问题
I am new to recycler view widget , i want to get my data from my api url and list the data into my recycler view , i have these classes : recyclerAdapter , recyclerView , MainActivity , row .
the data is loaded from api succesfully but the does not set the json string received from the api in the recycler view , and the recycler view is shown white and empty . any body can find the problem in my code ?
MainActivity.java code is :
public class MainActivity extends AppCompatActivity {
final String member_id = "2";
final String get_cash_url = "http://famila1.ir/khabgah/get_khabgah_cash.php?member_id=" + member_id;
private RecyclerView rc;
private RecyclerView.Adapter adapter;
private List<recyclerView> cashList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
rc = findViewById(R.id.rc);
rc.setHasFixedSize(true);
rc.setLayoutManager(new LinearLayoutManager(this));
cashList = new ArrayList<>();
loadUrlData();
}
private void loadUrlData() {
final ProgressDialog progressDialog = new ProgressDialog(this);
progressDialog.setMessage("Loading...");
progressDialog.show();
StringRequest stringRequest = new StringRequest(Request.Method.GET,
get_cash_url, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
System.out.println(response);
progressDialog.dismiss();
try {
JSONObject jsonObject = new JSONObject(response);
JSONArray array = jsonObject.getJSONArray("bedehkariHa");
for (int i = 0; i < array.length(); i++) {
JSONObject jo = array.getJSONObject(i);
recyclerView temp = new recyclerView(jo.getString("hazine"), jo.getString("tarikh"), jo.getString("tozihat"), jo.getString("member_id"), "kir");
cashList.add(temp);
}
adapter = new recyclerAdapter(cashList, getApplicationContext());
rc.setAdapter(adapter);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
progressDialog.dismiss();
progressDialog.setMessage("somthing was wrong during runnig app...");
progressDialog.show();
System.out.println("error: "+error);
}
}
);
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(stringRequest);
}
}
recyclerView.java code is :
public class recyclerView {
private String hazine,tarikh,tozihat,madarkharj,harSahm;
public recyclerView(String hazine,String tarikh,String tozihat,String madarkharj,String harSahm ) {
this.hazine = hazine;
this.harSahm = harSahm;
this.madarkharj = madarkharj;
this.tarikh = tarikh;
this.tozihat = tozihat;
}
public String getHazine(){return hazine;}
public String getTarikh(){return tarikh;}
public String getTozihat(){return tozihat;}
public String getMadarkharj(){return madarkharj;}
public String getHarSahm(){return harSahm;}
}
public class recyclerAdapter extends RecyclerView.Adapter<recyclerAdapter.ViewHolder>{
public static final String KEY_NAME = "name";
public static final String KEY_LASTNAME = "lastname";
public static final String KEY_IMAGE = "image";
public static final String KEY_HAZINE = "hazine";
public static final String KEY_TARIKH = "date";
public static final String KEY_MADARKHARJ = "member_id";
private List<recyclerView> cashlist;
private Context context;
Recycler adapter class is this :
public recyclerAdapter(List<recyclerView> cashlist, Context context){
this.cashlist = cashlist;
this.context = context;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View v = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.row,viewGroup,false);
return new recyclerAdapter.ViewHolder(v);
}
@Override
public void onBindViewHolder(@NonNull ViewHolder viewHolder, final int position) {
final recyclerView recyclerviews = cashlist.get(position);
viewHolder.hazine.setText(recyclerviews.getHazine());
viewHolder.harSahm.setText(recyclerviews.getHarSahm());
viewHolder.tarikh.setText(recyclerviews.getTarikh());
viewHolder.tozihat.setText(recyclerviews.getTozihat());
viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(context, "TEST is Toasted", Toast.LENGTH_SHORT).show();
}
});
}
@Override
public int getItemCount() {
return cashlist.size();
}
// Inside this class, we’ll have another class for the ViewHolder thus
public class ViewHolder extends RecyclerView.ViewHolder{
TextView hazine,harSahm,tozihat,tarikh;
public ViewHolder(@NonNull View itemView) {
super(itemView);
hazine = (TextView) itemView.findViewById(R.id.mablaq_hazine);
harSahm = (TextView) itemView.findViewById(R.id.bedehkariha_dong);
tarikh = (TextView) itemView.findViewById(R.id.tarikh_hazine);
tozihat = (TextView) itemView.findViewById(R.id.babate_hazine);
}
}
}
and this is row.xml :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" android:background="@android:color/white" >
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content" android:padding="5dp"
android:background="@android:color/holo_blue_bright" android:layout_marginBottom="5dp"
>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent" android:padding="3dp"
android:background="@android:color/holo_blue_dark">
<TextView
android:text="سهم شما:"
android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="@+id/tarikh_hazine2"
android:textSize="18sp" android:textColor="@android:color/holo_red_dark"
android:textStyle="bold"
/>
<TextView
android:text="قالب پرداخت"
android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="@+id/bedehkariha_dong"
android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"/>
<TextView
android:text="مبلغ کل: "
android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="@+id/mablaq_hazine2"
android:textSize="18sp" android:textColor="@android:color/holo_red_dark"
android:textStyle="bold"/>
<TextView
android:text="مبلغ کل"
android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="@+id/mablaq_hazine" android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"/>
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent" android:padding="3dp"
android:background="@android:color/holo_blue_dark">
<TextView
android:text="تاریخ:"
android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="@+id/tarikh_hazine22"
android:textSize="18sp" android:textColor="@android:color/holo_red_dark"
android:textStyle="bold"
/>
<TextView
android:text="تاریخ"
android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="@+id/tarikh_hazine" android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:inputType="textMultiLine"
/>
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent" android:padding="3dp"
android:background="@android:color/holo_blue_dark">
<TextView
android:text="توضیحات: "
android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="@+id/babate_hazine2"
android:textSize="18sp" android:textColor="@android:color/holo_red_dark"
android:textStyle="bold"
/>
<TextView
android:text="هزینه بابت......"
android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="@+id/babate_hazine" android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:inputType="textMultiLine"
android:gravity="right"/>
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_marginTop="2dp">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_weight="1" android:padding="2dp">
<TextView
android:text="پرداخت از: "
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/pardakhtaz" android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none"
android:background="@android:color/white" android:gravity="center"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/pardakhtaz1" android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="#FF75AD06" android:padding="2dp"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/pardakhtaz2" android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="@android:color/holo_green_dark" android:padding="2dp"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/pardakhtaz3" android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="#FF75AD06" android:padding="2dp"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/pardakhtaz4" android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="@android:color/holo_green_dark" android:padding="2dp"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/pardakhtaz5" android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="#75ad06" android:padding="2dp"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/pardakhtaz6" android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="@android:color/holo_green_dark" android:padding="2dp"
/>
</LinearLayout>
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_weight="1" android:padding="2dp">
<TextView
android:text="هزینه شریکی با:"
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/moshtarak_ba"
android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none"
android:background="@android:color/white" android:gravity="center"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/moshtarak_ba1"
android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="#FFF10D0D" android:padding="2dp"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/moshtarak_ba2"
android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="@android:color/holo_red_dark" android:padding="2dp"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/moshtarak_ba3"
android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="#FFF10D0D" android:padding="2dp"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/moshtarak_ba4"
android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="@android:color/holo_red_dark" android:padding="2dp"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/moshtarak_ba5"
android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="#FFF10D0D" android:padding="2dp"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content" android:id="@+id/moshtarak_ba6"
android:layout_weight="1"
android:textSize="18sp" android:textColor="@android:color/black"
android:fadingEdge="none" android:gravity="right"
android:background="@android:color/holo_red_dark" android:padding="2dp"
/>
</LinearLayout>
</LinearLayout>
</LinearLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
回答1:
Parsing Problem first I got.Change
JSONArray array = jsonObject.getJSONArray("bedehkariHa");
To:
JSONArray array = jsonObject.getJSONArray("bedehkari_ha");
Then check
回答2:
According to the result from JSON, the key bedehkariHa does not exist and that may cause Parsing Error, a JSONException. So instead of this:
JSONArray array = jsonObject.getJSONArray("bedehkariHa");
use this to get the JSONArray associated with bedehkari_ha:
JSONArray array = jsonObject.getJSONArray("bedehkari_ha");
回答3:
I'd firstly look at your general approach. You seem to be instantiating a Volley request...I bet this isn't the only one in your app?
Make a "NetworkService" singleton that holds application Context and call that as a service layer...rather than calling a new Volley instance for each class you need it!
Here is one I wrote for my apps...I have omitted a lot of the methods and left you with a GetRequest method. You could add the URLEncoding of parameters in the service.
You can call this by simply in an activity/fragment:
HashMap<String,String> urlParams = new HashMap<>();
urlParams.put("param1","value1");
VolleyRequestService.getInstance(this).getJSONObject(urlParams, true, new GetJSONObjectRequestable() {
@Override
public void onSuccessfulAPIResponse(JSONObject response) {
}
@Override
public void onFailedAPIResponse(VolleyRequestService.ErrorType errorType, String description) {
}
},"https://myendpoint.com/endpoint.php");
And the service:
package devdroidjonno.com.tests.Networking;
import android.content.Context;
import android.util.Log;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import java.util.HashMap;
import java.util.Map;
public class VolleyRequestService {
private static final String DEBUG = "VolleyRequestService";
private static final String authCode = "87fe987vwefb987eb9w87wv";
private static VolleyRequestService ourInstance = null;
private static RequestQueue requestQueue;
private VolleyRequestService(Context applicationContext) {
this.requestQueue = Volley.newRequestQueue(applicationContext);
Log.d(DEBUG, "Init Volley Service " + this.hashCode());
}
public static VolleyRequestService getInstance(Context context) {
if (ourInstance == null) {
ourInstance = new VolleyRequestService(context.getApplicationContext());
}
return ourInstance;
}
// A GET request to an endpoint that returns a JSONObject.
public void getJSONObject(HashMap<String, String> urlParams, final boolean requiresAuthHeader, final GetJSONObjectRequestable callback, String endpointURL) {
endpointURL += "?";
for (Map.Entry mapEntry : urlParams.entrySet()) {
endpointURL += mapEntry.getKey() + "=" + mapEntry.getValue() + "&";
}
Log.d(DEBUG, endpointURL);
requestQueue.add(new JsonObjectRequest(Request.Method.GET, endpointURL, null, response -> {
Log.d(DEBUG, response.toString());
try {
if (response.has("error")) {
callback.onFailedAPIResponse(ErrorType.APIERROR, response.getString("error"));
} else {
callback.onSuccessfulAPIResponse(response);
}
} catch (Exception e) {
callback.onFailedAPIResponse(ErrorType.EXCEPTION, e.getLocalizedMessage());
e.printStackTrace();
}
}, error -> callback.onFailedAPIResponse(ErrorType.VOLLEYERROR, error.getMessage())) {
@Override
public Map<String, String> getHeaders() {
HashMap<String, String> headers = new HashMap<>();
if (requiresAuthHeader) headers.put("Authorization", authCode);
return headers;
}
});
}
public enum ErrorType {
NOERROR, APIERROR, VOLLEYERROR, AUTHERROR, EXCEPTION
}
}
And finally the callback...
package devdroidjonno.com.tests.Networking;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
public interface GetJSONObjectRequestable {
void onSuccessfulAPIResponse(JSONObject response) throws JSONException, IOException;
void onFailedAPIResponse(VolleyRequestService.ErrorType errorType, String description);
}
来源：https://stackoverflow.com/questions/52840282/android-recycler-view-adapter