如何在android中从firebase实时数据库中获取随机密钥？

dependencies {
    // 其他依赖...
    implementation 'com.google.firebase:firebase-database:20.0.0'
}

import com.google.firebase.database.FirebaseDatabase;

public class MyApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        FirebaseDatabase.getInstance().setPersistenceEnabled(true);
    }
}

- your-database
  - keys
    - key1: "random-key-1"
    - key2: "random-key-2"
    - key3: "random-key-3"
    ...

import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.ValueEventListener;

public class MainActivity extends AppCompatActivity {
    private DatabaseReference keysRef;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // 获取数据库引用
        FirebaseDatabase database = FirebaseDatabase.getInstance();
        keysRef = database.getReference("keys");

        // 添加值事件监听器
        keysRef.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                // 随机获取一个密钥
                String randomKey = getRandomKey(dataSnapshot);
                // 使用随机密钥进行后续操作
                // ...
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                // 处理取消事件
                // ...
            }
        });
    }

    private String getRandomKey(DataSnapshot dataSnapshot) {
        // 获取所有密钥
        List<String> keys = new ArrayList<>();
        for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
            String key = snapshot.getKey();
            keys.add(key);
        }

        // 随机选择一个密钥
        Random random = new Random();
        int index = random.nextInt(keys.size());
        return keys.get(index);
    }
}