Android - Versuch, virtuelle Methode ‚Leere android.support.v4.app.Fragment.setMenuVisibility (boolean)‘ auf ein Null-Objekt Referenz

Question

Hier ist die vollständige Stack-Trace des Fehlers aufzurufen: http://pastebin.com/5dQHkUw3

Der Fehler gestartet erst erscheinen, nachdem ich begonnen habe, Fragmente im Projekt zu verwenden, weil ich JSON-Feeds geben möchte. Es war in Ordnung, bevor, als ich die Schaffung Tabs, NavigationDrawer usw.

MainActivity.java

public class MainActivity erweitert ActionBarActivity implementiert MaterialTabListener {

private Toolbar mToolbar; 
private NavigationDrawerFragment mDrawerFragment; 
private DrawerLayout mDrawerLayout; 

private MaterialTabHost mTabHost; 
private ViewPager mViewPager; 

public static final int SERVICES_ALL = 1; 
public static final int SERVICES_FEATURED = 2; 
public static final int SERVICES_NEW = 3; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main_appbar); 

    mToolbar = (Toolbar) findViewById(R.id.app_bar); 
    setSupportActionBar(mToolbar); 
    getSupportActionBar().setDisplayShowHomeEnabled(true); 

    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout); 
    mDrawerFragment = (NavigationDrawerFragment) getSupportFragmentManager().findFragmentById(R.id.fragment_navigation_drawer); 
    mDrawerFragment.setUp(R.id.fragment_navigation_drawer, mDrawerLayout, mToolbar); 

    mTabHost = (MaterialTabHost) findViewById(R.id.materialTabHost); 
    mViewPager = (ViewPager) findViewById(R.id.viewPager); 

    MyPagerAdapter adapter = new MyPagerAdapter(getSupportFragmentManager()); 
    mViewPager.setAdapter(adapter); 
    mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener(){ 
     @Override 
     public void onPageSelected(int position) { 
      mTabHost.setSelectedNavigationItem(position); 
     } 
    }); 

    for(int i=0; i<adapter.getCount(); i++){ 
     mTabHost.addTab(
       mTabHost.newTab(). 
         setText(adapter.getPageTitle(i)). 
         setTabListener(this) 
     ); 
    } 
} 

@Override 
public void onTabSelected(MaterialTab materialTab) { 
    mViewPager.setCurrentItem(materialTab.getPosition()); 
} 

@Override 
public void onTabReselected(MaterialTab materialTab) { 

} 

@Override 
public void onTabUnselected(MaterialTab materialTab) { 

} 

private class MyPagerAdapter extends FragmentStatePagerAdapter{ 
    FragmentManager fragmentManager; 

    public MyPagerAdapter(FragmentManager fm) { 
     super(fm); 
     fragmentManager = fm; 
    } 

    @Override 
    public Fragment getItem(int num) { 
     Fragment fragment = null; 
     switch (num){ 
      case SERVICES_ALL: 
       fragment = FragmentAll.newInstance("",""); 
       break; 
      case SERVICES_FEATURED: 
       fragment = FragmentFeatured.newInstance("",""); 
       break; 
      case SERVICES_NEW: 
       fragment = FragmentNew.newInstance("",""); 
       break; 
     } 
     return fragment; 
    } 

    @Override 
    public int getCount() { 
     return 3; 
    } 

    public CharSequence getPageTitle(int position){ 
     return getResources().getStringArray(R.array.tabs)[position]; 
    } 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    getMenuInflater().inflate(R.menu.menu_main, menu); 
    return true; 
} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    int id = item.getItemId(); 

    if (id == R.id.action_settings) { 
     Toast.makeText(this, "Hey you just hit " + item.getTitle(), Toast.LENGTH_LONG).show(); 
     return true; 
    } 

    if (id == R.id.action_next) { 
     startActivity(new Intent(this, DetailActivity.class)); 
    } 

    return super.onOptionsItemSelected(item); 
} 

}

FragmentAll.java (Die anderen 2 Fragmente sind FragmentAll ähnlich.)

public class FragmentAll Fragment reicht {

private static final String ARG_PARAM1 = "param1"; 
private static final String ARG_PARAM2 = "param2"; 

private String mParam1; 
private String mParam2; 

public static FragmentAll newInstance(String param1, String param2) { 
    FragmentAll fragment = new FragmentAll(); 
    Bundle args = new Bundle(); 
    args.putString(ARG_PARAM1, param1); 
    args.putString(ARG_PARAM2, param2); 
    fragment.setArguments(args); 
    return fragment; 
} 

public FragmentAll() { 
    // Required empty public constructor 
} 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    if (getArguments() != null) { 
     mParam1 = getArguments().getString(ARG_PARAM1); 
     mParam2 = getArguments().getString(ARG_PARAM2); 
    } 
} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    // Inflate the layout for this fragment 
    return inflater.inflate(R.layout.fragment_all, container, false); 
} 
} 

Die Stacktrace:

android.support.v4.app.Fragment.setMenuVisibility(boolean)' on a null object reference 
      at android.support.v4.app.FragmentStatePagerAdapter.instantiateItem(FragmentStatePagerAdapter.java:116) 
      at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:836) 
      at android.support.v4.view.ViewPager.populate(ViewPager.java:986) 
      at android.support.v4.view.ViewPager.populate(ViewPager.java:918) 
      at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1440) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) 
      at android.support.v7.internal.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:124) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) 
      at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2560) 
      at android.view.View.measure(View.java:17430) 
      at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2001) 
      at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1166) 
      at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1372) 
      at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054) 
      at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779) 
      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767) 
      at android.view.Choreographer.doCallbacks(Choreographer.java:580) 
      at android.view.Choreographer.doFrame(Choreographer.java:550) 
      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753) 
      at android.os.Handler.handleCallback(Handler.java:739) 
      at android.os.Handler.dispatchMessage(Handler.java:95) 
      at android.os.Looper.loop(Looper.java:135) 
      at android.app.ActivityThread.main(ActivityThread.java:5221) 
      at java.lang.reflect.Method.invoke(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:372) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694) 

Answer 1

public static final int SERVICES_ALL = 1; 
public static final int SERVICES_FEATURED = 2; 
public static final int SERVICES_NEW = 3; 

sollte 0-Basis-index,

public static final int SERVICES_ALL = 0; 
public static final int SERVICES_FEATURED = 1; 
public static final int SERVICES_NEW = 2; 

getItem ist, was bedeutet, dass in Ihr Code, der case 0 Ihres Adapters passt nie zu eins, und in diesem Fall geben Sie ein Null-Fragment zurück, das die Ausnahme verursacht