recyclerview滚动并保持在旧位置不要转到顶部 [英] recyclerview scroll and stay in old position dont go top
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问题描述
我的问题是当我在回收视图中滚动数据时，所以加载了新数据，但问题是当新数据正在加载时，回收视图从第一个产品开始，
my problem is when I scroll my data in recycle view So new data loading but problem is when new data is loading my recycle view start from first product,
我需要保持旧的位置并只滚动新数据，而不是滚动所有新旧数据
I need to stay old position and scroll only new data not all data old and new
当前，我正在添加文件adeptoer文件和主文件的完整代码，
currently I am adding full code of my file adeptoer file and home file,
public class adepter extends RecyclerView.Adapter<adepter.viewholder> {
private Context mCtx;
private List<Product> productList;
public adepter(Context mCtx, List<Product> productList) {
this.mCtx = mCtx;
this.productList = productList;
}
@NonNull
@Override
public adepter.viewholder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
LayoutInflater inflater=LayoutInflater.from(mCtx);
View v =inflater.inflate(R.layout.product_list, parent, false);
final viewholder vh = new viewholder(v);
vh.itemView.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Product product = productList.get(vh.getAdapterPosition());
//do the page opening here
Intent intent = new Intent(mCtx, product_info.class);
intent.putExtra("id",product.getId());
mCtx.startActivity(intent);
}
});
return vh;
}
@Override
public void onBindViewHolder(@NonNull adepter.viewholder holder, int position) {
Product product = productList.get(position);
//loading the image
Glide.with(mCtx)
.load(product.getImage())
.into(holder.imageView);
holder.textViewTitle.setText(product.getTitle());
holder.textViewShortDesc.setText(product.getShortdesc());
holder.textViewtype.setText(String.valueOf(product.getType()));
holder.textViewPrice.setText("Rs: "+String.valueOf(product.getPrice()));
}
@Override
public int getItemCount() {
return productList.size();
}
public class viewholder extends RecyclerView.ViewHolder{
TextView textViewTitle, textViewShortDesc, textViewtype, textViewPrice;
ImageView imageView;
public viewholder(@NonNull View itemView) {
super(itemView);
textViewTitle = itemView.findViewById(R.id.textViewTitle);
textViewShortDesc = itemView.findViewById(R.id.textViewShortDesc);
textViewtype = itemView.findViewById(R.id.textViewRating);
textViewPrice = itemView.findViewById(R.id.textViewPrice);
imageView = itemView.findViewById(R.id.imageView);
}
}
}
public class home extends AppCompatActivity {
//a list to store all the products
List<Product> productList;
//the recyclerview
RecyclerView recyclerView;
ProgressBar Pbar;
GridLayoutManager manager;
int token = 1;
Boolean isScrolling = false;
int currentItems, totalItems, scrollOutItems;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
Pbar = findViewById(R.id.progressBar1);
//getting the recyclerview from xml
recyclerView = findViewById(R.id.recylcerView);
recyclerView.setHasFixedSize(true);
manager = new GridLayoutManager(this, 2);
recyclerView.setLayoutManager(manager);
//initializing the productlist
productList = new ArrayList<>();
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if(newState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL)
{
isScrolling = true;
}
}
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
currentItems = manager.getChildCount();
totalItems = manager.getItemCount();
scrollOutItems = manager.findFirstVisibleItemPosition();
if(isScrolling && (currentItems + scrollOutItems == totalItems))
{
isScrolling = false;
token++;
getData();
}
}
});
getData();
}
private void getData(){
String url = "https://shop.com/index.php";
url = url+ "&pg="+ String.valueOf(token);
Pbar.setVisibility(View.VISIBLE);
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// Toast.makeText(getApplicationContext(),"volly ok ",Toast.LENGTH_LONG).show();
try {
//converting the string to json array object
JSONArray array = new JSONArray(response);
//traversing through all the object
for (int i = 0; i < array.length(); i++) {
//getting product object from json array
JSONObject product = array.getJSONObject(i);
//adding the product to product list
productList.add(new Product(
product.getInt("id"),
product.getString("title"),
product.getString("shortdesc"),
product.getString("type"),
product.getString("price"),
product.getString("image")
));
}
// Toast.makeText(getApplicationContext(),productList+ "volly ok ",Toast.LENGTH_LONG).show();
adepter a = new adepter(home.this, productList);
recyclerView.setAdapter(a);
Pbar.setVisibility(View.GONE);
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "Server Error" ,Toast.LENGTH_LONG).show();
}
});
//adding our stringrequest to queue
Volley.newRequestQueue(this).add(stringRequest);
}
}
推荐答案
尝试一下:
public class home extends AppCompatActivity {
//a list to store all the products
List<Product> productList;
//the recyclerview
RecyclerView recyclerView;
adepter a;
ProgressBar Pbar;
GridLayoutManager manager;
int token = 1;
Boolean isScrolling = false;
int currentItems, totalItems, scrollOutItems;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
Pbar = findViewById(R.id.progressBar1);
//getting the recyclerview from xml
recyclerView = findViewById(R.id.recylcerView);
recyclerView.setHasFixedSize(true);
manager = new GridLayoutManager(this, 2);
recyclerView.setLayoutManager(manager);
//initializing the productlist
productList = new ArrayList<>();
a = new adepter(home.this, productList);
recyclerView.setAdapter(a);
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if(newState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL)
{
isScrolling = true;
}
}
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
currentItems = manager.getChildCount();
totalItems = manager.getItemCount();
scrollOutItems = manager.findFirstVisibleItemPosition();
if(isScrolling && (currentItems + scrollOutItems == totalItems))
{
isScrolling = false;
token++;
getData();
}
}
});
getData();
}
private void getData(){
String url = "https://shop.com/index.php";
url = url+ "&pg="+ String.valueOf(token);
Pbar.setVisibility(View.VISIBLE);
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// Toast.makeText(getApplicationContext(),"volly ok ",Toast.LENGTH_LONG).show();
try {
//converting the string to json array object
JSONArray array = new JSONArray(response);
//traversing through all the object
for (int i = 0; i < array.length(); i++) {
//getting product object from json array
JSONObject product = array.getJSONObject(i);
//adding the product to product list
productList.add(new Product(
product.getInt("id"),
product.getString("title"),
product.getString("shortdesc"),
product.getString("type"),
product.getString("price"),
product.getString("image")
));
}
a.notifyDataSetChanged();
Pbar.setVisibility(View.GONE);
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "Server Error" ,Toast.LENGTH_LONG).show();
}
});
//adding our stringrequest to queue
Volley.newRequestQueue(this).add(stringRequest);
}
}
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