Android: cómo cambiar fragmentos en el panel de navegación

Soy bastante nuevo en la progtwigción de Android, pero lo he estado haciendo bastante bien hasta ahora. He leído muchas respuestas a esta pregunta, pero parece que no puedo hacer que el mío funcione. Básicamente lo que tengo es una actividad principal con un cajón de navegación. Tengo dos fragmentos inicializados correctamente con el correspondiente diseño de fragmento xmls. Actualmente puedo hacer que aparezca mi primer fragmento cuando se inicia la aplicación y cuando hago clic en cada elemento del cajón, los títulos cambian; sin embargo, el fragmento permanece igual. ¿Alguna sugerencia? Lo que creo que es código relevante está debajo (no se muestra el código para NavigationDrawerFragment.java con el código necesario creado automáticamente por Eclipse). ¡Gracias por adelantado!

public class MainActivity extends Activity implements NavigationDrawerFragment.NavigationDrawerCallbacks { /** * Fragment managing the behaviors, interactions and presentation of the navigation drawer. */ private NavigationDrawerFragment mNavigationDrawerFragment; /** * Used to store the last screen title. For use in {@link #restreActionBar()}. */ private CharSequence mTitle; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mNavigationDrawerFragment = (NavigationDrawerFragment) getFragmentManager().findFragmentById(R.id.navigation_drawer); mTitle = getTitle(); // Set up the drawer. mNavigationDrawerFragment.setUp( R.id.navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout)); } @Override public void onNavigationDrawerItemSelected(int position) { // update the main content by replacing fragments FragmentManager fragmentManager = getFragmentManager(); fragmentManager.beginTransaction() .replace(R.id.content_frame, PlaceholderFragment.newInstance(position + 1)) .commit(); } public void onSectionAttached(int number) { switch (number) { case 1: mTitle = getString(R.string.title_home); break; case 2: mTitle = getString(R.string.title_infodirect); break; case 3: mTitle = getString(R.string.title_trailmap); break; case 4: mTitle = getString(R.string.title_poi); break; case 5: mTitle = getString(R.string.title_photomap); break; case 6: mTitle = getString(R.string.title_report); break; case 7: mTitle = getString(R.string.title_rulesreg); } } public void restreActionBar() { ActionBar actionBar = getActionBar(); actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD); actionBar.setDisplayShowTitleEnabled(true); actionBar.setTitle(mTitle); } @Override public boolean onCreateOptionsMenu(Menu menu) { if (!mNavigationDrawerFragment.isDrawerOpen()) { // Only show items in the action bar relevant to this screen // if the drawer is not showing. Otherwise, let the drawer // decide what to show in the action bar. getMenuInflater().inflate(R.menu.overview, menu); restreActionBar(); return true; } return super.onCreateOptionsMenu(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(); if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } /** * A placeholder fragment containing a simple view. */ public static class PlaceholderFragment extends Fragment { /** * The fragment argument representing the section number for this * fragment. */ private static final String ARG_SECTION_NUMBER = "section_number"; /** * Returns a new instance of this fragment for the given section * number. */ public static PlaceholderFragment newInstance(int sectionNumber) { PlaceholderFragment fragment = new PlaceholderFragment(); Bundle args = new Bundle(); args.putInt(ARG_SECTION_NUMBER, sectionNumber); fragment.setArguments(args); return fragment; } public PlaceholderFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_home, container, false); return rootView; } @Override public void onAttach(Activity activity) { super.onAttach(activity); ((MainActivity) activity).onSectionAttached( getArguments().getInt(ARG_SECTION_NUMBER)); } } public static class InfoDirectFragment extends Fragment { /** * The fragment argument representing the section number for this * fragment. */ private static final String ARG_SECTION_NUMBER = "section_number"; /** * Returns a new instance of this fragment for the given section * number. */ public static InfoDirectFragment newInstance(int sectionNumber) { InfoDirectFragment fragment = new InfoDirectFragment(); Bundle args = new Bundle(); args.putInt(ARG_SECTION_NUMBER, sectionNumber); fragment.setArguments(args); return fragment; } public InfoDirectFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_infodirect, container, false); return rootView; } @Override public void onAttach(Activity activity) { super.onAttach(activity); ((MainActivity) activity).onSectionAttached( getArguments().getInt(ARG_SECTION_NUMBER)); } } } 

¡Sigue este enlace! para más detalles y uso

 private class DrawerItemClickListener implements ListView.OnItemClickListener { @Override public void onItemClick(AdapterView parent, View view, int position, long id) { selectItem(position); } } 

y

 private void selectItem(int position) { FragmentManager fragmentManager = getSupportFragmentManager(); FragmentTransaction ft = fragmentManager.beginTransaction(); switch (position) { case 0: ft.replace(R.id.content_frame, new Fragment1, Constants.TAG_FRAGMENT).commit(); break; case 1: ft.replace(R.id.content_frame, new Fragment2, Constants.TAG_FRAGMENT); ft.commit(); break; } mDrawerList.setItemChecked(position, true); setTitle(title[position]); // Close drawer mDrawerLayout.closeDrawer(mDrawerList); } 
 @Override public void onNavigationDrawerItemSelected(int position) { // update the main content by replacing fragments FragmentManager fragmentManager = getSupportFragmentManager(); if (position == 0) { fragmentManager.beginTransaction() .replace(R.id.container, FirstFragment.newInstance()) .commit(); } else if (position == 1) { fragmentManager.beginTransaction() .replace(R.id.container, SecondFragment.newInstance()) .commit(); } else if (position == 2) { fragmentManager.beginTransaction() .replace(R.id.container, ThridFragment.newInstance()) .commit(); } } 

y crear fragmento

 public class FirstFragment extends Fragment { public static FirstFragment newInstance() { FirstFragment fragment = new FirstFragment(); return fragment; } public FirstFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_first, container, false); return rootView; } @Override public void onAttach(Activity activity) { super.onAttach(activity); ((MainActivity) activity).onSectionAttached(1); } } 

Estaba trabajando con el Cajón de navegación basado en lo que Eclipse también generó (el tuyo parece que también fue hecho con él), y lo he recortado un poco para que no sea del todo tonto. También hice algo de magia negra en algunos puntos, porque estaba obteniendo errores tontos que he reparado a lo largo del tiempo (como no poder actualizar el título de la barra de acciones en la retroceso, o que si giras la pantalla, entonces el elemento en el índice 0 es recreado por la actividad):

NavigationDrawerActivity:

 public class NavigationDrawerActivity extends ActionBarActivity implements NavigationDrawerFragment.NavigationDrawerCallbacks { /** * Fragment managing the behaviors, interactions and presentation of the navigation drawer. */ private NavigationDrawerFragment mNavigationDrawerFragment; /** * Used to store the last screen title. For use in {@link #restreActionBar()}. */ private CharSequence mTitle; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mNavigationDrawerFragment = (NavigationDrawerFragment) getSupportFragmentManager() .findFragmentById(R.id.navigation_drawer); mTitle = getString(R.string.drawer_0); // Set up the drawer. mNavigationDrawerFragment.setUp(R.id.navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout)); getSupportFragmentManager().addOnBackStackChangedListener(new OnBackStackChangedListener() { public void onBackStackChanged() { int backCount = getSupportFragmentManager().getBackStackEntryCount(); if (backCount == 0) { finish(); } else { Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.container); mTitle = getString(((GetActionBarTitle) fragment).getActionBarTitleId()); restreActionBar(); } } }); if (savedInstanceState != null) { this.onBackPressed(); } } public void restreActionBar() { ActionBar actionBar = getSupportActionBar(); actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD); actionBar.setDisplayShowTitleEnabled(true); actionBar.setTitle(mTitle); } @Override public boolean onCreateOptionsMenu(Menu menu) { if (!mNavigationDrawerFragment.isDrawerOpen()) { // Only show items in the action bar relevant to this screen // if the drawer is not showing. Otherwise, let the drawer // decide what to show in the action bar. getMenuInflater().inflate(R.menu.main, menu); restreActionBar(); return true; } return super.onCreateOptionsMenu(menu); } @Override public void onNavigationDrawerItemSelected(int position) { // update the main content by replacing fragments FragmentManager fragmentManager = getSupportFragmentManager(); boolean addToBackStack = true; Fragment fragment = null; switch (position) { case 0: fragment = new Fragment0(); break; case 1: fragment = new Fragment1(); break; case 2: fragment = new Fragment2(); break; case 3: fragment = new Fragment3(); break; case 4: fragment = new Fragment4(); break; case 5: logout(); default: Log.w(this.getClass().getSimpleName(), "Reached Default in onNavigationDrawerItemSelected!"); break; } if (fragment != null) { FragmentTransaction ft = fragmentManager.beginTransaction(); ft.replace(R.id.container, fragment); if (addToBackStack == true) { ft.addToBackStack(null); } ft.commit(); mTitle = getString(((GetActionBarTitle) fragment).getActionBarTitleId()); restreActionBar(); } } public void logout() { this.finish(); } } 

El insidioso “GetActionBarTitle”:

  public interface GetActionBarTitle { public int getActionBarTitleId(); } 

El NavigationDrawerFragment generado (no creo que haya cambiado esto en absoluto):

 public class NavigationDrawerFragment extends Fragment { /** * Remember the position of the selected item. */ private static final String STATE_SELECTED_POSITION = "selected_navigation_drawer_position"; /** * Per the design guidelines, you should show the drawer on launch until the user manually expands * it. This shared * preference tracks this. */ private static final String PREF_USER_LEARNED_DRAWER = "navigation_drawer_learned"; /** * A pointer to the current callbacks instance (the Activity). */ private NavigationDrawerCallbacks mCallbacks; /** * Helper component that ties the action bar to the navigation drawer. */ private ActionBarDrawerToggle mDrawerToggle; private DrawerLayout mDrawerLayout; private ListView mDrawerListView; private View mFragmentContainerView; private int mCurrentSelectedPosition = 0; private boolean mFromSavedInstanceState; private boolean mUserLearnedDrawer; public NavigationDrawerFragment() { } /** * Callbacks interface that all activities using this fragment must implement. */ public static interface NavigationDrawerCallbacks { /** * Called when an item in the navigation drawer is selected. */ void onNavigationDrawerItemSelected(int position); } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Read in the flag indicating whether or not the user has demonstrated awareness of the // drawer. See PREF_USER_LEARNED_DRAWER for details. SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity()); mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false); if (savedInstanceState != null) { mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION); mFromSavedInstanceState = true; } // Select either the default item (0) or the last selected item. selectItem(mCurrentSelectedPosition); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); // Indicate that this fragment would like to influence the set of actions in the action bar. setHasOptionsMenu(true); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { mDrawerListView = (ListView) inflater.inflate(R.layout.fragment_navigation_drawer, container, false); mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView parent, View view, int position, long id) { selectItem(position); } }); String[] drawerTitles = new String[] { getString(R.string.drawer_0), getString(R.string.drawer_1), getString(R.string.drawer_2), getString(R.string.drawer_3), getString(R.string.drawer_4), getString(R.string.drawer_5) }; mDrawerListView.setAdapter(new ArrayAdapter(getActionBar().getThemedContext(), android.R.layout.simple_list_item_1, android.R.id.text1, drawerTitles)); mDrawerListView.setItemChecked(mCurrentSelectedPosition, true); return mDrawerListView; } public boolean isDrawerOpen() { return mDrawerLayout != null && mDrawerLayout.isDrawerOpen(mFragmentContainerView); } /** * Users of this fragment must call this method to set up the navigation drawer interactions. * * @param fragmentId * The android:id of this fragment in its activity's layout. * @param drawerLayout * The DrawerLayout containing this fragment's UI. */ public void setUp(int fragmentId, DrawerLayout drawerLayout) { mFragmentContainerView = getActivity().findViewById(fragmentId); mDrawerLayout = drawerLayout; // set a custom shadow that overlays the main content when the drawer opens mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START); // set up the drawer's list view with items and click listener ActionBar actionBar = getActionBar(); actionBar.setDisplayHomeAsUpEnabled(true); actionBar.setHomeButtonEnabled(true); // ActionBarDrawerToggle ties together the the proper interactions // between the navigation drawer and the action bar app icon. mDrawerToggle = new ActionBarDrawerToggle(getActivity(), /* host Activity */ mDrawerLayout, /* DrawerLayout object */ R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */ R.string.navigation_drawer_open, /* "open drawer" description for accessibility */ R.string.navigation_drawer_close /* "close drawer" description for accessibility */ ) { @Override public void onDrawerClosed(View drawerView) { super.onDrawerClosed(drawerView); if (!isAdded()) { return; } getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu() } @Override public void onDrawerOpened(View drawerView) { super.onDrawerOpened(drawerView); if (!isAdded()) { return; } if (!mUserLearnedDrawer) { // The user manually opened the drawer; store this flag to prevent auto-showing // the navigation drawer automatically in the future. mUserLearnedDrawer = true; SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity()); sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true).apply(); } getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu() } }; // If the user hasn't 'learned' about the drawer, open it to introduce them to the drawer, // per the navigation drawer design guidelines. if (!mUserLearnedDrawer && !mFromSavedInstanceState) { mDrawerLayout.openDrawer(mFragmentContainerView); } // Defer code dependent on restration of previous instance state. mDrawerLayout.post(new Runnable() { @Override public void run() { mDrawerToggle.syncState(); } }); mDrawerLayout.setDrawerListener(mDrawerToggle); } private void selectItem(int position) { mCurrentSelectedPosition = position; if (mDrawerListView != null) { mDrawerListView.setItemChecked(position, true); } if (mDrawerLayout != null) { mDrawerLayout.closeDrawer(mFragmentContainerView); } if (mCallbacks != null) { mCallbacks.onNavigationDrawerItemSelected(position); } } @Override public void onAttach(Activity activity) { super.onAttach(activity); try { mCallbacks = (NavigationDrawerCallbacks) activity; } catch (ClassCastException e) { throw new ClassCastException("Activity must implement NavigationDrawerCallbacks."); } } @Override public void onDetach() { super.onDetach(); mCallbacks = null; } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition); } @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); // Forward the new configuration the drawer toggle component. mDrawerToggle.onConfigurationChanged(newConfig); } @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { // If the drawer is open, show the global app actions in the action bar. See also // showGlobalContextActionBar, which controls the top-left area of the action bar. if (mDrawerLayout != null && isDrawerOpen()) { inflater.inflate(R.menu.global, menu); showGlobalContextActionBar(); } super.onCreateOptionsMenu(menu, inflater); } @Override public boolean onOptionsItemSelected(MenuItem item) { if (mDrawerToggle.onOptionsItemSelected(item)) { return true; } /* * if (item.getItemId() == R.id.action_example) * { * Toast.makeText(getActivity(), "Example action.", Toast.LENGTH_SHORT).show(); * return true; * } */ return super.onOptionsItemSelected(item); } /** * Per the navigation drawer design guidelines, updates the action bar to show the global app * 'context', rather than * just what's in the current screen. */ private void showGlobalContextActionBar() { ActionBar actionBar = getActionBar(); actionBar.setDisplayShowTitleEnabled(true); actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD); actionBar.setTitle(R.string.app_name); } private ActionBar getActionBar() { return ((ActionBarActivity) getActivity()).getSupportActionBar(); } } 

Un fragmento de ejemplo creado por este cajón de navegación:

  public class MyFragment extends Fragment implements GetActionBarTitle, OnClickListener { private int titleId; private Button btn0; private Button btn1; private Button btn2; public MyFragment() { super(); titleId = R.string.drawer_myfragment_title; } @Override public int getActionBarTitleId() { return titleId; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_myfragment, container, false); return rootView; } @Override public void onViewCreated(View view, Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); btn0 = (Button) view.findViewById(R.id.btn0); btn1 = (Button) view.findViewById(R.id.btn1); btn2 = (Button) view.findViewById(R.id.btn2); btn0.setOnClickListener(this); btn1.setOnClickListener(this); btn2.setOnClickListener(this); } @Override public void onClick(View v) { if (btn0 == v) { } else if (btn1 == v) { } else if (btn2 == v) { } } } 

Espero que eso funcione como tu quisiste. Tenía que hacer magia con BackStackListener y cosas para que funcionen correctamente.

Sé que esto es bastante antiguo, pero me gustaría compartir algunos artículos que he escrito sobre la navegación de Cajón de aplicaciones y Fragmentos. Están actualizados con las últimas muestras (al menos para 2017). No dude en echar un vistazo a:

https://aarcoraci.wordpress.com/2017/02/13/android-tutorial-drawer-and-fragment-navigation-made-easyier/

https://aarcoraci.wordpress.com/2017/02/14/android-drawer-and-fragment-navigation-a-more-real-life-scenario/