代码之家  ›  专栏  ›  技术社区  ›  Nischal

我的customAdapter for recycler视图不工作,我提供了以下代码。请帮我解决这个问题

  •  0
  • Nischal  · 技术社区  · 3 年前

    导致回收器视图不显示的问题是什么?

    主要活动。Java语言

    import androidx.appcompat.app.AppCompatActivity;
    import androidx.recyclerview.widget.LinearLayoutManager;
    import androidx.recyclerview.widget.RecyclerView;
    import android.app.ProgressDialog;
    import android.os.Bundle;
    import android.util.Log;
    import android.widget.Toast;
    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.JsonObjectRequest;
    import com.android.volley.toolbox.Volley;
    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;
    import java.util.ArrayList;
    import java.util.List;
    
    public class MainActivity extends AppCompatActivity {
        RecyclerView recyclerView;
        private ProgressDialog dialog;
        List<ModelRecycler> newslist;
        RequestQueue requestQueue;
        private static final String API_URL = "https://newsapi.in/newsapi/news.php?key=qEhn6RWpLRebtTmkOpQcr7CxDKRGHi&category=tamil_state";
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            recyclerView=findViewById(R.id.recyclerView);
            newslist = new ArrayList<>();
    
            requestQueue = Volley.newRequestQueue(this);
            JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, API_URL, null, new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    try{
                        JSONArray array = response.getJSONArray("News");
                        for(int i=0;i<array.length();i++){
                            JSONObject c = array.getJSONObject(i);
                            String image = c.getString("image");
                            Log.d("App", "Log : " + c.getString("image"));
                            String title = c.getString("title");
                            Log.d("App", "Log : " + c.getString("title"));
                            String description = c.getString("description");
                            Log.d("App", "Log : " + c.getString("description"));
                            String published_date = c.getString("published_date");
                            Log.d("App", "Log : " + c.getString("published_date"));
                            String url = c.getString("url");
                            Log.d("App", "Log : " + c.getString("url"));
    //                        Toast.makeText(MainActivity.this, "Log : " + c.getString("published_date"), Toast.LENGTH_SHORT).show();
                            ModelRecycler modelRecycler = new ModelRecycler(image,title,description,published_date,url);
                            newslist.add(modelRecycler);
                        }
                    }catch (JSONException e){
                        Log.d("Error", "Json parsing error: " + e.getMessage());
                    }
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    Toast.makeText(MainActivity.this, "Error Occured: " + error, Toast.LENGTH_SHORT).show();
                }
            });
            requestQueue.add(jsonObjectRequest);
    
            LinearLayoutManager l1 = new LinearLayoutManager(getApplicationContext());
            l1.setOrientation(LinearLayoutManager.VERTICAL);
            recyclerView.setLayoutManager(l1);
            MyAdapter myAdapter = new MyAdapter(this, newslist);
            recyclerView.setAdapter(myAdapter);
        }
    
    }
    

    MyAdapter。Java语言

    
    import android.content.Context;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.Adapter;
    import android.widget.ImageView;
    import android.widget.TextView;
    
    import androidx.annotation.NonNull;
    import androidx.recyclerview.widget.RecyclerView;
    
    import com.bumptech.glide.Glide;
    
    import java.util.List;
    
    public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
    
        private Context mContext;
        private List<ModelRecycler> mData;
    
        public MyAdapter (Context mContext, List<ModelRecycler> mData) {
            this.mContext = mContext;
            this.mData = mData;
        }
    
        @NonNull
        @Override
        public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View v;
            LayoutInflater inflater = LayoutInflater.from(mContext);
            v = inflater.inflate(R.layout.list_item, parent, false);
            return new MyViewHolder(v);
        }
    
        @Override
        public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
            holder.news_title.setText(mData.get(position).getTitle());
            holder.news_description.setText(mData.get(position).getDescription());
            holder.news_time.setText(mData.get(position).getTime());
            Glide.with(mContext)
                    .load(mData.get(position).getImage())
                    .into(holder.news_image);
        }
    
        @Override
        public int getItemCount() {
            return mData.size();
        }
    
        public static class MyViewHolder extends RecyclerView.ViewHolder {
    
            TextView news_title, news_description, news_time;
            ImageView news_image;
    
            public MyViewHolder(@NonNull View itemView) {
                super(itemView);
                news_title = itemView.findViewById(R.id.news_title);
                news_description = itemView.findViewById(R.id.news_description);
                news_time = itemView.findViewById(R.id.news_time);
                news_image = itemView.findViewById(R.id.news_image);
            }
        }
    
    }
    

    ModelRecycler。Java语言

    
    public class ModelRecycler {
        String image, title, description, time, url;
        public ModelRecycler(String image, String title, String description, String time, String url) {
            this.image = image;
            this.title = title;
            this.description = description;
            this.time = time;
            this.url = url;
        }
    
        public ModelRecycler() {
    
        }
    
        public String getImage() {
            return image;
        }
    
        public String getTitle() {
            return title;
        }
    
        public String getDescription() {
            return description;
        }
    
        public String getTime() {
            return time;
        }
    
        public String getUrl() {
            return url;
        }
    
    }
    

    显示

    <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.technoapps.tamilnews">
        <uses-permission android:name="android.permission.INTERNET"/>
        <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
        <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
        <uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE"/>
        <uses-permission android:name="android.permission.WAKE_LOCK" />
        <application
            android:allowBackup="true"
            android:icon="@mipmap/ic_launcher"
            android:label="@string/app_name"
            android:roundIcon="@mipmap/ic_launcher_round"
            android:supportsRtl="true"
            android:theme="@style/Theme.TamilNews">
            <activity
                android:name=".MainActivity"
                android:exported="true">
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />
    
                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
        </application>
    
    </manifest>
    

    list\u布局

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:background="#F8FFFFFF">
    
        <ScrollView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:padding="4dp">
    
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical">
    
                <RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="190dp"
                    android:background="#fff"
                    android:elevation="8dp"
                    android:padding="10dp">
    
                    <TextView
                        android:id="@+id/news_title"
                        android:layout_width="240dp"
                        android:layout_height="wrap_content"
                        android:text="Lorem Ipsum Dolor Amet, Consectetur Adipiscing Elit Ipsum Dolor Amet"
                        android:textSize="18sp"
                        android:textStyle="bold" />
    
                    <TextView
                        android:id="@+id/news_description"
                        android:layout_width="240dp"
                        android:layout_height="wrap_content"
                        android:layout_below="@+id/news_title"
                        android:layout_marginTop="10dp"
                        android:text="There are many variations of passages of Lorem Ipsum available, but the majority have suffered alteration in some form..."
                        android:textSize="14dp" />
    
                    <TextView
                        android:id="@+id/news_time"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_below="@+id/news_description"
                        android:layout_marginTop="10dp"
                        android:text="30 min ago"
                        android:textSize="12dp"
                        android:textStyle="bold" />
    
                    <ImageView
                        android:id="@+id/news_image"
                        android:layout_width="wrap_content"
                        android:layout_height="150dp"
                        android:layout_marginLeft="5dp"
                        android:layout_toRightOf="@+id/news_title"
                        android:scaleType="centerCrop"
                        android:src="@drawable/search" />
    
                </RelativeLayout>
    
            </LinearLayout>
    
        </ScrollView>
    </LinearLayout>
    

    我从json获取数据,并尝试在回收器视图中显示。日志显示我正在获取数据,但未显示recycler视图。

    我如何解决这个问题?

    0 回复  |  直到 3 年前
        1
  •  0
  •   Sumit Kumar    3 年前

    请使用以下代码,

    public class MainActivity extends AppCompatActivity {
        RecyclerView recyclerView;
        private ProgressDialog dialog;
        List<ModelRecycler> newslist;
        RequestQueue requestQueue;
        private static final String API_URL = "https://newsapi.in/newsapi/news.php?key=qEhn6RWpLRebtTmkOpQcr7CxDKRGHi&category=tamil_state";
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            recyclerView=findViewById(R.id.recyclerView);
            newslist = new ArrayList<>();
    
            requestQueue = Volley.newRequestQueue(this);
            JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, API_URL, null, new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    try{
                        JSONArray array = response.getJSONArray("News");
                        for(int i=0;i<array.length();i++){
                            JSONObject c = array.getJSONObject(i);
                            String image = c.getString("image");
                            Log.d("App", "Log : " + c.getString("image"));
                            String title = c.getString("title");
                            Log.d("App", "Log : " + c.getString("title"));
                            String description = c.getString("description");
                            Log.d("App", "Log : " + c.getString("description"));
                            String published_date = c.getString("published_date");
                            Log.d("App", "Log : " + c.getString("published_date"));
                            String url = c.getString("url");
                            Log.d("App", "Log : " + c.getString("url"));
    //                        Toast.makeText(MainActivity.this, "Log : " + c.getString("published_date"), Toast.LENGTH_SHORT).show();
                            ModelRecycler modelRecycler = new ModelRecycler(image,title,description,published_date,url);
                            newslist.add(modelRecycler);
    
     LinearLayoutManager l1 = new LinearLayoutManager(getApplicationContext());
            l1.setOrientation(LinearLayoutManager.VERTICAL);
            recyclerView.setLayoutManager(l1);
            MyAdapter myAdapter = new MyAdapter(this, newslist);
            recyclerView.setAdapter(myAdapter);
                        }
                    }catch (JSONException e){
                        Log.d("Error", "Json parsing error: " + e.getMessage());
                    }
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    Toast.makeText(MainActivity.this, "Error Occured: " + error, Toast.LENGTH_SHORT).show();
                }
            });
            requestQueue.add(jsonObjectRequest);
    
           
        }
    
    }