漢堡包菜單的3行圖標未出現

Question

我有這個使用導航抽屜的活動，但由於某種原因，它始終顯示「向上」箭頭。此活動使用Intent打開，所以我想知道這是否總是顯示「向上」箭頭的原因。

代碼：

@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); 
} 

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() 
     } 
    }; 

    mDrawerLayout.setDrawerListener(mDrawerToggle); 

    // 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(); 
     } 
    }); 
} 

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 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()) { 
     showGlobalContextActionBar(); 
    } 
    super.onCreateOptionsMenu(menu, inflater); 
} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    if (mDrawerToggle.onOptionsItemSelected(item)) { 
     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(); 
} 

/** 
* Callbacks interface that all activities using this fragment must implement. 
*/ 
public interface NavigationDrawerCallbacks { 
    /** 
    * Called when an item in the navigation drawer is selected. 
    */ 
    void onNavigationDrawerItemSelected(int position); 
} 

Answer 1

隨着ActionBarDrawerToggle的新版本，你不必指定漢堡圖標。更新您的Android支持庫v7至少v22.2.0。 以下行添加到您的gradle這個文件的依賴關係：

compile 'com.android.support:appcompat-v7:22.2.0' 

然後初始化它：

mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, R.string.app_name, R.string.app_name) { 
     @Override 
     public void onDrawerClosed(View view) { 
      super.onDrawerClosed(view); 
      // Do whatever you need to do when drawer closed 
     } 

     @Override 
     public void onDrawerOpened(View drawerView) { 
      super.onDrawerOpened(drawerView); 
      // Do whatever you need to do when drawer opened 
     } 
    };