如果我最终以Stream[Id, A]，translate Pure Id ~> Pure效果Stream[Option, A]。
但是，如果我最终得到了一个不同的严格效果类型的流，例如Option[Vector[A]]，如何将其转换为Sync（或其他内容）？到目前为止，我发现的最好的方法是将流转换为 具有Sync实例的其他类型，运行流，但是将其转换回来并不是直接的Throwable承认所有Option为失败，而None自然只允许public class MyLifecycleHandler implements Application.ActivityLifecycleCallbacks {
private static int resumed;
private static int paused;
private static int started;
private static int stopped;
private static String currentActivity;
public static String getCurrentActivity() {
return currentActivity;
}
@Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
currentActivity = activity.getClass().getSimpleName();
}
@Override
public void onActivityDestroyed(Activity activity) {
}
@Override
public void onActivityResumed(Activity activity) {
++resumed;
}
@Override
public void onActivityPaused(Activity activity) {
++paused;
android.util.Log.w("test", "application is in foreground: " + (resumed > paused));
// send broadcast from here to the service
sendBroadcast()
}
@Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
}
@Override
public void onActivityStarted(Activity activity) {
++started;
}
@Override
public void onActivityStopped(Activity activity) {
++stopped;
android.util.Log.w("test", "application is visible: " + (started > stopped));
}
public static boolean isApplicationVisible() {
return started > stopped;
}
public static boolean isApplicationInForeground() {
return resumed > paused;
}
}
。接近这个的更好方法是什么？