Agera 一個來自谷歌官方的超輕量Android庫

Agera（在瑞典語中表示“行動”）是超輕量Android庫，可以為生命周期內不同形式的Android應用組件（如：活動組件Activities）或對象（如：視圖對象Views）提供待用數據。該Android庫引入函數響應編程機制，有利于數據處理過程中清晰劃分時間、地點、要素等內容，因此只需使用擬自然語言簡單說明便能描述復雜的異步處理過程。

下列演示了Agera的某些功能。該Wiki內容和Java文檔說了Agera 各部分工作機制。

public class AgeraActivity extends Activity implements Receiver<Bitmap>, Updatable {
      private static final ExecutorService NETWORK_EXECUTOR = newSingleThreadExecutor();
      private static final ExecutorService DECODE_EXECUTOR = newSingleThreadExecutor();

      private Repository<Result<Bitmap>> background;
      private ImageView backgroundView;

      @Override
      protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // Set the content view
        setContentView(R.layout.activity_main);

        // Find the background view
        backgroundView = (ImageView) findViewById(R.id.background);

        // Create a repository containing the result of a bitmap request. Initially absent, but
        // configured to fetch the bitmap over the network based on display size.
        background = repositoryWithInitialValue(Result.<Bitmap>absent())
            .observe() // Optionally refresh the bitmap on events. In this case, never
            .onUpdatesPerLoop() // Refresh per Looper thread loop. In this case, never
            .getFrom(new Supplier<HttpRequest>() {
              @NonNull
              @Override
              public HttpRequest get() {
                DisplayMetrics displayMetrics = getResources().getDisplayMetrics();
                int size = Math.max(displayMetrics.heightPixels, displayMetrics.widthPixels);
                return httpGetRequest(
                    "http://www.gravatar.com/avatar/4df6f4fe5976df17deeea19443d4429d?s=" + size)
                    .compile();
              }
            }) // Supply an HttpRequest based on the display size
            .goTo(NETWORK_EXECUTOR) // Change execution to the network executor
            .attemptTransform(httpFunction())
            .orSkip() // Make the actual http request, skip on failure
            .goTo(DECODE_EXECUTOR) // Change execution to the decode executor
            .thenTransform(new Function<HttpResponse, Result<Bitmap>>() {
              @NonNull
              @Override
              public Result<Bitmap> apply(@NonNull HttpResponse response) {
                byte[] body = response.getBody();
                return absentIfNull(decodeByteArray(body, 0, body.length));
              }
            }) // Decode the successful http response to the result of a bitmap, absent on failure
            .onDeactivation(SEND_INTERRUPT) // Interrupt http request/decode on deactivation
            .compile(); // Create the repository
      }

      @Override
      protected void onResume() {
        super.onResume();
        background.addUpdatable(this); // Start listening to the repository, triggering the flow
      }

      @Override
      protected void onPause() {
        super.onPause();
        background.removeUpdatable(this); // Stop listening to the repository, deactivating it
      }

      @Override
      public void update() {
        // Called as the repository is updated
        background.get().ifSucceededSendTo(this); // If containing a valid bitmap, send to accept below
      }

      @Override
      public void accept(@NonNull Bitmap background) {
        backgroundView.setImageBitmap(background); // Set the background bitmap to the background view
      }
    }

本站原創，轉載時保留以下信息：

本文轉自：深度開源（open-open.com）

原文標題：Agera  一個來自谷歌官方的超輕量Android庫

原文地址：http://www.baiduhome.net/lib/view/open1461140484040.html