Unable to launch app - java.lang.NullPointerException

Question

I'm having problems launching my app (crashes), while there is no errors in code. This happend after i converted code of List View activity to List Fragment...

My main activity:

package com.example.eronetmarket;

import com.preporuceno_app.AppAdapter;

import android.R.drawable;
import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;


public class MainActivity extends FragmentActivity implements ActionBar.TabListener {


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


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




        viewPager = (ViewPager) findViewById(R.id.pager);


        final ActionBar actionBar=getActionBar();

        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        actionBar.setDisplayShowTitleEnabled(false);
        actionBar.setBackgroundDrawable(new ColorDrawable(Color.RED));
        //actionBar.setDisplayShowHomeEnabled(false);

        addTabs(actionBar);
        viewPager.setAdapter(new MyAdapter(getSupportFragmentManager()));
        viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int i, float v, int i2) {
                Log.d("VIVZ","onPageScrolled "+i+" "+v+" "+i2);
            }

            @Override
            public void onPageSelected(int i) {
                actionBar.setSelectedNavigationItem(i);
                Log.d("VIVZ","onPageSelected "+i);
            }

            @Override
            public void onPageScrollStateChanged(int i) {
                if(i==ViewPager.SCROLL_STATE_IDLE)
                Log.d("VIVZ","onPageScrollStateChanged scroll state idle "+i);
                if(i==ViewPager.SCROLL_STATE_DRAGGING)
                    Log.d("VIVZ","onPageScrollStateChanged scroll state dragging "+i);
                if(i==ViewPager.SCROLL_STATE_SETTLING)
                    Log.d("VIVZ","onPageScrollStateChanged scroll state settling "+i);
            }
        });

        }

    private void addTabs(ActionBar actionBar)
    {
        ActionBar.Tab tab1=actionBar.newTab();
        tab1.setText("PREPORUČENO");
        tab1.setTabListener(this);

        ActionBar.Tab tab2=actionBar.newTab();
        tab2.setText("NAJPOPULARNIJE");
        tab2.setTabListener(this);

        ActionBar.Tab tab3=actionBar.newTab();
        tab3.setText("KATEGORIJE");
        tab3.setTabListener(this);

        actionBar.addTab(tab1);
        actionBar.addTab(tab2);
        actionBar.addTab(tab3);
    }

    @Override
    public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
        viewPager.setCurrentItem(tab.getPosition());
//        Log.d("VIVZ","onTabSelected "+tab.getText());
    }

    @Override
    public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
//        Log.d("VIVZ","onTabUnselected "+tab.getText());
    }

    @Override
    public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
//        Log.d("VIVZ","onTabReselected "+tab.getText());
    }


}

class MyAdapter extends FragmentStatePagerAdapter
{

    public MyAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int i) {
        Fragment fragment=null;
        if(i==0)
        {
            fragment=new FragmentA();
        }
        if(i==1)
        {
            fragment=new Preporuceno();
        }
        if(i==2)
        {
            fragment=new FragmentC();
        }
        return fragment;
    }

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

And my fragment list:

package com.example.eronetmarket;

import java.io.FileNotFoundException;

import android.content.Context;
import android.content.DialogInterface.OnClickListener;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.ListFragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;

public class Preporuceno extends ListFragment  {

    private AppAdapter mAdapter;
    private ListView siteList;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    Log.i("mobAppModel", "OnCreate()");    
    View rootView = inflater.inflate(R.layout.activity_preporuceno, container, false);

    siteList = (ListView) getActivity().findViewById(R.id.listView1);   

    siteList.setOnItemClickListener(new OnItemClickListener(){

        @Override
        public void onItemClick(AdapterView<?> parent, View v, int pos,long id) {
            String url = mAdapter.getItem(pos).getstoreURL();
            Intent i = new Intent(Intent.ACTION_VIEW);
            i.setData(Uri.parse(url));
            startActivity(i);

        }
    });

        if(isNetworkAvailable()){
            Log.i("mobAppModel", "starting download Task");
            AppDownloadTask download = new AppDownloadTask();
            download.execute();
        }else{
            mAdapter = new AppAdapter(getActivity().getApplicationContext(), -1, XMLsourcePullParser.getmobAppModel(getActivity()));
            siteList.setAdapter(mAdapter);
        }

        return rootView;
    }

    private boolean isNetworkAvailable() {
        ConnectivityManager connectivityManager 
              = (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
        return activeNetworkInfo != null && activeNetworkInfo.isConnected();
    } 
    private class AppDownloadTask extends AsyncTask<Void, Void, Void>{
        @Override
        protected Void doInBackground(Void... arg0) {
            //Download the file
            try {
                Downloader.DownloadFromUrl("http://minores.info/joomla30/stacksites.xml", getActivity().openFileOutput("XMLsource.xml", Context.MODE_PRIVATE));
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }

            return null;
        }
        @Override
        protected void onPostExecute(Void result){
            //setup our Adapter and set it to the ListView.
            mAdapter = new AppAdapter(getActivity().getApplicationContext(), -1, XMLsourcePullParser.getmobAppModel(getActivity()));
            siteList.setAdapter(mAdapter);
            Log.i("mobAppModel", "adapter size = "+ mAdapter.getCount());
        }

    }

 }

Here is my LogCat messages:

Logcat

In line 38 where LogCat shows error, I have this line public void onItemClick(AdapterView<?> parent, View v, int pos,long id) {

I don't understand where I went wrong?

Can you post the actual stack trace rather than a screenshot of it? The stack trace has line numbers telling you were the issue is. Did you look at that line in your code? — Stealth Rabbi, Jul 11 '14 at 16:19

Raghunandan · Accepted Answer · 2014-07-11T16:31:54.010

2

Change this

siteList = (ListView) getActivity().findViewById(R.id.listView1);

to

siteList = (ListView) rootView.findViewById(R.id.listView1);

The view belongs to the inflated layout and you need to use the view object to initialize views.

java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'

ListActivity or ListFragment will have listview which occuppies the entire screen. If you want to have other views in the layout then your layout must have listview with id andorid.R.id.list

http://developer.android.com/reference/android/app/ListFragment.html

QUoting docs

ListFragment has a default layout that consists of a single list view. However, if you desire, you can customize the fragment layout by returning your own view hierarchy from onCreateView(LayoutInflater, ViewGroup, Bundle). To do this, your view hierarchy must contain a ListView object with the id "@android:id/list" (or list if it's in code)

edited Jul 11 '14 at 16:31

answered Jul 11 '14 at 16:19

Raghunandan

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Thanks man, totally missed that.. But now new problem :\ --- java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list' – Drazen Jul 11 '14 at 16:27
@Drazen chekc the update. You actullay don't need to inflate a layout. just in onActivityCreated us `getListView()` or `setListAdapter(youradapter)` – Raghunandan Jul 11 '14 at 16:32
1

@Drazen you can actulla extend Fragment instead of ListFragment which is a easy fix. But do learn about ListFragment – Raghunandan Jul 11 '14 at 17:00

Unable to launch app - java.lang.NullPointerException

1 Answers1