Exemplo n.º 1
0
  /**
   * Deactivate the current activity, find the next one from our ActivityMapper, and start it.
   *
   * <p>The current activity's widget will be hidden immediately, which can cause flicker if the
   * next activity provides its widget asynchronously. That can be minimized by decent caching.
   * Perenially slow activities might mitigate this by providing a widget immediately, with some
   * kind of "loading" treatment.
   */
  public void onPlaceChange(PlaceChangeEvent event) {
    Activity nextActivity = getNextActivity(event);

    Throwable caughtOnStop = null;
    Throwable caughtOnCancel = null;
    Throwable caughtOnStart = null;

    if (nextActivity == null) {
      nextActivity = NULL_ACTIVITY;
    }

    if (currentActivity.equals(nextActivity)) {
      return;
    }

    if (startingNext) {
      // The place changed again before the new current activity showed its
      // widget
      caughtOnCancel = tryStopOrCancel(false);
      currentActivity = NULL_ACTIVITY;
      startingNext = false;
    } else if (!currentActivity.equals(NULL_ACTIVITY)) {
      showWidget(null);

      /*
       * Kill off the activity's handlers, so it doesn't have to worry about
       * them accidentally firing as a side effect of its tear down
       */
      stopperedEventBus.removeHandlers();
      caughtOnStop = tryStopOrCancel(true);
    }

    currentActivity = nextActivity;

    if (currentActivity.equals(NULL_ACTIVITY)) {
      showWidget(null);
    } else {
      startingNext = true;
      caughtOnStart = tryStart();
    }

    if (caughtOnStart != null || caughtOnCancel != null || caughtOnStop != null) {
      Set<Throwable> causes = new LinkedHashSet<Throwable>();
      if (caughtOnStop != null) {
        causes.add(caughtOnStop);
      }
      if (caughtOnCancel != null) {
        causes.add(caughtOnCancel);
      }
      if (caughtOnStart != null) {
        causes.add(caughtOnStart);
      }

      throw new UmbrellaException(causes);
    }
  }
Exemplo n.º 2
0
 private Throwable tryStopOrCancel(boolean stop) {
   Throwable caughtOnStop = null;
   try {
     if (stop) {
       currentActivity.onStop();
     } else {
       currentActivity.onCancel();
     }
   } catch (Throwable t) {
     caughtOnStop = t;
   } finally {
     /*
      * Kill off the handlers again in case it was naughty and added new ones
      * during onstop or oncancel
      */
     stopperedEventBus.removeHandlers();
   }
   return caughtOnStop;
 }