我的应用程序中有更多功能，但当我到达列表末尾时，会加载新项目，但列表会自动滚动到列表的开头。
这是onload函数：
recyclerView.addOnScrollListener(new EndlessRecyclerOnScrollListener(mLayoutManager) {
@Override
public void onLoadMore(int current_page, int position) {
// do something...
Log.d("Yaeye!", "HElloyoyo");
SuperHeroes superHero = listSuperHeroes.get(position);
Log.d("we want url", superHero.getImageUrl());
imgoffset = superHero.getImageUrl();
// Do something
getData(0);
}
});
以下是从服务器收到的数据的解析：
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(url,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
//Dismissing progress dialog
// loading.dismiss();
//calling method to parse json array
parseData(response);
adapter.notifyDataSetChanged();
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
public int z;
//This method will parse json data
private int parseData(JSONArray array){
for(int i = 0; i<array.length(); i++) {
SuperHeroes superHero = new SuperHeroes();
CardAdapter car = new CardAdapter();
JSONObject json = null;
try {
json = array.getJSONObject(i);
superHero.setImageUrl(json.getString(Config.TAG_IMAGE_URL));
superHero.setProUrl(json.getString("pro_pic"));
Img =json.getString(Config.TAG_IMAGE_URL);
superHero.setName(json.getString(Config.TAG_NAME));
superHero.setRank(json.getInt(Config.TAG_RANK));
superHero.setstat(false);
Log.d("test",Img);
car.setImageUrl(Img);
} catch (JSONException e) {
e.printStackTrace();
}
adapter.notifyItemInserted(listSuperHeroes.size());
listSuperHeroes.add(superHero);
// adapter.notifyDataSetChanged();
loading=false;
}
EndlessRecyclerOnScrollListener来自here
package com.example.tatson.bila;
import android.app.ProgressDialog;
import android.content.ContentValues;
import android.content.Context;
import android.content.SharedPreferences;
import android.media.Image;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.example.tatson.bila.Register;
import com.android.volley.toolbox.ImageLoader;
import com.android.volley.toolbox.NetworkImageView;
import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Text;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.net.ssl.HttpsURLConnection;
public class CardAdapter extends RecyclerView.Adapter<CardAdapter.ViewHolder> {
private String imageUrl;
private ImageLoader imageLoader,imageLoader1;
private Context context;
String Load;
private static ClickListener c;
public static final String uu = "uu";
String number;
public static final String UserNum = "UserNum";
SharedPreferences sharedPref;
private String[] pos;
private int visibleThreshold = 5;
private int lastVisibleItem, totalItemCount;
private boolean loading;
private OnLoadMoreListener onLoadMoreListener;
// JSON parser class
JSONParser jsonParser = new JSONParser();
String url,imgoffset;
//testing from a real server:
private static final String LIKE_URL = "**";
//ids
private static final String TAG_SUCCESS = "success";
private static final String TAG_MESSAGE = "message";
List<SuperHeroes> superHeroes1;
//List of superHeroes
List<SuperHeroes> superHeroes;
private RecyclerView recyclerView;
public CardAdapter() {
}
public CardAdapter(List<SuperHeroes> superHeroes, Context context) {
super();
//Getting all the superheroes
this.superHeroes = superHeroes;
superHeroes1= superHeroes;
this.context = context;
sharedPref =context.getSharedPreferences(UserNum, 0);
number = sharedPref.getString(uu, "");
}
public void setImageUrl(String imageUrl) {
this.imageUrl = imageUrl;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.superheroes_list, parent, false);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
@Override
public void onBindViewHolder(ViewHolder holder, final int position) {
SuperHeroes superHero = superHeroes.get(position);
Log.d("position", String.valueOf(position));
Log.d("url", superHero.getImageUrl());
imageLoader = CustomVolleyRequest.getInstance(context).getImageLoader();
imageLoader.get(superHero.getImageUrl(), ImageLoader.getImageListener(holder.imageView, R.mipmap.ic_launcher, android.R.drawable.ic_dialog_alert));
imageLoader1 = CustomVolleyRequest.getInstance(context).getImageLoader();
imageLoader1.get(superHero.getProurl(), ImageLoader.getImageListener(holder.thumbNail, R.mipmap.ic_launcher, android.R.drawable.ic_dialog_alert));
Log.d("i am ob", "ob");
holder.imageView.setImageUrl(superHero.getImageUrl(), imageLoader);
holder.thumbNail.setImageUrl(superHero.getProurl(), imageLoader1);
holder.textViewName.setText(superHero.getName());
holder.textViewRank.setText(String.valueOf(superHero.getRank()));
if(superHero.getstat())
{
Log.d("i am g","g");
Log.d("i am value", String.valueOf(superHero.getstat()));
holder.like.setImageResource(R.drawable.plike);
}
else
{
Log.d("i am p","p");
holder.like.setImageResource(R.drawable.glike);
}
// holder.textViewPowers.setText(powers);
holder.like.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v) {
Log.d("i m in like","i m in like");
if(dudo!=null) {
Log.d("i m in like1", "i m in like1");
dudo.onlike(v, position);
}} });
}
public void refresh(List<SuperHeroes> superHeroes){
Log.d("Refresh","Refresh is called ");
this.superHeroes=superHeroes;
// notifyDataSetChanged();
}
@Override
public int getItemCount() {
return superHeroes.size();
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public NetworkImageView imageView;
public CircularNetworkImageView thumbNail;
public TextView textViewName;
public TextView textViewuserName;
public TextView textViewRank;
public ImageButton like;
public ViewHolder(View itemView) {
super(itemView);
imageView = (NetworkImageView) itemView.findViewById(R.id.imageViewHero);
textViewName = (TextView) itemView.findViewById(R.id.username_row);
//textViewuserName = (TextView) itemView.findViewById(R.id.username_row);
textViewRank = (TextView) itemView.findViewById(R.id.textViewRank);
thumbNail = (CircularNetworkImageView) itemView.findViewById(R.id.thumbnail);
like = (ImageButton) itemView.findViewById(R.id.button_like);
// itemView.setOnClickListener( this);
}
@Override
public void onClick(View v) {
if (dudo != null) {
Log.d("i m in like1", "i m in like1");
dudo.onlike(v, 2);
}
}
}
class LikeIt extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
*/
boolean failure = false;
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected String doInBackground(String... args) {
// TODO Auto-generated method stub
// Check for success tag
int success;
String Imgurl = Load;
Log.d("request!", number);
// try {
// Building Parameters
HashMap<String, String> Params = new HashMap<String, String>();
Params.put("Imgurl", Imgurl);
Params.put("user", number);
Log.d("request!", "starting");
String encodedStr = getEncodedData(Params);
//Will be used if we want to read some data from server
BufferedReader reader = null;
//Connection Handling
try {
//Converting address String to URL
URL url = new URL(LIKE_URL);
//Opening the connection (Not setting or using CONNECTION_TIMEOUT)
HttpURLConnection con = (HttpURLConnection) url.openConnection();
//Post Method
con.setRequestMethod("POST");
//To enable inputting values using POST method
//(Basically, after this we can write the dataToSend to the body of POST method)
con.setDoOutput(true);
OutputStreamWriter writer = new OutputStreamWriter(con.getOutputStream());
//Writing dataToSend to outputstreamwriter
writer.write(encodedStr);
//Sending the data to the server - This much is enough to send data to server
//But to read the response of the server, you will have to implement the procedure below
writer.flush();
//Data Read Procedure - Basically reading the data comming line by line
StringBuilder sb = new StringBuilder();
reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
String line;
while((line = reader.readLine()) != null) { //Read till there is something available
sb.append(line + "\n"); //Reading and saving line by line - not all at once
}
line = sb.toString(); //Saving complete data received in string, you can do it differently
//Just check to the values received in Logcat
Log.i("custom_check","The values :");
Log.i("custom_check", line);
} catch (Exception e) {
e.printStackTrace();
} finally {
if(reader != null) {
try {
reader.close(); //Closing the
} catch (IOException e) {
e.printStackTrace();
}
}
}
//Same return null, but if you want to return the read string (stored in line)
//then change the parameters of AsyncTask and return that type, by converting
//the string - to say JSON or user in your case
return null;
}
}
private String getEncodedData(Map<String,String> data) {
StringBuilder sb = new StringBuilder();
for(String key : data.keySet()) {
String value = null;
try {
value = URLEncoder.encode(data.get(key), "UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
if(sb.length()>0)
sb.append("&");
sb.append(key + "=" + value);
}
return sb.toString();
}
/**
* After completing background task Dismiss the progress dialog
**/
protected void onPostExecute() {
// dismiss the dialog once product deleted
}
private static ClickListener dudo ;
public interface ClickListener{
void onlike(View v,int pos);
}
public void setClickListener(ClickListener dudo){
this.dudo=dudo;
Log.d("i m in interface","i m in interface");
}
}
答案 0 :(得分：0)
修改你的for循环并再试一次
for(int i = 0; i<array.length(); i++) {
SuperHeroes superHero = new SuperHeroes();
CardAdapter car = new CardAdapter();
JSONObject json = null;
try {
json = array.getJSONObject(i);
superHero.setImageUrl(json.getString(Config.TAG_IMAGE_URL));
superHero.setProUrl(json.getString("pro_pic"));
Img =json.getString(Config.TAG_IMAGE_URL);
superHero.setName(json.getString(Config.TAG_NAME));
superHero.setRank(json.getInt(Config.TAG_RANK));
superHero.setstat(false);
Log.d("test",Img);
car.setImageUrl(Img);
} catch (JSONException e) {
e.printStackTrace();
}
listSuperHeroes.add(superHero);
}
loading=false;
adapter.notifyDataSetChanged();
//adapter.notifyItemInserted(listSuperHeroes.size());
我的猜测是，每次在 for循环中添加项目时，您都会刷新，这可能是您的问题。
答案 1 :(得分：0)
private int parseData(JSONArray array){
//temporary List to store all the new data from the json
List<SuperHeroes> tempList=new ArrayList<>();
//get start position to use later
int startPos=listSuperHeroes.size()-1;
for(int i = 0; i<array.length(); i++) {
SuperHeroes superHero = new SuperHeroes();
CardAdapter car = new CardAdapter();
JSONObject json = null;
try {
json = array.getJSONObject(i);
superHero.setImageUrl(json.getString(Config.TAG_IMAGE_URL));
superHero.setProUrl(json.getString("pro_pic"));
Img =json.getString(Config.TAG_IMAGE_URL);
superHero.setName(json.getString(Config.TAG_NAME));
superHero.setRank(json.getInt(Config.TAG_RANK));
superHero.setstat(false);
Log.d("test",Img);
car.setImageUrl(Img);
} catch (JSONException e) {
e.printStackTrace();
//You do not want to add the item incase there is a json exception
continue;
}
tempList.add(superHero);
// adapter.notifyDataSetChanged();
loading=false;
}
listSuperHeroes.addAll(tempList)
adapter.notifyItemRangeInserted(startPos,tempList.size());
}
您想要添加所有项目并致电notifyDatasetChanged()一次。如果您在每次添加时都致电notifyDatasetChanged()，您很可能会很快遇到Inconsistency Detected例外。
RecyclerView有几种辅助方法来通知数据集中的更改。
notifyDatasetChanged()是刷新整个数据集的那个，在你的场景中这将是一种过度杀伤。
考虑使用notifyItemRangeInserted等其他方法，这些方法会将项目添加到列表底部。
这有两个主要优点
- 您的列表不会跳转到添加数据的位置
- RecyclerView自动动画添加（可以覆盖）
如果您的职位/项目数不正确，您将面临Inconsistency Detected错误的问题。
在这种情况下，您可以使用notifyDatasetChanged()。
答案 2 :(得分：0)
试试这个，
private int previousTotal = 0;
private boolean loading = true;
private int visibleThreshold = 5;
int firstVisibleItem, visibleItemCount, totalItemCount;
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = mRecyclerView.getChildCount();
totalItemCount = mLayoutManager.getItemCount();
firstVisibleItem = mLayoutManager.findFirstVisibleItemPosition();
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
}
}
if (!loading && (totalItemCount - visibleItemCount)
<= (firstVisibleItem + visibleThreshold)) {
// End has been reached
Log.i("Yaeye!", "end called");
// Do something
loading = true;
}
}
});
LinearLayoutManager mLayoutManager;
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);