PresenterManager.java 文件源码

/**
 * Get the Activity of a context. This is typically used to determine the hosting activity of a
 * {@link View}
 *
 * @param context The context
 * @return The Activity or throws an Exception if Activity couldnt be determined
 */
@NonNull public static Activity getActivity(@NonNull Context context) {
  if (context == null) {
    throw new NullPointerException("context == null");
  }
  if (context instanceof Activity) {
    return (Activity) context;
  }

  while (context instanceof ContextWrapper) {
    if (context instanceof Activity) {
      return (Activity) context;
    }
    context = ((ContextWrapper) context).getBaseContext();
  }
  throw new IllegalStateException("Could not find the surrounding Activity");
}