的 fragment ......
public class PropiedadesInmobiliariasFragment extends Fragment {
private LinearLayoutManager layoutManager;
RecyclerView recyclerInmobiliarias;
ParseObject queryEmpresa;
ParseObject empresa;
String stringEmpresa;
List<ParseObject> allItems;
FragmentManager fm;
ProgressBar pb;
public PropiedadesInmobiliariasFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_propiedades_inmobiliarias, container, false);
pb = view.findViewById(R.id.progress_bar_inmo);
recyclerInmobiliarias=(RecyclerView)view.findViewById(R.id.recycler_inmobiliarias);
//pb.setVisibility(View.VISIBLE);
recyclerInmobiliarias.setVisibility(View.GONE);
pb.setVisibility(View.VISIBLE);
allItems=new ArrayList<>();
queryEmpresa();
layoutManager=new GridLayoutManager(getContext(),2);
recyclerInmobiliarias.setLayoutManager(layoutManager);
recyclerInmobiliarias.setHasFixedSize(true);
recyclerInmobiliarias.addOnItemTouchListener(new RecyclerTouchListener(getActivity(), recyclerInmobiliarias, new RecyclerTouchListener.ClickListener() {
@Override
public void onClick(View view, int position) {
ParseObject item=allItems.get(position);
String selectedObjectId= item.getObjectId();
String nombrePro=item.getString("NombrePropiedad");
ParseFile object1 = item.getParseFile("imagenPrincipal");
ParseFile imagen1 = item.getParseFile("imagen1");
ParseFile imagen2 = item.getParseFile("imagen2");
ParseFile imagen3 = item.getParseFile("imagen3");
ParseFile imagen4 = item.getParseFile("imagen4");
ParseFile imagen5 = item.getParseFile("imagen5");
ParseFile imagen6 = item.getParseFile("imagen6");
ParseFile imagen7 = item.getParseFile("imagen7");
ParseFile imagen8 = item.getParseFile("imagen8");
String precio=item.getString("Precio");
String numHabita=item.getString("numeroDeHabitaciones");
String metrosCuadrados=item.getString("metrosCuadrados");
String numeroBanos=item.getString("numeroBanos");
String descrip=item.getString("descripcionAdicionalPropiedad");
String admin=item.getString("valorAdministracion");
String numPar=item.getString("Parqueaderos");
Bundle bundle=new Bundle();
bundle.putString("objectId",selectedObjectId);
bundle.putString("Nombre",nombrePro);
bundle.putString("primeraFoto", object1.getUrl());
bundle.putString("precio",precio);
bundle.putString("numHab",numHabita);
bundle.putString("metrosCua",metrosCuadrados);
bundle.putString("numBanos",numeroBanos);
bundle.putString("des",descrip);
bundle.putString("admin",admin);
bundle.putString("parq",numPar);
Intent intent = new Intent(getActivity(), DetalleInmobiliaria.class);
intent.putExtra("objectId", selectedObjectId);
intent.putExtra("Nombre", nombrePro);
intent.putExtra("primeraFoto", object1.getUrl());
intent.putExtra("precio", precio);
intent.putExtra("numHab", numHabita);
intent.putExtra("metrosCua", metrosCuadrados);
intent.putExtra("numBanos", numeroBanos);
intent.putExtra("des", descrip);
intent.putExtra("admin", admin);
intent.putExtra("parq", numPar);
startActivity(intent);
}
@Override
public void onLongClick(View view, int position) {
}
}));
return view;
}
private void queryEmpresa(){
/**Ojo no es que no este sirviendo el metodo sino que el tipo de empresa asignado al usuario
* no concuerda para que llene el recycler*/
ParseQuery<ParseUser> query = ParseUser.getQuery();
query.whereEqualTo("objectId",ParseUser.getCurrentUser().getObjectId());
query.include("Empresa");
query.getInBackground(ParseUser.getCurrentUser().getObjectId(), new GetCallback<ParseUser>() {
public void done(ParseUser object, ParseException e) {
if (e == null) {
// object will be your user and you should be able to retrieve Empresa like this
empresa = object.getParseObject("Empresa");
stringEmpresa=empresa.getObjectId();
queryPropInmo();
} else {
// something went wrong. It would be good to log.
}
}
});
}
private void queryPropInmo(){
ParseQuery<ParseObject> query1 = ParseQuery.getQuery("PropiedadesInmobiliarias");
queryEmpresa=ParseObject.createWithoutData("Empresa",stringEmpresa);
query1.whereEqualTo("Empresa",queryEmpresa);
query1.include("Empresa");
query1.include("Imagenes");
query1.findInBackground(new FindCallback<ParseObject>() {
@Override
public void done(List<ParseObject> objects, ParseException e) {
if(objects!=null) {
for (ParseObject obj : objects
) {
allItems.add(obj);
}
}
InmobiliariaAdapter adapter = new InmobiliariaAdapter(getActivity(),allItems);
recyclerInmobiliarias.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
});
pb.setVisibility(View.GONE);
recyclerInmobiliarias.setVisibility(View.VISIBLE);
}
}
这是我的适配器...
public class InmobiliariaAdapter extends RecyclerView.Adapter<InmobiliariaAdapter.ViewHolder> {
Context context;
List<ParseObject> inmobiliList;
public InmobiliariaAdapter(Context context, List<ParseObject> inmobiliList) {
this.context = context;
this.inmobiliList = inmobiliList;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_carros, viewGroup, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull final ViewHolder viewHolder, final int position) {
ParseObject item = inmobiliList.get(position);
viewHolder.imagen.post(new Runnable() {
@Override
public void run() {
loadBitmap(item,viewHolder);
}
});
viewHolder.nombrePropInmobi.setText(item.getString("NombrePropiedad"));
}
@Override
public int getItemCount() {
return this.inmobiliList.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
ImageView imagen;
TextView nombrePropInmobi;
public ViewHolder(@NonNull View itemView) {
super(itemView);
imagen = (ImageView) itemView.findViewById(R.id.imgCarro);
nombrePropInmobi = (TextView) itemView.findViewById(R.id.txttitulo);
}
}
private void loadBitmap(ParseObject item, ViewHolder viewHolder){
ParseFile parseFile = item.getParseFile("imagenPrincipal");
if (parseFile != null) {
parseFile.getDataInBackground(new GetDataCallback() {
@Override
public void done(byte[] data, ParseException e) {
if (e == null) {
Bitmap bmp = BitmapFactory.decodeByteArray(data, 0, data.length);
if (bmp != null) {
viewHolder.imagen.setImageBitmap(bmp);
}
}
}
});
}
}
}
我没有使用模型类我只是从服务器获取我需要的东西我什至已经实现了各种尝试来解决这个问题，我尝试了进度条甚至处理程序我也考虑过实现异步任务但是查询.findInBackground 及其 done 方法已经处理异步调用，现在我担心随着 Runnable 的实现可能会转化为内存泄漏。这里真正的问题是应用程序首先显示来自 XML 的元素，这些元素在回收器 View 中的每个位置的适配器中膨胀。我想要完成的是只有当来自后端的图像真正完成加载时才会显示回收器 View 我真的不知道是什么原因造成的。目前该列表有 5 个项目，我不想用 3000 个项目来描绘它，:(，请帮助!!!!。
最佳答案
您可以使用 Glide 和 Picasso 等库来完成这项工作。这些是具有缓存能力的轻量级优秀库，可自动将图像的优化版本加载到您的 ImageView 中。它自动管理存储和删除缓存。直到那时，你的图片还没有下载，他们可以选择在下载你的图片时显示 placeholder 。它还可用于根据您的 ImageView 优化预览本地镜像。
像这样:
Glide.with(context)
.load("https://raw.githubusercontent.com/bumptech/glide/master/static/glide_logo.png")
.placeholder(R.drawable.circularProgressDrawable)
.into(IMAGE_VIEW)
关于android - 在 recyclerView 中呈现 imageView 延迟的问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/58869878/