自定義SetAdapter在片段活動中返回nullpointerexception

-2

我有一個帶有customAdapter的片段活動，但setAdapter向我返回一個nullpointerexception。在CustomAdapter中，我返回一個ParseQuery。我無法將Fragment擴展到ListFragment，因爲Tab停止工作。請幫我看看這個錯誤。自定義SetAdapter在片段活動中返回nullpointerexception

MainActivity.java

package com.comunadigital.cuidatemasmaterial; 

import android.app.ListFragment; 
import android.content.Intent; 
import android.graphics.drawable.Drawable; 
import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentActivity; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentPagerAdapter; 
import android.support.v4.app.FragmentStatePagerAdapter; 
import android.support.v4.app.FragmentTabHost; 
import android.support.v4.view.ViewPager; 
import android.support.v7.app.ActionBarActivity; 
import android.os.Bundle; 
import android.support.v7.widget.Toolbar; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.ViewGroup; 
import android.widget.ProgressBar; 
import android.widget.Toast; 

import com.comunadigital.cuidatemasmaterial.fragments.FragmentDirectorio; 
import com.comunadigital.cuidatemasmaterial.fragments.FragmentFichas; 
import com.comunadigital.cuidatemasmaterial.fragments.FragmentForo; 
import com.comunadigital.cuidatemasmaterial.fragments.FragmentMedicinas; 
import com.parse.GetCallback; 
import com.parse.ParseACL; 
import com.parse.ParseException; 
import com.parse.ParseObject; 
import com.parse.ParseQuery; 
import com.parse.ParseUser; 
import com.parse.SaveCallback; 

import it.neokree.materialtabs.MaterialTab; 
import it.neokree.materialtabs.MaterialTabHost; 
import it.neokree.materialtabs.MaterialTabListener; 


public class MainActivity extends ActionBarActivity implements MaterialTabListener { 

    public static final String TAG = MainActivity.class.getSimpleName(); 
    protected ProgressBar mProgressBar; 


    //int representing our 0th tab corresponding to the Fragment where search results are dispalyed 
    public static final int TAB_FICHAS = 0; 
    //int corresponding to our 1st tab corresponding to the Fragment where box office hits are dispalyed 
    public static final int TAB_DIRECTORIO = 1; 
    //int corresponding to our 2nd tab corresponding to the Fragment where upcoming movies are displayed 
    public static final int TAB_MEDICINAS = 2; 
    // int corresponde al cuarto tab 
    public static final int TAB_FORO = 3; 

    //int corresponding to the number of tabs in our Activity 
    public static final int TAB_COUNT = 4; 


    private Toolbar mToolbar; 

    private ViewGroup mContainerToolbar; 
    private MaterialTabHost mTabHost; 
    private ViewPager mPager; 
    private ViewPagerAdapter mAdapter; 
    //private FragmentDrawer mDrawerFragment; 



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

     setupTabs(); 
     setupDrawer(); 


    } 

    private void setupDrawer() { 
     mToolbar = (Toolbar) findViewById(R.id.app_bar); 
     mContainerToolbar = (ViewGroup) findViewById(R.id.container_app_bar); 
     //set the Toolbar as ActionBar 
     setSupportActionBar(mToolbar); 

     mToolbar.setNavigationIcon(R.drawable.iconbar); 

     try{ 
      getSupportActionBar().setDisplayShowHomeEnabled(true); 
     }catch(NullPointerException e){ 
      e.printStackTrace(); 
     } 

    } 


    private void setupTabs() { 
     mTabHost = (MaterialTabHost) findViewById(R.id.materialTabHost); 
     mPager = (ViewPager) findViewById(R.id.viewPager); 
     mAdapter = new ViewPagerAdapter(getSupportFragmentManager()); 
     mPager.setAdapter(mAdapter); 
     //when the page changes in the ViewPager, update the Tabs accordingly 

     mPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() { 
      @Override 
      public void onPageSelected(int position) { 
       mTabHost.setSelectedNavigationItem(position); 

      } 
     }); 

     //Add all the Tabs to the TabHost 
     for (int i = 0; i < mAdapter.getCount(); i++) { 
      mTabHost.addTab(
        mTabHost.newTab() 
          .setIcon(mAdapter.getIcon(i)) 
          .setTabListener(this)); 
     } 
    } 



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

    @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.logoutButton) { 
      /* 
      * Log current user out using ParseUser.logOut() 
      */ 
      ParseUser.logOut(); 
      Intent intent = new Intent(this, Login.class); 
      intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK); 
      startActivity(intent); 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 

    @Override 
    public void onTabSelected(MaterialTab materialTab) { 
     //when a Tab is selected, update the ViewPager to reflect the changes 
     mPager.setCurrentItem(materialTab.getPosition()); 
    } 

    @Override 
    public void onTabReselected(MaterialTab materialTab) { 
    } 

    @Override 
    public void onTabUnselected(MaterialTab materialTab) { 
    } 


    //FragmentStatePagerAdapter 

    private class ViewPagerAdapter extends FragmentStatePagerAdapter { 

     //AQUI PONEMOS LOS ICONOS GRAFICOS 
     int icons[] = {R.drawable.ficha, 
       R.drawable.doctor, 
       R.drawable.medicina, 
       R.drawable.foro}; 

     FragmentManager fragmentManager; 

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


     @Override 
     public Fragment getItem(int num) { 
      Fragment fragment = null; 
//   L.m("getItem called for " + num); 
      switch (num) { 
       case TAB_FICHAS: 
        fragment = FragmentFichas.newInstance(getApplicationContext()); 
        break; 
       case TAB_DIRECTORIO: 
        fragment = FragmentDirectorio.newInstance(); 
        break; 
       case TAB_MEDICINAS: 
        fragment = FragmentMedicinas.newInstance(); 
        break; 
       case TAB_FORO: 
        fragment = FragmentForo.newInstance(); 
        break; 
      } 
      return fragment; 

     } 

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

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

     private Drawable getIcon(int position) { 
      return getResources().getDrawable(icons[position]); 
     } 
    } 
}

FragmentFichas.java

package com.comunadigital.cuidatemasmaterial.fragments; 


import android.app.ListFragment; 
import android.app.ProgressDialog; 
import android.content.Context; 
import android.content.Intent; 
import android.media.Image; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentActivity; 
import android.util.Log; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.AdapterView; 
import android.widget.ArrayAdapter; 
import android.widget.ListView; 

import com.comunadigital.cuidatemasmaterial.DoctoresActivity; 
import com.comunadigital.cuidatemasmaterial.MainActivity; 
import com.comunadigital.cuidatemasmaterial.R; 
import com.comunadigital.cuidatemasmaterial.adapters.CustomAdapter; 
import com.parse.FindCallback; 
import com.parse.ParseException; 
import com.parse.ParseObject; 
import com.parse.ParseQuery; 
import com.parse.ParseQueryAdapter; 
import com.parse.ParseUser; 

import java.util.List; 


/** 
* A simple {@link Fragment} subclass. 
* Use the {@link FragmentFichas#newInstance} factory method to 
* create an instance of this fragment. 
*/ 
public class FragmentFichas extends Fragment { 

    private static Context mContext; 
    private ParseQueryAdapter<ParseObject> mainAdapter; 

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

    public static FragmentFichas newInstance(Context context) { 
     mContext = context; 
     return new FragmentFichas(); 
    } 

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

     ListView mList = (ListView) getActivity().findViewById(R.id.list); 
     CustomAdapter urgentTodosAdapter = new CustomAdapter(getActivity()); 
     mList.setAdapter(urgentTodosAdapter); 
     urgentTodosAdapter.loadObjects(); 

    } 

    @Override 
    public void onResume() { 
     super.onResume(); 
     //urgentTodosAdapter.loadObjects(); 
    } 

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

     View view = inflater.inflate(R.layout.fragment_fichas, container, false); 

     /* 
     mList = (ListView) getActivity().findViewById(R.id.list); 
     urgentTodosAdapter = new CustomAdapter(container.getContext()); 
     mList.setAdapter(urgentTodosAdapter); 
     urgentTodosAdapter.loadObjects(); 
     */ 

     return view; 

    } 

}

CustomAdapter.java

package com.comunadigital.cuidatemasmaterial.adapters; 

import android.content.Context; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.TextView; 

import com.parse.ParseFile; 
import com.parse.ParseImageView; 
import com.parse.ParseObject; 
import com.parse.ParseQuery; 
import com.parse.ParseQueryAdapter; 
import com.parse.ParseUser; 

import com.comunadigital.cuidatemasmaterial.R; 

/** 
* Created by proyectos1 on 15/07/2015. 
*/ 
public class CustomAdapter extends ParseQueryAdapter<ParseObject> { 

    public CustomAdapter(Context context) { 
     // Use the QueryFactory to construct a PQA that will only show 
     // Todos marked as high-pri 
     super(context, new ParseQueryAdapter.QueryFactory<ParseObject>() { 
      public ParseQuery<ParseObject> create() { 
       ParseQuery query = new ParseQuery("FichasMedicas"); 
       query.whereEqualTo("user", ParseUser.getCurrentUser()); 
       return query; 
      } 
     }); 
    } 

    // Customize the layout by overriding getItemView 
    @Override 
    public View getItemView(ParseObject object, View v, ViewGroup parent) { 
     if (v == null) { 
      v = View.inflate(getContext(), R.layout.urgent_item, null); 
     } 

     super.getItemView(object, v, parent); 

     // Add and download the image 
     ParseImageView todoImage = (ParseImageView) v.findViewById(R.id.icon); 
     ParseFile imageFile = object.getParseFile("foto"); 
     if (imageFile != null) { 
      todoImage.setParseFile(imageFile); 
      todoImage.loadInBackground(); 
     } 

     // Add the title view 
     TextView titleTextView = (TextView) v.findViewById(R.id.text1); 
     titleTextView.setText(object.getString("nombre")); 

     // Add a reminder of how long this item has been outstanding 
     //TextView timestampView = (TextView) v.findViewById(R.id.timestamp); 
     //timestampView.setText(object.getCreatedAt().toString()); 

     return v; 
    } 

}

ActivityMain.xml

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:id="@+id/drawer_layout" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:orientation="vertical"> 

     <LinearLayout 
      android:id="@+id/container_app_bar" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:orientation="vertical"> 

      <include 
       android:id="@+id/app_bar" 
       layout="@layout/app_bar" /> 

      <it.neokree.materialtabs.MaterialTabHost 
       android:id="@+id/materialTabHost" 
       android:layout_width="match_parent" 
       android:layout_height="48dp" 
       android:layout_below="@+id/app_bar" 
       app:accentColor="@color/colorAccent" 
       app:hasIcons="true" 
       app:iconColor="@android:color/white" 
       app:primaryColor="@color/colorPrimary" /> 
     </LinearLayout> 


     <android.support.v4.view.ViewPager 
      android:id="@+id/viewPager" 
      android:layout_width="match_parent" 
      android:layout_height="0dp" 
      android:layout_below="@+id/materialTabHost" 
      android:layout_weight="1" /> 
    </LinearLayout> 

</android.support.v4.widget.DrawerLayout>

FragmentFichas.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical"> 

    <!-- TODO: Update blank fragment layout --> 

    <ListView 
     android:id="@+id/list" 
     android:layout_width="fill_parent" 
     android:layout_height="fill_parent" /> 

</LinearLayout>

LOGERROR

07-20 15:46:45.375 9596-9596/com.comunadigital.cuidatemasmaterial E/AndroidRuntime﹕ FATAL EXCEPTION: main 
    Process: com.comunadigital.cuidatemasmaterial, PID: 9596 
    java.lang.NullPointerException 
      at com.comunadigital.cuidatemasmaterial.fragments.FragmentFichas.onCreate(FragmentFichas.java:59) 
      at android.support.v4.app.Fragment.performCreate(Fragment.java:1766) 
      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:917) 
      at android.support.v4.app.FragmentManagerImpl.performPendingDeferredStart(FragmentManager.java:846) 
      at android.support.v4.app.Fragment.setUserVisibleHint(Fragment.java:860) 
      at android.support.v4.app.FragmentStatePagerAdapter.setPrimaryItem(FragmentStatePagerAdapter.java:152) 
      at android.support.v4.view.ViewPager.populate(ViewPager.java:1103) 
      at android.support.v4.view.ViewPager.populate(ViewPager.java:951) 
      at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1473) 
      at android.view.View.measure(View.java:16497) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:847) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
      at android.view.View.measure(View.java:16497) 
      at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:868) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
      at android.support.v7.internal.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:124) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:695) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:695) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
      at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1912) 
      at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1109) 
      at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1291) 
      at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996) 
      at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600) 
      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761) 
      at android.view.Choreographer.doCallbacks(Choreographer.java:574) 
      at android.view.Choreographer.doFrame(Choreographer.java:544) 
      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747) 
      at android.os.Handler.handleCallback(Handler.java:733) 
      at android.os.Handler.dispatchMessage(Handler.java:95) 
      at android.os.Looper.loop(Looper.java:136) 
      at android.app.ActivityThread.main(ActivityThread.java:5001) 
      at java.lang.reflect.Method.invokeNative(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:515) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601) 
      at dalvik.system.NativeStart.main(Native Method)

來源

2015-07-20 Miguel Angel Rodriguez

您需要從充氣查看得到的ListView的片段：

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

    View view = inflater.inflate(R.layout.fragment_fichas, container, false); 


    //It's not in the Activity layout: 
    //mList = (ListView) getActivity().findViewById(R.id.list); 

    //It's in the Fragment layout: 
    mList = (ListView) view.findViewById(R.id.list); 

    urgentTodosAdapter = new CustomAdapter(getActivity()); 
    mList.setAdapter(urgentTodosAdapter); 
    urgentTodosAdapter.loadObjects(); 


    return view; 

}

此外，一定要聲明urgentTodosAdapter作爲一個實例變量：

public class FragmentFichas extends Fragment { 

    private static Context mContext; 
    private ParseQueryAdapter<ParseObject> mainAdapter; 
    private CustomAdapter urgentTodosAdapter; //added 
    //.............

來源

2015-07-20 20:31:38

謝謝，效果很好！ –

自定義SetAdapter在片段活動中返回nullpointerexception

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