Question

无法使用改进在布局中附加适配器的问题来获取JSON数据。我在Manifest文件中提到了Internet权限，并在gradle中导入了所有必需的库。

我的日志：

E/RecyclerView: No adapter attached; skipping layout
 W/dalvikvm: VFY: unable to find class referenced in signature (Landroid/graphics/drawable/Icon;)
I/dalvikvm: Could not find method android.widget.ImageView.setImageIcon, referenced from method android.support.v7.widget.AppCompatImageView.setImageIcon
W/dalvikvm: VFY: unable to resolve virtual method 13331: Landroid/widget/ImageView;.setImageIcon (Landroid/graphics/drawable/Icon;)V
D/dalvikvm: VFY: replacing opcode 0x6f at 0x0000
**E/RecyclerView: No adapter attached; skipping layout**
**D/com.example.chintankotadia.apidemo.activity.MainActivity: onResponse:[com.example.chintankotadia.apidemo.model.Example@4221c8b8, com.example.chintankotadia.apidemo.model.Example@4221c920, com.example.chintankotadia.apidemo.model.Example@4221c940, com.example.chintankotadia.apidemo.model.Example@4221c988, com.example.chintankotadia.apidemo.model.Example@4221c9e8, com.example.chintankotadia.apidemo.model.Example@4221ca08, com.example.chintankotadia.apidemo.model.Example@4221ca68, com.example.chintankotadia.apidemo.model.Example@4221ca88, com.example.chintankotadia.apidemo.model.Example@4221caa8, com.example.chintankotadia.apidemo.model.Example@4221cb30, com.example.chintankotadia.apidemo.model.Example@4221ccb0, com.example.chintankotadia.apidemo.model.Example@4221ccd0, com.example.chintankotadia.apidemo.model.Example@4221cd70, com.example.chintankotadia.apidemo.model.Example@4221cd90, com.example.chintankotadia.apidemo.model.Example@4221cdb0, com.example.chintankotadia.apidemo.model.Example@4221d690, com.example.chintankotadia.apidemo.model.Example@422**
**E/RecyclerView: No layout manager attached; skipping layout**
D/dalvikvm: GC_CONCURRENT freed 292K, 11% free 7902K/8839K, paused 3ms+2ms, total 37ms
W/IInputConnectionWrapper: getSelectedText on inactive InputConnection
W/IInputConnectionWrapper: setComposingText on inactive InputConnection
W/IInputConnectionWrapper: getExtractedText on inactive InputConnection

我的代码：

MainActivity.java

 public class MainActivity extends AppCompatActivity {

   private static final String TAG = MainActivity.class.getName();
            private List<Example> list;
            private RecyclerView recyclerView;
            private MainAdapter adapter;

            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);
                recyclerView = findViewById(R.id.rv_demo);
                list = new ArrayList<>();
                loadResponse();
            }

            private void loadResponse() {

            Retrofit retrofit = new Retrofit.Builder()
                 .baseUrl("http://jsonplaceholder.typicode.com")    
                 .addConverterFactory(GsonConverterFactory.create())
                 .build();
            ReqInterface request = 
                 retrofit.create(ReqInterface.class);

            Call<List<Example>> call = request.getMyJSON();

            call.enqueue(new Callback<List<Example>>() {

            @Override
            public void onResponse(Call<List<Example>> call, 
                       Response<List<Example>> response) {

            if (response.isSuccessful()) {


            List<Example> exampleList = response.body();
            Example example = null;

            for (int i = 0; i < exampleList.size(); i++) {

             example = new Example();
             String userid = 
             String.valueOf(exampleList.get(i).getUserId());
             String title = exampleList.get(i).getTitle();
             String body = exampleList.get(i).getBody();                   
             example.setUserId(Integer.valueOf(userid));
             example.setTitle(title);
             example.setBody(body);
             list.add(example);
        }
        Log.d(TAG, "onResponse:" + list);
        adapter = new MainAdapter(MainActivity.this, list);
        recyclerView.setAdapter(adapter);
        adapter.notifyDataSetChanged();
       } else {
         try {

       JSONObject jObjError = new 
            JSONObject(response.errorBody().string());
       Toast.makeText(MainActivity.this, 
       jObjError.getString("message"), Toast.LENGTH_LONG).show();

      } catch (Exception e) {
       Toast.makeText(MainActivity.this, e.getMessage(), 
           Toast.LENGTH_LONG).show();
         }
       }
      }

      @Override
        public void onFailure(Call<List<Example>> call, Throwable t) 
        {
           Toast.makeText(MainActivity.this, "Error in fetching 
            data", Toast.LENGTH_SHORT).show();
                    }
                });
            }
   }

MainAdapter.java

  public class MainAdapter extends RecyclerView.Adapter<MainAdapter.MyViewHolder> {

                private List<Example> list;
                private Context context;

                public MainAdapter(MainActivity context, List<Example> list) {
                    this.context = context;
                    this.list = list;
                }

                @Override
                public MyViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
                    View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.card_main, viewGroup, false);
                    return new MyViewHolder(view);
                }

                @Override
                public void onBindViewHolder(MyViewHolder holder, int position) {

                    Example example = list.get(position);

                    holder.userId.setText(example.getUserId());
                    holder.title.setText(example.getTitle());
                    holder.body.setText(example.getBody());
                }

                @Override
                public int getItemCount() {
                    return list.size();
                }

                public class MyViewHolder extends RecyclerView.ViewHolder {
                    TextView userId, title, body;

                    public MyViewHolder(View itemView) {
                        super(itemView);

                        userId = itemView.findViewById(R.id.tv_userid_no);
                        title = itemView.findViewById(R.id.tv_title_text);
                        body = itemView.findViewById(R.id.tv_body_text);
                    }
                }
            }

ReqInterface.java

   public interface ReqInterface {

@GET("/posts")
Call<List<Example>> getMyJSON();
}

我的模型类 Example.java

 public class Example {

@SerializedName("userId")
@Expose
private Integer userId;
@SerializedName("id")
@Expose
private Integer id;
@SerializedName("title")
@Expose
private String title;
@SerializedName("body")
@Expose
private String body;

public Integer getUserId() {
    return userId;
}

public void setUserId(Integer userId) {
    this.userId = userId;
}

public Integer getId() {
    return id;
}

public void setId(Integer 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;
}
}

Answer 1

您需要向LayoutManager添加RecyclerView。

尝试添加此内容：

recyclerView.setLayoutManager(new LinearLayoutManager(this));

仅供参考我们可以使用LayoutManager个LinearLayoutManager，而不只是<form method="post" class="form-horizontal" action="test/user/add" id="submitForm"> ..... </form>。

Answer 2

You have to add Layout Manager to your RecyclerView From xml

<android.support.v7.widget.RecyclerView
    xmlns:app="http://schemas.android.com/apk/res-auto"
    app:layoutManager="android.support.v7.widget.LinearLayoutManager" >

From code

LinearLayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
mRecyclerView.setLayoutManager(mLayoutManager);

Answer 3

In onCreate() of your activity,

recyclerView = findViewById(R.id.rv_demo);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setHasFixedSize(true);

无法在Retrofit中获得响应并获得No layout manager附加跳过布局的错误

3 个答案: