java如何在单击ListView条目时切换到另一个片段？

Question

我正在开发一款Android应用程序，并使用带有两个片段的TabLayout，Map和Discovery。在发现片段中，我有一个ListView，用于显示应用程序连接到的设备。我正在尝试添加一个功能，一旦单击ListView中的条目，就会加载映射片段。尝试通过添加代码来实现此功能

Fragment fragment = new MapFragment();
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.content_map,fragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();

到ListView的OnClickListener，其中R.id.content_map是与MapFragment类一起使用的布局文件的id。我找到了上面的代码here。下面是DiscoveryFragment和MapFragment类的定义

public class DiscoveryFragment extends Fragment {
    private DhcpInfo mDhcpInfo = null;
    private ArrayList<String> mArrayList = null;
    private final int TASK_COMPLETE = 1;
    private Handler mHandler = null;
    private final String IP_KEY = "IPs";
    private DiscoveryArrayAdapter mArrayAdapter = null;
    private final String ROBOT_ID = "create2";
    private AppDatabase db = null;
    private int mTaskCounterVar = 0;

    public DiscoveryFragment() {
        // This is an anonymous class which extends the Handler class
        // Handler object is attached to the UI thread
        mHandler = new Handler(Looper.getMainLooper()) {
            @Override
            public void handleMessage(@NonNull Message message) {
                // Get the message string from the Message
                super.handleMessage(message);
                Bundle bundle = message.getData();
                ArrayList<String> msgs = bundle.getStringArrayList(IP_KEY);
                if(msgs != null) {
                    mArrayList.addAll(msgs);
                }
                mArrayAdapter.notifyDataSetChanged();
            }

        };
    }
    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        WifiManager wifiManager = (WifiManager) getContext().getApplicationContext().getSystemService(Context.WIFI_SERVICE);
        mDhcpInfo = wifiManager.getDhcpInfo();
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        ListView listView = null;
        final View discoveryView = inflater.inflate(R.layout.fragment_discovery,container,false);
        mArrayList = new ArrayList<String>();
        new Thread(new FindRobotTask()).start();
        db = Room.databaseBuilder(discoveryView.getContext(), AppDatabase.class, "AppDatabase").build();
        // Setup a new thread to perform network operations

        // Use the ArrayAdapter to register new content to the ListView
        mArrayAdapter = new DiscoveryArrayAdapter(discoveryView.getContext(), mArrayList);

        FloatingActionButton fab = (FloatingActionButton) discoveryView.findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Thread(new FindRobotTask()).start();
                mArrayAdapter.notifyDataSetChanged();
            }
        });

        listView = (ListView)discoveryView.findViewById(R.id.listview);
        listView.setAdapter(mArrayAdapter);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Fragment fragment = new MapFragment();
                FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
                FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
                fragmentTransaction.replace(R.id.content_map,fragment);
                fragmentTransaction.addToBackStack(null);
                fragmentTransaction.commit();
            }
        });

        return discoveryView;
    }

    class FindRobotTask implements Runnable {

        // Implement the run method
        public void run() {
            Bundle bundle = new Bundle();
            Message message = mHandler.obtainMessage();
            ArrayList<String> ipArrayList = new ArrayList<String>();
            try {
                String msg = "Hello";
                String ip = "";
                InetAddress group = InetAddress.getByName("224.3.29.71");
                MulticastSocket sock = new MulticastSocket();
                sock.joinGroup(group);
                byte[] bytes = msg.getBytes();
                DatagramPacket hi = new DatagramPacket(bytes, bytes.length, group, 10000);
                sock.send(hi);
                byte[] buf = new byte[1000];
                String recvMsg = "";
                InetAddress address = null;
                for(int i = 0; i < 10 && !"iRobot Create 2".equals(recvMsg); i++) {
                    DatagramPacket recv = new DatagramPacket(buf, buf.length);
                    sock.receive(recv);
                    recvMsg = new String(recv.getData(), 0, recv.getLength());
                    address = recv.getAddress();
                }
                ip = address.getHostAddress();
                List<Robot> robotsWithIp = db.robotDao().loadByIp(ip);

                // If a corresponding table entry is not found,
                // add the robot to the database.
                if(mTaskCounterVar == 0) {
                    if(robotsWithIp.size() == 0) {
                        ipArrayList.add(recvMsg + ": " + ip);
                        Robot robot = new Robot(recvMsg, ip);
                        db.robotDao().insert(robot);
                        mTaskCounterVar++;
                        // Else load the robot from the database
                    } else if (robotsWithIp.size() > 0) {
                        for(Robot robot : robotsWithIp) {
                            if(robot != null) {
                                ipArrayList.add(robot.name + ": " + robot.ip);
                            }
                        }
                        mTaskCounterVar++;
                    }
                }
                sock.leaveGroup(group);
                sock.close();
            } catch(UnknownHostException e) {
                e.printStackTrace();
            } catch(IOException e) {
                e.printStackTrace();
            }

            bundle.putStringArrayList(IP_KEY,ipArrayList);
            message.setData(bundle);
            mHandler.sendMessage(message);
        }
    }

}

public class MapFragment extends Fragment {
    public MapFragment() {

    }
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_map, container, false);
    }
}

但是，当我运行应用程序时，在列表视图中单击条目时，发现片段不会被MapFragment替换。有人能告诉我哪里出了问题吗？我相信它可能是传递给replace方法的id，但我真的不确定