Android: Können nicht von einem Fragmente zu einem anderen

Question

This is the login screen, which leads to the next screen(Chat Screen)

This is the Chat Screen- which I am unable to navigate to

Ich versuche navigieren bin eine Chat-Funktion, bei dem sowohl das Login und die Chat-Bildschirm fragments.I zu implementieren sind ist keine immer Fehler. Die App navigiert jedoch nicht zum Chat-Bildschirm. Ich weiß nicht, wo ich vermisse. Irgendwelche Vorschläge würden geschätzt.

******** Anmelden Fragment ********

public class LoginFragment extends Fragment { 

private EditText mUsernameView; 
private Button signInButton; 
private String mUsername; 
private Socket mSocket; 

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

    View loginview = inflater.inflate(R.layout.fragment_login, container, false); 

    ChatApplication app = (ChatApplication) getActivity().getApplication(); 
    mSocket = app.getSocket(); 

    // this is the login form 
    mUsernameView = (EditText) loginview.findViewById(R.id.username_input); 
    mUsernameView.setOnEditorActionListener(new TextView.OnEditorActionListener() 
    { 
     @Override 
     public boolean onEditorAction(TextView textView, int id, KeyEvent keyEvent) 
     { 
      if(id == R.id.login || id == EditorInfo.IME_NULL) 
      { 
       attemptLogin(); 
       return true; 
      } 
       return false; 
     } 
    }); 

    signInButton = (Button) loginview.findViewById(R.id.sign_in_button); 
    signInButton.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) 
     { 
      attemptLogin(); 
     } 
    }); 

    mSocket.on("login",onLogin); 

    return loginview; 
} 

@Override 
public void onDestroy() { 
    super.onDestroy(); 

    mSocket.off("login", onLogin); 
} 

/* 
    This method attempts the following 
    1- clears the error message/resets the error message. 
    2- checks if the user has entered valid username 
    3- attempts user login 
*/ 
private void attemptLogin() 
{ 
    mUsernameView.setError(null); //1 
    String username = mUsernameView.getText().toString().trim(); 
    if(TextUtils.isEmpty(username)) //2 
    { 
     mUsernameView.setError("This field is required!"); 
     mUsernameView.requestFocus(); 
     return; 
    } 

    mUsername = username; 

    mSocket.emit("add user", username); //3 
} 

private Emitter.Listener onLogin = new Emitter.Listener() 
{ 
    @Override 
    public void call(Object... args) 
    { 
     JSONObject data = (JSONObject) args[0]; 
     int numUsers; 
     try 
     { 
      numUsers = data.getInt("numUsers"); 
     } 
     catch (JSONException e) 
     { 
      return; 
     } 

     Intent intent = new Intent(); 
     intent.putExtra("username",mUsername); 
     intent.putExtra("numUsers",numUsers); 
     getActivity().setResult(RESULT_OK,intent); 
     getActivity().finish(); 
    } 
}; 

}

************** Fragment Chat *************

public class ChatFragment extends Fragment 
{ 


    private static final int REQUEST_LOGIN = 1; 

    private static final int TYPING_TIMER_LENGTH = 600; 

    private RecyclerView mMessagesView; 
    private EditText mInputMessageView; 
    private List<Message> mMessages = new ArrayList<Message>(); 
    private RecyclerView.Adapter mAdapter; 
    private boolean mTyping = false; 
    private Handler mTypingHandler = new Handler(); 
    private String mUsername; 
    private Socket mSocket; 

    private Boolean isConnected = true; 

    public ChatFragment() { 
     super(); 
    } 

    @Override 
    public void onAttach(Context context) { 
     super.onAttach(context); 
     mAdapter = new MessageAdapter(context, mMessages); 
    } 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     setHasOptionsMenu(true); 

     ChatApplication app = (ChatApplication) getActivity().getApplication(); 
     mSocket = app.getSocket(); 
     mSocket.on(Socket.EVENT_CONNECT,onConnect); 
     mSocket.on(Socket.EVENT_DISCONNECT,onDisconnect); 
     mSocket.on(Socket.EVENT_CONNECT_ERROR, onConnectError); 
     mSocket.on(Socket.EVENT_CONNECT_TIMEOUT, onConnectError); 
     mSocket.on("new message", onNewMessage); 
     mSocket.on("user joined", onUserJoined); 
     mSocket.on("user left", onUserLeft); 
     mSocket.on("typing", onTyping); 
     mSocket.on("stop typing", onStopTyping); 
     mSocket.connect(); 

     startSignIn(); 
    } 

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

    @Override 
    public void onDestroy() { 
     super.onDestroy(); 

     mSocket.disconnect(); 

     mSocket.off(Socket.EVENT_CONNECT, onConnect); 
     mSocket.off(Socket.EVENT_DISCONNECT, onDisconnect); 
     mSocket.off(Socket.EVENT_CONNECT_ERROR, onConnectError); 
     mSocket.off(Socket.EVENT_CONNECT_TIMEOUT, onConnectError); 
     mSocket.off("new message", onNewMessage); 
     mSocket.off("user joined", onUserJoined); 
     mSocket.off("user left", onUserLeft); 
     mSocket.off("typing", onTyping); 
     mSocket.off("stop typing", onStopTyping); 
    } 

    @Override 
    public void onViewCreated(View view, Bundle savedInstanceState) { 
     super.onViewCreated(view, savedInstanceState); 

     mMessagesView = (RecyclerView) view.findViewById(R.id.messages); 
     mMessagesView.setLayoutManager(new LinearLayoutManager(getActivity())); 
     mMessagesView.setAdapter(mAdapter); 

     mInputMessageView = (EditText) view.findViewById(R.id.message_input); 
     mInputMessageView.setOnEditorActionListener(new TextView.OnEditorActionListener() { 
      @Override 
      public boolean onEditorAction(TextView v, int id, KeyEvent event) { 
       if (id == R.id.send || id == EditorInfo.IME_NULL) { 
        attemptSend(); 
        return true; 
       } 
       return false; 
      } 
     }); 
     mInputMessageView.addTextChangedListener(new TextWatcher() { 
      @Override 
      public void beforeTextChanged(CharSequence s, int start, int count, int after) { 
      } 

      @Override 
      public void onTextChanged(CharSequence s, int start, int before, int count) { 
       if (null == mUsername) return; 
       if (!mSocket.connected()) return; 

       if (!mTyping) { 
        mTyping = true; 
        mSocket.emit("typing"); 
       } 

       mTypingHandler.removeCallbacks(onTypingTimeout); 
       mTypingHandler.postDelayed(onTypingTimeout, TYPING_TIMER_LENGTH); 
      } 

      @Override 
      public void afterTextChanged(Editable s) { 
      } 
     }); 

     ImageButton sendButton = (ImageButton) view.findViewById(R.id.send_button); 
     sendButton.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       attemptSend(); 
      } 
     }); 
    } 

    @Override 
    public void onActivityResult(int requestCode, int resultCode, Intent data) { 
     super.onActivityResult(requestCode, resultCode, data); 
     if (Activity.RESULT_OK != resultCode) { 
      getActivity().finish(); 
      return; 
     } 

     mUsername = data.getStringExtra("username"); 
     int numUsers = data.getIntExtra("numUsers", 1); 

     addLog(getResources().getString(R.string.message_welcome)); 
     addParticipantsLog(numUsers); 
    } 

    @Override 
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     inflater.inflate(R.menu.menu_main, menu); 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if (id == R.id.action_leave) { 
      leave(); 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 

    private void addLog(String message) { 
     mMessages.add(new Message.Builder(Message.TYPE_LOG) 
       .message(message).build()); 
     mAdapter.notifyItemInserted(mMessages.size() - 1); 
     scrollToBottom(); 
    } 

    private void addParticipantsLog(int numUsers) { 
     addLog(getResources().getQuantityString(R.plurals.message_participants, numUsers, numUsers)); 
    } 

    private void addMessage(String username, String message) { 
     mMessages.add(new Message.Builder(Message.TYPE_MESSAGE) 
       .username(username).message(message).build()); 
     mAdapter.notifyItemInserted(mMessages.size() - 1); 
     scrollToBottom(); 
    } 

    private void addTyping(String username) { 
     mMessages.add(new Message.Builder(Message.TYPE_ACTION) 
       .username(username).build()); 
     mAdapter.notifyItemInserted(mMessages.size() - 1); 
     scrollToBottom(); 
    } 

    private void removeTyping(String username) { 
     for (int i = mMessages.size() - 1; i >= 0; i--) { 
      Message message = mMessages.get(i); 
      if (message.getType() == Message.TYPE_ACTION && message.getUsername().equals(username)) { 
       mMessages.remove(i); 
       mAdapter.notifyItemRemoved(i); 
      } 
     } 
    } 

    private void attemptSend() { 
     if (null == mUsername) return; 
     if (!mSocket.connected()) return; 

     mTyping = false; 

     String message = mInputMessageView.getText().toString().trim(); 
     if (TextUtils.isEmpty(message)) { 
      mInputMessageView.requestFocus(); 
      return; 
     } 

     mInputMessageView.setText(""); 
     addMessage(mUsername, message); 

     // perform the sending message attempt. 
     mSocket.emit("new message", message); 
    } 

    private void startSignIn() { 
     mUsername = null; 
    /* Error: 
     Intent intent = new Intent(getActivity(), LoginFragment.class); 
     startActivityForResult(intent, REQUEST_LOGIN); 
    */ 

    // Solution 1: for calling a fragment from a fragment 
     Intent intent = new Intent(getActivity(),LoginFragment.class); 
     getActivity().startActivityForResult(intent,REQUEST_LOGIN); 

/* 
    // Solution 2: for calling a fragment from a fragment 
     LoginFragment loginFragment = new LoginFragment(); 
     FragmentManager fManager = getFragmentManager(); 
     FragmentTransaction fTransaction = fManager.beginTransaction(); 
     fTransaction.replace(R.id.id_fragment_chat,loginFragment); 
     fTransaction.addToBackStack(null); 
     fTransaction.commit(); 

*/ 
    } 

    private void leave() { 
     mUsername = null; 
     mSocket.disconnect(); 
     mSocket.connect(); 
     startSignIn(); 
    } 

    private void scrollToBottom() { 
     mMessagesView.scrollToPosition(mAdapter.getItemCount() - 1); 
    } 

    private Emitter.Listener onConnect = new Emitter.Listener() { 
     @Override 
     public void call(Object... args) { 
      getActivity().runOnUiThread(new Runnable() { 
       @Override 
       public void run() { 
        if(!isConnected) { 
         if(null!=mUsername) 
          mSocket.emit("add user", mUsername); 
         Toast.makeText(getActivity().getApplicationContext(), 
           R.string.connect, Toast.LENGTH_LONG).show(); 
         isConnected = true; 
        } 
       } 
      }); 
     } 
    }; 
. 
. 
. 
} 

Answer 1

Über Ihre private void startSignIn() { mUsername = null; Intent intent = new Intent(getActivity(), LoginFragment.class); startActivityForResult(intent, 0); } ... Was möchten Sie tun? Eine andere Aktivität starten? Dann sollten Sie diese Aktivität aufrufen und in dieser Aktivität dieses Fragment hinzufügen. Oder, wenn Sie durch ein anderes Fragment ersetzt werden soll in der gleichen Aktivität, sollten Sie es tun, wie so statt startActivity:

YourFragment fragment = new YourFragment(); 
     FragmentManager fragmentManager = getSupportFragmentManager(); 
     fragmentManager.beginTransaction() 
       .replace(R.id.fragmentContainer, fragment, YOUR_TAG) 
       .commit(); 

Answer 2

Verwenden Struktur Kernfragment anstelle von direkten erstreckt

import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentManager; 

/** 
* 
* This is main core fragment. All fragment defined in this project that extends this fragment. 
* 
* @author viral 
* 
*/ 
public class CoreFragment extends Fragment { 

    private static FragmentManager fm; 
    private CharSequence tabTitle; 

    /** 
    * This method switch fragment. 
    * 
    * @param fragment - from fragment 
    * @param viewReplace - Destination view/container 
    * 
    */ 
    public void switchFragment(Fragment fragment, int viewReplace){ 
     try { 
      FragmentManager fragmentManager = getFragmentManager(); 
      if(fragmentManager != null) 
       fm = fragmentManager; 

      fm.beginTransaction() 
       .replace(viewReplace, fragment) 
       .commit(); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
    } 

    /** 
    * This method switch fragment. 
    * 
    * @param fragment - from fragment 
    * @param viewReplace - Destination view/container 
    * 
    */ 
    public void switchFragmentWithBackstack(Fragment fragment, int viewReplace){ 
     try { 
      FragmentManager fragmentManager = getFragmentManager(); 
      if(fragmentManager != null) 
       fm = fragmentManager; 
      fm.beginTransaction() 
       .replace(viewReplace, fragment) 
       .addToBackStack(null) 
       .commit(); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
    } 
} 

Dann Verwenden Sie die Methode switchFragment/switchFragmentWithBackstack entsprechend Ihrer Anwendung.

Ihr alle Fragment erstreckt sich CoreFragment