自定义SetAdapter在Fragment Activity中返回nullpointerexception

时间：2015-07-20 19:58:31

标签： java android android-fragments nullpointerexception fragment

我有一个带有customAdapter的Fragment Activity，但是setAdapter给我一个nullpointerexception。 在CustomAdapter中，我返回一个ParseQuery。 我无法将Fragment扩展到ListFragment，因为标签停止工作。 请帮我找到错误。

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)

1 个答案:

答案 0 :(得分：0)

您需要从片段中的膨胀视图中获取ListView：

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;

}

还要确保将urgentTodosAdapter声明为实例变量：

public class FragmentFichas extends Fragment {

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