Question

如何将firebase数据库中的所有项目排序到listview？我想要所有只包含共享首选项上保存的用户用户名的项目。这是我的代码如何从firebase获取项目

listView = (ListView) findViewById(R.id.lvMessages);

arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, list_of_rooms);


listView.setAdapter(arrayAdapter);

root.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        Set<String> set = new HashSet<String>();
        Iterator i = dataSnapshot.getChildren().iterator();

        while(i.hasNext()){
            set.add(((DataSnapshot)i.next()).getKey());
        }
        list_of_rooms.clear();
        list_of_rooms.addAll(set);

        arrayAdapter.notifyDataSetChanged();
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {

    }
});

Answer 1

您有数据列表的本地副本。只需在本地排序。 E.g。

 root.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            Set<String> set = new HashSet<String>();
            Iterator i = dataSnapshot.getChildren().iterator();

            while(i.hasNext()){
                set.add(((DataSnapshot)i.next()).getKey());
            }
            list_of_rooms.clear();
            list_of_rooms.addAll(set);
Collections.sort(list_of_rooms, new Comparator<String>() {
        @Override
        public int compare(String s1, String s2)
        {
            return  s1.compareTo(s2);
        }
    });
            arrayAdapter.notifyDataSetChanged();
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

Answer 2

            while(i.hasNext()){
                set.add(((DataSnapshot)i.next()).getKey());
            }
            list_of_rooms.clear();
            list_of_rooms.addAll(set);

            arrayAdapter.getFilter().filter(pref.getString("username", "").toString());

            arrayAdapter.notifyDataSetChanged();
        }

如何过滤listview，其中只包含来自firebase的sharedpref中保存的用户名

2 个答案: