如何片段

我有一個片段應用RecycleView，名稱是galery。在片段Galery中，我將顯示一個包含名稱列表的recycleView。但我覺得在這個腳本錯誤：如何片段

LinearLayoutManager llm = new LinearLayoutManager(this);

，這我全碼：

public class galery extends Fragment { 
private RecyclerView lvhape; 
private RequestQueue requestQueue; 
private StringRequest stringRequest; 

ArrayList<HashMap<String, String>> list_data; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    View rootView = inflater.inflate(R.layout.fragment_galery, container, false); 
    String url = "http://bls.hol.es/read.php"; 

    lvhape = (RecyclerView) rootView.findViewById(R.id.lvhape); 
    LinearLayoutManager llm = new LinearLayoutManager(this); 
    llm.setOrientation(LinearLayoutManager.VERTICAL); 
    lvhape.setLayoutManager(llm); 

    requestQueue = Volley.newRequestQueue(galery.this); 
    list_data = new ArrayList<HashMap<String, String>>(); 

    stringRequest = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() { 
     @Override 
     public void onResponse(String response) { 
      Log.d("response", response); 
      try { 
       JSONObject jsonObject = new JSONObject(response); 
       JSONArray jsonArray = jsonObject.getJSONArray("result"); 
       for (int a = 0; a < jsonArray.length(); a++) { 
        JSONObject json = jsonArray.getJSONObject(a); 
        HashMap<String, String> map = new HashMap<String, String>(); 
        map.put("id", json.getString("id")); 
        map.put("nama", json.getString("nama")); 
        map.put("alamat", json.getString("alamat")); 
        map.put("poto", json.getString("poto")); 
        list_data.add(map); 
        AdapterList adapter = new AdapterList(galery.this, list_data); 
        lvhape.setAdapter(adapter); 

       } 
      } catch (JSONException e) { 
       e.printStackTrace(); 
      } 
     } 
    }, new Response.ErrorListener() { 
     @Override 
     public void onErrorResponse(VolleyError error) { 
      Toast.makeText(getActivity().getApplicationContext(), error.getMessage(), Toast.LENGTH_SHORT).show(); 
     } 
    }); 
    requestQueue.add(stringRequest); 
    return rootView; 
}

}

來源

2017-06-13 sate wedos

期間在片段'onCreate'尚未創建的視圖。因此你需要在你的'onCreateView'裏面膨脹它。 – Enzokie

檢查我的答案。 @iqbal –

galery.this將傳遞的片段的對象。該適配器需要一個上下文對象。傳遞getActivity（）。 –

試穿這個片段創建的.xml級適配器和模型類RecyclerView。

public class Event extends Fragment { 
    RecyclerView recyclerView; 
    private Event_Adapter event_adapter; 
    public Event_Model event_model; 
    public static List<Event_Model> list; 
    RecyclerView.LayoutManager mLayoutManager; 
    private static final String FETCH_ID = "id"; 
    private static final String FETCH_NAME = "event_type"; 
    private static final String FETCH_MOBILE = "contact"; 
    private static final String FETCH_DATE = "date"; 
    private static final String FETCH_IMAGE = "uri"; 
    public static final String FETCH_DETAIL = "Your Url"; 
    String type,number,date,uri,id; 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     View v= inflater.inflate(R.layout.fragment_event, container, false); 

     list = new ArrayList<Event_Model>(); 
     recyclerView = (RecyclerView) v.findViewById(R.id.event_recycler); 
     mLayoutManager = new LinearLayoutManager(getActivity()); 
     recyclerView.setLayoutManager(mLayoutManager); 
     fetchdetails(); 

     return v; 
    } 
    private void fetchdetails(){ 
     StringRequest jor = new StringRequest(Request.Method.POST, FETCH_DETAIL, 
       new Response.Listener<String>() { 
        @Override 
        public void onResponse(String response) { 
       /*  Toast.makeText(getActivity(),response,Toast.LENGTH_LONG).show();*/ 

         try { 
          JSONArray ja = new JSONArray(response); 
          for (int i = 0; i < ja.length(); i++) { 

           JSONObject jsonObject = ja.getJSONObject(i); 


       Integer.parseInt(jsonObject.optString("id").toString()); 
           type =  jsonObject.getString(FETCH_NAME); 
           number = jsonObject.getString(FETCH_MOBILE); 
           date = jsonObject.getString(FETCH_DATE); 
           uri = jsonObject.getString(FETCH_IMAGE); 
           id =  jsonObject.getString(FETCH_ID); 
        event_model = new Event_Model(type,number,date,uri,id); 
           list.add(event_model); 
          } 
         } catch (JSONException e) { 
          e.printStackTrace(); 
         } 
         event_adapter= new Event_Adapter(getActivity(), list); 
         recyclerView.setAdapter(event_adapter); 
        } 
       }, 
       new Response.ErrorListener() { 
        @Override 
        public void onErrorResponse(VolleyError error) { 


         Log.e("Volley", "Error"); 

        } 
       } 

     ); 
     RetryPolicy retryPolicy=new DefaultRetryPolicy(60000,0,DefaultRetryPolicy.DEFAULT_BACKOFF_MULT); 
     jor.setRetryPolicy(retryPolicy); 
     VolleySingleton.getInstance(getActivity()).addToRequestQueue(jor); 
    } 

}

來源

2017-06-13 05:16:59

onCreate()將前onCreateView()方法來調用，所以getView()將返回null 嘗試這樣

public class galery extends Fragment { 
private RecyclerView lvhape; 
private RequestQueue requestQueue; 
private StringRequest stringRequest; 

ArrayList<HashMap<String, String>> list_data; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

} 
@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    View rootView = inflater.inflate(R.layout.fragment_galery, container, false); 

    return rootView; 
} 


public void onViewCreated(View view, Bundle savedInstanceState) { 
    String url = "http://bls.hol.es/read.php"; 

    lvhape = (RecyclerView) view.findViewById(R.id.lvhape); 
    LinearLayoutManager llm = new LinearLayoutManager(this); 
    llm.setOrientation(LinearLayoutManager.VERTICAL); 
    lvhape.setLayoutManager(llm); 

    requestQueue = Volley.newRequestQueue(getActivity()); 
    list_data = new ArrayList<HashMap<String, String>>(); 

    stringRequest = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() { 
     @Override 
     public void onResponse(String response) { 
      Log.d("response", response); 
      try { 
       JSONObject jsonObject = new JSONObject(response); 
       JSONArray jsonArray = jsonObject.getJSONArray("result"); 
       for (int a = 0; a < jsonArray.length(); a++) { 
        JSONObject json = jsonArray.getJSONObject(a); 
        HashMap<String, String> map = new HashMap<String, String>(); 
        map.put("id", json.getString("id")); 
        map.put("nama", json.getString("nama")); 
        map.put("alamat", json.getString("alamat")); 
        map.put("poto", json.getString("poto")); 
        list_data.add(map); 
        AdapterList adapter = new AdapterList(galery.this, list_data); 
        lvhape.setAdapter(adapter); 

       } 
      } catch (JSONException e) { 
       e.printStackTrace(); 
      } 
     } 
    }, new Response.ErrorListener() { 
     @Override 
     public void onErrorResponse(VolleyError error) { 
      Toast.makeText(getActivity().getApplicationContext(), error.getMessage(), Toast.LENGTH_SHORT).show(); 
     } 
    }); 
    requestQueue.add(stringRequest); 
}

來源

2017-06-13 04:19:27

我已經完成了你的建議。但是，這仍然是一個錯誤：錯誤：（23，24）錯誤：不兼容的類型：galery不能轉換到上下文我不知道該怎麼辦 –

我已經更新代碼，請 –

OKE。我仍然會檢查這個 –

試試這個

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
} 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
View rootView = inflater.inflate(R.layout.fragment_galery, container, false); 

String url = "http://bls.hol.es/read.php"; 

lvhape = (RecyclerView) getView().findViewById(R.id.lvhape); 
LinearLayoutManager llm = new LinearLayoutManager(gallary.getContext()); 
llm.setOrientation(LinearLayoutManager.VERTICAL); 
lvhape.setLayoutManager(llm); 

requestQueue = Volley.newRequestQueue(galery.this); 
list_data = new ArrayList<HashMap<String, String>>(); 

stringRequest = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() { 
    @Override 
    public void onResponse(String response) { 
     Log.d("response", response); 
     try { 
      JSONObject jsonObject = new JSONObject(response); 
      JSONArray jsonArray = jsonObject.getJSONArray("result"); 
      for (int a = 0; a < jsonArray.length(); a++) { 
       JSONObject json = jsonArray.getJSONObject(a); 
       HashMap<String, String> map = new HashMap<String, String>(); 
       map.put("id", json.getString("id")); 
       map.put("nama", json.getString("nama")); 
       map.put("alamat", json.getString("alamat")); 
       map.put("poto", json.getString("poto")); 
       list_data.add(map); 
       AdapterList adapter = new AdapterList(galery.this, list_data); 
       lvhape.setAdapter(adapter); 

      } 
     } catch (JSONException e) { 
      e.printStackTrace(); 
     } 
    } 
}, new Response.ErrorListener() { 
    @Override 
    public void onErrorResponse(VolleyError error) { 
     Toast.makeText(getActivity().getApplicationContext(), error.getMessage(), Toast.LENGTH_SHORT).show(); 
    } 
}); 
requestQueue.add(stringRequest); 

return rootView; 
}

來源

2017-06-13 04:25:28

上相同的錯誤：galery不能轉換到Contect –

@Iqbal嘗試這種RecyclerView.LayoutManager的layoutManager =新LinearLayoutManager（galery.getContext（））; –

並且請粘貼錯誤 –

我做了一些改變，它在我的應用程序正常工作嘗試它，如果發生任何錯誤發表評論。

public class GalaryFragment extends Fragment { 
private RecyclerView recyclerView; 
private List<ProductModel> list1; 
private ProductModel productMode; 
private ProductAdapter productAdapter; 

@Nullable 
@Override 
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 
    return inflater.inflate(R.layout.frament_galary, container, false); 
} 
@Override 
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { 
    super.onViewCreated(view, savedInstanceState); 
    String url = "http://bls.hol.es/read.php"; 
    mRecyclerView = (RecyclerView) view.findViewById(R.id.lvhape); 
    list1 = new ArrayList<>(); 
    mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity(), LinearLayoutManager.HORIZONTAL, false)); 
    cashbackAdapter = new ProductAdapter(getActivity(), list1); 
    mRecyclerView2.setAdapter(productAdapter); 
    final ProgressDialog dialog = new ProgressDialog(getActivity()); 
    dialog.setMessage("Loading......"); 
    dialog.show(); 
    StringRequest stringRequest = new StringRequest(Method.POST, url, new Response.Listener<String>() { 
       @Override 
       public void onResponse(String response) { 
        //Toast.makeText(getActivity(),response+"",Toast.LENGTH_LONG).show(); 
        try { 
         JSONArray jsonArray = new JSONArray(response); 
         for (int i = 0; i < jsonArray.length(); i++) { 
          JSONObject jsonObject = jsonArray.getJSONObject(i); 
          String id = jsonObject.getString("id"); 
          String name = jsonObject.getString("name"); 
          String image = jsonObject.getString("image"); 
          productModel = new ProductModel(id, name, image); 
          list1.add(productModel); 
         } 
         productAdapter.notifyDataSetChanged(); 
        } catch (JSONException e) { 
         e.printStackTrace(); 
        } 
       } 
      }, new Response.ErrorListener() { 
     @Override 
     public void onErrorResponse(VolleyError error) { 
      Log.e("Volley", "Error"); 
     } 
    }); 
    VolleySingleton.getInstance(getActivity()).addToRequestQueue(stringRequest); 
    } 
}

ProductAdapter代碼：

public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.MyViewHolder> { 
private List<ProductModel> list; 
private Context mContext; 

public ProductAdapter(Context mContext, List<ProductModel> list) { 
    this.mContext = mContext; 
    this.list=list; 
} 

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


@Override 
public void onBindViewHolder(MyViewHolder holder, int position) { 
    final ProductModel productModel=list.get(position); 
    holder.name.setText(productModel.getName()); 
    Picasso.with(mContext) 
      .load(productModel.getImage()) 
      .placeholder(R.mipmap.ic_launcher) 
      .error(R.mipmap.ic_launcher) 
      .into(holder.iv); 

} 

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

public class MyViewHolder extends RecyclerView.ViewHolder { 
    public TextView name; 
    public ImageView iv; 
    public MyViewHolder(View view) { 
     super(view); 
     name = (TextView) view.findViewById(R.id.name); 
     iv = (ImageView) view.findViewById(R.id.image); 
     } 
    } 
    }

PoductModel代碼：

public class ProductModel { 
    String id; 
    String name; 
    String image; 

public nameModel(String id, String name, String image) { 
    this.id = id; 
    this.name = name; 
    this.image = image; 
} 

public String getId() { 
    return id; 
} 

public void setId(String id) { 
    this.id = id; 
} 

public String getname() { 
    return name; 
} 

public void setname(String name) { 
    this.name = name; 
} 

public String getImage() { 
    return image; 
} 

public void setImage(String image) { 
    this.image = image; 
    } 
}

VolleySingleton類：

public class VolleySingleton { 
private static VolleySingleton mInstance; 
private RequestQueue mRequestQueue; 
private ImageLoader mImageLoader; 
private static Context mCtx; 

private VolleySingleton(Context context) { 
    mCtx = context; 
    mRequestQueue = getRequestQueue(); 

    mImageLoader = new ImageLoader(mRequestQueue, 
      new ImageLoader.ImageCache() { 
       private final LruCache<String, Bitmap> 
         cache = new LruCache<String, Bitmap>(20); 

       @Override 
       public Bitmap getBitmap(String url) { 
        return cache.get(url); 
       } 

       @Override 
       public void putBitmap(String url, Bitmap bitmap) { 
        cache.put(url, bitmap); 
       } 
      }); 
} 

public static synchronized VolleySingleton getInstance(Context context) { 
    if (mInstance == null) { 
     mInstance = new VolleySingleton(context); 
    } 
    return mInstance; 
} 

public RequestQueue getRequestQueue() { 
    if (mRequestQueue == null) { 
     // getApplicationContext() is key, it keeps you from leaking the 
     // Activity or BroadcastReceiver if someone passes one in. 
     mRequestQueue = Volley.newRequestQueue(mCtx.getApplicationContext()); 
    } 
    return mRequestQueue; 
} 

public <T> void addToRequestQueue(Request<T> req) { 
    getRequestQueue().add(req); 
} 

public ImageLoader getImageLoader() { 
    return mImageLoader; 
    } 
}

來源

2017-06-13 05:28:49

回答

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