如何從改造onResponse（）更新Activity/Fragment UI？

Question

我想爲我的下一個Android項目使用Retrofit 2.1.0。我想用設計模式，並因此創造單獨的類爲每個REST調用即

IBalanceService.java

public Interface IBalanceService{ 
    @GET("users/{username}") 
    void getUser(@Path("username") String username, Callback<User> cb); 
} 

BalanceRestClient.java

public class BalanceRestClient{ 

    String username = "Makarov"; 

    Retrofit retrofit = new Retrofit.Builder() 
           .baseUrl("http://hovermind.com") 
           .addConverterFactory(GsonConverterFactory.create()) 
           .addCallAdapterFactory(rxAdapter) 
           .build(); 

    IBalanceService bs = retrofit.create(IBalanceService.class); 


    Call<User> call = apiService.getUser(username); 
    call.enqueue(new Callback<User>() { 

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

      User user = response.body(); 

      // update Activity/Fragment from here 

     } 

     @Override 
     public void onFailure(Call<User> call, Throwable t) { 
     // Log error here since request failed 
     } 

    }); 
} 

BalanceActivity.java

public BalanceActivity extends Activity{ 

    // BalanceRestClient will update some UI elements 
} 

如何從onResponse（）更新我Activity/fragment中的UI？

附加信息：
分鐘SDK：19
目標SDK：23
改造2.1.0與OkHttp和GSON

Answer 1

public class BalanceRestClient { 

      private static BalanceRestClient instance; 
      private IBalanceService request; 

      private BalanceRestClient() { 
       Retrofit retrofit = new Retrofit.Builder() 
         .baseUrl("http://hovermind.com") 
         .addConverterFactory(GsonConverterFactory.create()) 
         .addCallAdapterFactory(rxAdapter) 
         .build(); 

       request = retrofit.create(IBalanceService.class); 
      } 

      public static synchronized BalanceRestClient getInstance() { 
       if (instance == null) 
        instance = new BalanceRestClient(); 

       return instance; 
      } 

      public void getRequest(String userName, YourCustomeCallback callback) { 

       Call<User> call = apiService.getUser(username); 
       call.enqueue(new Callback<User>() { 

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

         User user = response.body(); 

         callback.onResponse(user); 

        } 

        @Override 
        public void onFailure(Call<User> call, Throwable t) { 
         // Log error here since request failed 
        } 

       }); 
      } 
     } 

1. 創建一個單獨的類。它的初始化請求只有一次。
2. 創建一個自定義回調，它將回復您對UI的響應。
3. 調用BalanceRestClient.getInstance.getRequest（params ..）要使用它的位置。

Answer 2

上做一個接口，這樣的：

public interface BalanceListener { 

    void onUserAvailable(User user); 

} 

在你BalanceRestClient有它的一個實例。而在onResponse：

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

     User user = response.body(); 

     listener.onUserAvailable(user); 

    } 

讓您的活動實施BalanceListner：

public class BalanceActivity extends Activity implements BalanceListener { 
       ...... 

     @Override 
     public void onUserAvailable(User user) { 
      // update user views here 
     } 
    }