java-RecyclerView最初不加载数据
作者：互联网
我在Android项目的Fragment中使用了Spinner和RecyclerView.
直到我在微调器中选择一个项目,我的RecyclerView才会显示任何数据.
在不从微调器中选择项目的情况下,我该怎么做才能显示RecyclerView的结果？
在第一个回收站应该显示10个吸引力.
我的代码：
Attraction.java
package com.rayantec.reservation.reservationdemo.Model;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
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.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import com.android.volley.DefaultRetryPolicy;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import com.rayantec.reservation.reservationdemo.Adapter.AttractionAdapter;
import com.rayantec.reservation.reservationdemo.G;
import com.rayantec.reservation.reservationdemo.Lists.AttractionList;
import com.rayantec.reservation.reservationdemo.Lists.CityList;
import com.rayantec.reservation.reservationdemo.R;
import com.toptoche.searchablespinnerlibrary.SearchableSpinner;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
public class Attractions extends Fragment {
RecyclerView recyclerView;
ArrayList<AttractionList> AttractionData = new ArrayList<>();
public SearchableSpinner spinnerCitiest;
ArrayList<CityList> cityLists = new ArrayList<>();
ProgressDialog progressDialog;
public void showCity(View view) {
spinnerCitiest = (SearchableSpinner) view.findViewById(R.id.SpinnerCitiestId);
spinnerCitiest.setTitle("Please Select City");
spinnerCitiest.setPositiveButton("Ok");
//spinnerCitiest.setSelection(2);
JsonArrayRequest JsonObjectRequest = new JsonArrayRequest(Request.Method.GET, G.serverURL + "/android/jsyncs/getdata/city", null, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
//progressDialog.dismiss();
try {
for (int i = 0; i < response.length(); i++) {
JSONObject jsonOBJ = response.getJSONObject(i);
String id = jsonOBJ.getString("id");
String title = jsonOBJ.getString("title");
cityLists.add(new CityList(id, title));
}
} catch (JSONException e1) {
e1.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void one rrorResponse(VolleyError error) {
//progressDialog.dismiss();
Toast.makeText(G.context, "Server Connection error", Toast.LENGTH_SHORT).show();
}
});
JsonObjectRequest.setRetryPolicy(new DefaultRetryPolicy(7000, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
RequestQueue requestQueue = Volley.newRequestQueue(G.context);
requestQueue.add(JsonObjectRequest);
ArrayAdapter<CityList> adapterCities = new ArrayAdapter<CityList>(G.context, android.R.layout.simple_spinner_item, cityLists);
adapterCities.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerCitiest.setAdapter(adapterCities);
spinnerCitiest.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int position, long l) {
CityList cityList = (CityList) adapterView.getSelectedItem();
Toast.makeText(G.context, "City ID: " + cityList.getId() + ", City Name : " + cityList.getTitle(), Toast.LENGTH_SHORT).show();
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
});
}
public void showRandomAttractions(View view) {
recyclerView = (RecyclerView) view.findViewById(R.id.RecyclerAttracionId);
JsonArrayRequest JsonObjectRequests = new JsonArrayRequest(Request.Method.GET, G.serverURL + "/android/jsyncs/getdata/randattraction", null, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
progressDialog.dismiss();
//AttractionList sampledata = new AttractionList();
try {
for (int i = 0; i < response.length(); i++) {
JSONObject jsonOBJs = response.getJSONObject(i);
String id = jsonOBJs.getString("id");
String title = jsonOBJs.getString("title");
String imageUrl = jsonOBJs.getString("imageUrl");
String location = jsonOBJs.getString("location");
String type = jsonOBJs.getString("type");
String body = jsonOBJs.getString("body");
AttractionData.add(new AttractionList(id, title, body, location, imageUrl, type));
}
} catch (JSONException e1) {
e1.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void one rrorResponse(VolleyError error) {
progressDialog.dismiss();
Toast.makeText(G.context, "Server Connection error", Toast.LENGTH_SHORT).show();
}
});
JsonObjectRequests.setRetryPolicy(new DefaultRetryPolicy(7000, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
RequestQueue requestQueue = Volley.newRequestQueue(G.context);
requestQueue.add(JsonObjectRequests);
recyclerView.setLayoutManager(new LinearLayoutManager(G.context, LinearLayoutManager.VERTICAL, false));
AttractionAdapter attractionAdapter = new AttractionAdapter(AttractionData);
recyclerView.setAdapter(attractionAdapter);
}
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.attraction, container, false);
progressDialog = new ProgressDialog(getActivity());
progressDialog.setMessage("Please wait ...");
progressDialog.setCancelable(false);
progressDialog.show();
showCity(view);
showRandomAttractions(view);
return view;
}
}Attraction.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.CardView
android:id="@+id/cardviewattraction"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_marginStart="8dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
android:padding="3dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<com.toptoche.searchablespinnerlibrary.SearchableSpinner
android:id="@+id/SpinnerCitiestId"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:padding="3dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
</android.support.v7.widget.CardView>
<android.support.v7.widget.RecyclerView
android:id="@+id/RecyclerAttracionId"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/cardviewattraction"
tools:ignore="MissingConstraints" />
</android.support.constraint.ConstraintLayout>吸引力适配器
package com.rayantec.reservation.reservationdemo.Adapter;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import com.rayantec.reservation.reservationdemo.Lists.AttractionList;
import com.rayantec.reservation.reservationdemo.R;
import com.squareup.picasso.Picasso;
import java.util.ArrayList;
public class AttractionAdapter extends RecyclerView.Adapter<AttractionAdapter.AttractionViewHolder> {
ArrayList<AttractionList> attractionArrayList;
public AttractionAdapter(ArrayList<AttractionList> attractions) {
attractionArrayList = new ArrayList<>();
attractionArrayList = attractions;
}
@NonNull
@Override
public AttractionViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_attraction, parent, false);
return new AttractionViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull AttractionViewHolder holder, int position) {
AttractionList dataModel = attractionArrayList.get(position);
holder.txtTitle.setText(dataModel.getTitle());
holder.txtBody.setText(dataModel.getBody());
holder.txtType.setText(dataModel.getType());
holder.txtLocation.setText(dataModel.getLocation());
Picasso.get().load(dataModel.getImgUrl()).resize(130, 100).centerCrop().into(holder.imgAttraction);
}
@Override
public int getItemCount() {
return attractionArrayList.size();
}
public class AttractionViewHolder extends RecyclerView.ViewHolder{
public ImageView imgAttraction;
public TextView txtTitle;
public TextView txtBody;
public TextView txtLocation;
public TextView txtType;
public AttractionViewHolder(View itemView) {
super(itemView);
imgAttraction = (ImageView)itemView.findViewById(R.id.img_recycler_attraction);
txtTitle = (TextView)itemView.findViewById(R.id.txt_recycler_attractionTitle);
txtBody = (TextView)itemView.findViewById(R.id.txt_recycler_attractionBody);
txtLocation = (TextView)itemView.findViewById(R.id.txt_recycler_attractionPositions);
txtType = (TextView)itemView.findViewById(R.id.txt_recycler_attractionType);
}
//
}
}AttractionList.java
package com.rayantec.reservation.reservationdemo.Lists;
public class AttractionList {
private String id;
private String title;
private String body;
private String location;
private String imgUrl;
public AttractionList(String id, String title, String body, String location, String imgUrl, String type) {
this.id = id;
this.title = title;
this.body = body;
this.location = location;
this.imgUrl = imgUrl;
this.type = type;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
private String type;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getBody() {
return body;
}
public void setBody(String body) {
this.body = body;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public String getImgUrl() {
return imgUrl;
}
public void setImgUrl(String imgUrl) {
this.imgUrl = imgUrl;
}
}解决方法:
您需要测试一些内容,是否检查过showRandomAttractions(View view)方法中是否收到onResponse回调？这将验证Get调用是否按预期工作.
如果您收到该onResponse调用,请在将数据添加到AttractionData ArrayList中后,尝试在for循环之后调用吸引力适配器.notifyDataSetChanged().它看起来像这样：
try {
for (int i = 0; i < response.length(); i++) {
JSONObject jsonOBJs = response.getJSONObject(i);
String id = jsonOBJs.getString("id");
String title = jsonOBJs.getString("title");
String imageUrl = jsonOBJs.getString("imageUrl");
String location = jsonOBJs.getString("location");
String type = jsonOBJs.getString("type");
String body = jsonOBJs.getString("body");
AttractionData.add(new AttractionList(id, title, body, location, imageUrl, type));
// Notify your adapter that its data has changed.
attractionAdapter.notifyDataSetChanged();
}
} catch (JSONException e1) {
e1.printStackTrace();
}
您可以查看此documentation,以获取有关notifyDataSetChanged如何工作的更多信息.
标签：android-recyclerview,android-studio,android-spinner,java,android 来源： https://codeday.me/bug/20191024/1923443.html