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Android - So ändern Sie Fragmente in der Navigationsleiste

Ich bin relativ neu in der Android-Programmierung, habe mich aber bisher ziemlich gut geschlagen. Ich habe viele Antworten auf diese Frage gelesen, kann meine aber nicht funktionieren lassen. Im Grunde habe ich eine MainActivity mit einer Navigationsleiste. Ich habe zwei Fragmente, die mit entsprechenden Fragment-Layout-XMLs korrekt initialisiert wurden. Derzeit kann mein erstes Fragment angezeigt werden, wenn die App gestartet wird. Wenn ich auf jedes Element in der Schublade klicke, ändern sich die Titel. Das Fragment bleibt jedoch gleich. Irgendwelche Vorschläge? Der für mich relevante Code ist unten aufgeführt (nicht gezeigt ist der Code für NavigationDrawerFragment.Java mit dem erforderlichen Code, der automatisch von Eclipse erstellt wird). Danke im Voraus!

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 #restoreActionBar()}.
 */
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 restoreActionBar() {
    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);
        restoreActionBar();
        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));
    }
}
}
15
ebenstea13

Folgen Sie diesem link !! für weitere Details und Verwendung 

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

und 

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);
}
16
@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();  
    }  

}

und Fragment erstellen

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);  
   }  
}  
8
CS-

Ich habe mit dem Navigation Drawer gearbeitet, basierend auf dem, was Eclipse ebenfalls generiert hat (Ihr sieht so aus, als wäre es auch damit gemacht worden), und ich habe es ein bisschen beschnitten, so dass es nicht völlig dumm ist. Ich habe an einigen Stellen auch schwarze Magie gemacht, weil ich dumme Fehler bekommen habe, die ich seit einiger Zeit korrigiert habe (z. B., dass der Actionbar-Titel bei Zurückdrücken nicht aktualisiert werden kann oder dass, wenn Sie den Bildschirm drehen, das Element beim Index angezeigt wird 0 wird durch die Aktivität neu erstellt):

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 #restoreActionBar()}.
 */
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());
                restoreActionBar();
            }
        }
    });
    if (savedInstanceState != null)
    {
        this.onBackPressed();
    }
}

public void restoreActionBar()
{
    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);
        restoreActionBar();
        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());
        restoreActionBar();
    }
}

public void logout()
{
    this.finish();
}


}

Der hinterlistige "GetActionBarTitle":

 public interface GetActionBarTitle
 {
     public int getActionBarTitleId();
 }

Das generierte NavigationDrawerFragment (ich glaube nicht, dass ich das geändert habe):

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<String>(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 restoration 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();
}
}

Ein Beispielfragment, das von dieser Navigationsleiste erstellt wird:

 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)
    {

    }
}
}

Ich hoffe, das funktioniert so, wie Sie es beabsichtigt haben. Ich musste mit dem BackStackListener und so etwas zaubern, um richtig zu funktionieren.

2
EpicPandaForce

Ich weiß, dass dies ziemlich alt ist, aber ich möchte ein paar Artikel veröffentlichen, die ich über die Application Drawer- und Fragment-Navigation geschrieben habe. Sie sind mit den neuesten Mustern auf dem neuesten Stand (zumindest für 2017). Fühlen Sie sich frei, einen Blick darauf zu werfen:

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/

1
aarcoraci