小编Sim*_*ani的帖子

我开始将RxJava与SqlBrite结合使用,我遇到了zip运算符的一些问题.

假设我有2个课程,User并且Tweet.

public class User {
    public long id;
    public List<Tweet> users;
    ...
}

public class Tweet {
    public long id;
    public User poster;
    ...
}

和他们各自的SQLite表:

user
---------
id INTEGER PRIMARY KEY

tweet
---------
id INTEGER PRIMARY KEY
poster_id INTEGER
FOREIGN KEY(poster_id) REFERENCES user(id)

和他们各自的SqlBrite DAO

userDAO的:

public class UserDao {
    private final BriteDatabase briteDb;
    private final TweetDAO tweetDao;

    ...

    public Observable<List<User>> getUsersWithTheirTweets() {
        Observable<User> usersObs = briteDb.createQuery("user", "SELECT * FROM …

我有一个ListFragment我使用注册上下文菜单的地方registerForContextMenu()，我覆盖了onCreateContextMenu(). 问题是onCreateContextMenu()当我长按任何项目时从未调用过。

这是一些代码：

public class List_F extends ListFragment {
    @Override
    public void onActivityCreated(Bundle arg0) {
        super.onActivityCreated(arg0);

        registerForContextMenu(getListView());

        setListAdapter(...);
        setListShown(false);

        // launch cursor loader
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v,
                                    ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater inflater = getActivity().getMenuInflater();
        inflater.inflate(R.menu.menu, menu);
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
        int i = item.getItemId();
        if (i == R.id.menu_item_delete) {
            delete(info.id);
            return true;
        } else {
            return super.onContextItemSelected(item); …