Android RecyclerView適配器未初始化

起初對不起我的英文不好。我正在使用Android RecyclerView。從我的Activity向服務器發送數據請求，並通過調用onCreate方法中的sendRequestForHistory（）方法從服務器獲得響應。在調用sendRequestForHistory（）之後，初始化我的數據適配器，但在這裏我的ArrayList是空的。在sendRequestForHistory（）方法中，從服務器獲取數據並添加到ArrayList。我的代碼是這樣的。Android RecyclerView適配器未初始化

public class HistoryActivity extends AppCompatActivity { 
private Toolbar toolbar; 
private ProgressDialog PD; 
private RecyclerView recyclerView; 
private HistoryAdapter historyAdapter; 
private Boolean isInternetPresent = false; 
private ConnectionDetector cd; 
private TextView tvEmptyView; 
private ArrayList<ItemHistory> itemHistories; 
protected Handler handler; 
private LinearLayoutManager linearLayoutManager; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_history); 
    dbHelper= new DatabaseHelper(this); 
    handler = new Handler(); 
    itemHistories = new ArrayList<ItemHistory>(); 

    toolbar = (Toolbar) findViewById(R.id.tool_bar); 
    toolbar.setTitle(brandName); 
    setSupportActionBar(toolbar); 

    PD = new ProgressDialog(this); 
    PD.setMessage("Loading....."); 
    PD.setCancelable(false); 
    recyclerView = (RecyclerView)findViewById(R.id.recycler_view_history); 
    recyclerView.setHasFixedSize(true); 
    linearLayoutManager = new LinearLayoutManager(this); 
    recyclerView.setLayoutManager(linearLayoutManager); 

    sendRequestForHistory(); 

    // Here itemHistories is empty. 
    historyAdapter = new HistoryAdapter(itemHistories, recyclerView); 
    recyclerView.setAdapter(historyAdapter); 
    historyAdapter.notifyDataSetChanged(); 
    } 

private void sendRequestForHistory() { 
//send request to server and get response history data 
// then history dada add to itemHistories ArrayList 

itemHistories.add(new ItemHistory(requestReceiver[i], requestAmount[i],requestCost[i]); 

    } 
}

來源

2016-10-06 crazyCoder

可以顯示適配器代碼嗎？ –

@馬修希勒，謝謝我認爲適配器班是好的。當我使用'historyAdapter = new HistoryAdapter（itemHistories，recyclerView）; recyclerView.setAdapter（historyAdapter）; historyAdapter.notifyDataSetChanged（）; '在sendRequestForHistory（）它工作正常。 – crazyCoder

sendRequestForHistory（）以某種方式創建一個新線程？如果是這樣，那麼設置適配器需要等到這個完成。 –

我希望這會幫助你，你這是互聯網電話這就是爲什麼當響應接收，那麼你可以添加

private void sendRequestForHistory() { 
    ApiClient.getArticles(page, category_name, type).enqueue(new Callback<List<Article>>() { 
     @Override 
     public void onResponse(Call<List<Article>> call, Response<List<Article>> response) { 
      if(response.isSuccessfull()){ 
       for(Article article: response.body().getList()){ 
        historyAdapter.addItem(article); 
       } 
      }else{ 
       Toast.makeText(getContext(),response.message(),Toast.LENGTH_SHORT).show(); 
      } 
     } 

     @Override 
     public void onFailure(Call<List<Article>> call, final Throwable t) { 
      Toast.makeText(getContext,t.getMessage(),Toast.LENGTH_LONG).show(); 
     } 
    }); 
}

這個適配器類請加「添加」您的適配器內部功能不外部原因會使你的代碼看起來更加糟糕和複雜。

public class HistoryAdapter{ 


private ArrayList<Article> articleList; 

public HistoryAdapter(......){ 
    articleList = new ArrayList<>(); 
    ..... 
} 

..... 

..... 


public void addItem(Article article){ 
    articleList.add(article); 
    notifyDataSetChanged(); 
} 
}

來源

2017-03-15 17:33:32

Android RecyclerView適配器未初始化

回答

相關問題