LiveData未触发的观察室DAO

Question

试图让LiveData与Room一起工作：

@Entity
public class TimeEntry{
....

@Dao
public interface TimeEntryDAO {
    @Query("SELECT * FROM " + TimeEntry.TIME_TABLE_NAME)
    LiveData<List<TimeEntry>> getAll();
...

protected void onCreate(Bundle savedInstanceState) {
...
        AppDatabase db = AppDatabase.getInstance(mContext);
        db = AppDatabase.getInstance(getApplicationContext());
        tDAO = db.timeEntryDao();
        tDAO.getAll().observe(this, new Observer<List<TimeEntry>>() {
            @Override
            public void onChanged(@Nullable List<TimeEntry> mTimeEntries) {
                if (mTimeEntries != null) {
                    loadSelectedDates(mTimeEntries); //updates a calendarUI
                }
            }
        });
        requestImmediateTimeSync(SyncAdapter.GET_USER_TIMES); //Calls syncAdapter
...

public void onPerformSync(....
...
    AppDatabase db = AppDatabase.getInstance(mContext);
    TimeEntryDAO tDAO;
    tDAO = db.timeEntryDao();
...
    tDAO.insertAll(new TimeEntry(...))
    ...

因为我观察到tdao.getall()，所以我希望在我的活动中，当同步完成时，它会刷新日历。现在，您必须重新加载该活动，以获取在执行同步后放入数据库的数据。我对Room和LiveData很陌生。有什么想法吗？希望我没有拿出太多的代码，这是从一个相当大的应用程序到目前为止。

Answer 1

我最终使用了SyncObserver而不是实时数据，因为SyncAdapter才是我真正应该监视的对象。以下是一些片段：

    ContentResolver.requestSync(MainActivity.mAccount, getApplicationContext().getResources().getString(R.string.authority), bundle);
...
    final int mask = ContentResolver.SYNC_OBSERVER_TYPE_ACTIVE;
    mSyncObserverHandle = ContentResolver.addStatusChangeListener(mask, mSyncStatusObserver);

稍后：

private SyncStatusObserver mSyncStatusObserver = new SyncStatusObserver() {
        @Override
        public void onStatusChanged(final int which) {
        //Check to see if DAO has anything here, if so, run this thread
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                //Do the update thing
            }
         }
}