Navigation Drawer FC at Adapter

Question

I am following a guide for a Navigation Drawer implementation. Theguide has icons for each item in the navigation drawer and I am editing it so that it does not have icons for each item. Asa result I broke something and now it FC's at the adapter. The error I am getting is:

02-13 02:31:29.577    3921-3921/com.beerportfolio.beerportfoliopro E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.beerportfolio.beerportfoliopro/com.beerportfolio.beerportfoliopro.MainDrawer2}: java.lang.NullPointerException
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2517)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2574)
            at android.app.ActivityThread.access$600(ActivityThread.java:162)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1413)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:158)
            at android.app.ActivityThread.main(ActivityThread.java:5789)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:843)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.NullPointerException
            at com.beerportfolio.beerportfoliopro.MainDrawer2.onCreate(MainDrawer2.java:71)
            at android.app.Activity.performCreate(Activity.java:5195)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1111)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2473)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2574)
            at android.app.ActivityThread.access$600(ActivityThread.java:162)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1413)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:158)
            at android.app.ActivityThread.main(ActivityThread.java:5789)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:843)
            at dalvik.system.NativeStart.main(Native Method)

MY MainDrawer2 code is:

public class MainDrawer2 extends Activity {

    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mDrawerToggle;

    // nav drawer title
    private CharSequence mDrawerTitle;

    // used to store app title
    private CharSequence mTitle;

    // slide menu items
    private String[] navMenuTitles;
    private TypedArray navMenuIcons;

    private ArrayList<NavDrawerItem> navDrawerItems;
    private NavDrawerListAdapter adapter;

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

        mTitle = mDrawerTitle = getTitle();

        // load slide menu items
        navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);

        // nav drawer icons from resources


        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        mDrawerList = (ListView) findViewById(R.id.drawer);

        navDrawerItems = new ArrayList<NavDrawerItem>();

        // adding nav drawer items to array
        // Home
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[0]));
        // Find People
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[1]));


        // setting the nav drawer list adapter
        adapter = new NavDrawerListAdapter(getApplicationContext(),
                navDrawerItems);
        mDrawerList.setAdapter(adapter);

        // enabling action bar app icon and behaving it as toggle button
        getActionBar().setDisplayHomeAsUpEnabled(true);


        //getActionBar().setHomeButtonEnabled(true);

        mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
                R.drawable.ic_drawer, //nav menu toggle icon
                R.string.app_name, // nav drawer open - description for accessibility
                R.string.app_name // nav drawer close - description for accessibility
        ){
            public void onDrawerClosed(View view) {
                getActionBar().setTitle(mTitle);
                // calling onPrepareOptionsMenu() to show action bar icons
                invalidateOptionsMenu();
            }

            public void onDrawerOpened(View drawerView) {
                getActionBar().setTitle(mDrawerTitle);
                // calling onPrepareOptionsMenu() to hide action bar icons
                invalidateOptionsMenu();
            }
        };
        mDrawerLayout.setDrawerListener(mDrawerToggle);

        if (savedInstanceState == null) {
            // on first time display view for first nav item
            displayView(0);
        }
    }

    /**
     * Diplaying fragment view for selected nav drawer list item
     * */
    private void displayView(int position) {
        // update the main content by replacing fragments
        Fragment fragment = null;
        switch (position) {
            case 0:
                fragment = new StatisticsPage();
                break;
            case 1:
                fragment = new Discover();
                break;

            default:
                break;
        }

        if (fragment != null) {
            FragmentManager fragmentManager = getFragmentManager();
            fragmentManager.beginTransaction()
                    .replace(R.id.main, fragment).commit();

            // update selected item and title, then close the drawer
            mDrawerList.setItemChecked(position, true);
            mDrawerList.setSelection(position);
            setTitle(navMenuTitles[position]);
            mDrawerLayout.closeDrawer(mDrawerList);
        } else {
            // error in creating fragment
            Log.e("MainActivity", "Error in creating fragment");
        }
    }


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

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // toggle nav drawer on selecting action bar app icon/title
        if (mDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }
        // Handle action bar actions click
        switch (item.getItemId()) {
            case R.id.action_settings:
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

    /***
     * Called when invalidateOptionsMenu() is triggered
     */
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // if nav drawer is opened, hide the action items
        boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
        menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
        return super.onPrepareOptionsMenu(menu);
    }

    @Override
    public void setTitle(CharSequence title) {
        mTitle = title;
        getActionBar().setTitle(mTitle);
    }

    /**
     * When using the ActionBarDrawerToggle, you must call it during
     * onPostCreate() and onConfigurationChanged()...
     */

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        // Sync the toggle state after onRestoreInstanceState has occurred.
        mDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        // Pass any configuration change to the drawer toggls
        mDrawerToggle.onConfigurationChanged(newConfig);
    }
}

NavDrawerListAdapter is:

public class NavDrawerListAdapter extends BaseAdapter {

    private Context context;
    private ArrayList<NavDrawerItem> navDrawerItems;

    public NavDrawerListAdapter(Context context, ArrayList<NavDrawerItem> navDrawerItems){
        this.context = context;
        this.navDrawerItems = navDrawerItems;
    }

    @Override
    public int getCount() {
        return navDrawerItems.size();
    }

    @Override
    public Object getItem(int position) {
        return navDrawerItems.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            LayoutInflater mInflater = (LayoutInflater)
                    context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
            convertView = mInflater.inflate(R.layout.drawer_list_item, null);
        }


        TextView txtTitle = (TextView) convertView.findViewById(R.id.title);

        txtTitle.setText(navDrawerItems.get(position).getTitle());

        // displaying count
        // check whether it set visible or not
        if(navDrawerItems.get(position).getCounterVisibility()){
            //txtCount.setText(navDrawerItems.get(position).getCount());
        }else{
            // hide the counter view
            //txtCount.setVisibility(View.GONE);
        }

        return convertView;
    }

}

NavDrawerItem is:

public class NavDrawerItem {

    private String title;
    private int icon;
    private String count = "0";
    // boolean to set visiblity of the counter
    private boolean isCounterVisible = false;

    public NavDrawerItem(){}

    public NavDrawerItem(String title){
        this.title = title;
    }

    public NavDrawerItem(String title, int icon, boolean isCounterVisible){
        this.title = title;
        this.isCounterVisible = isCounterVisible;
        this.count = count;
    }

    public String getTitle(){
        return this.title;
    }

    public int getIcon(){
        return this.icon;
    }

    public String getCount(){
        return this.count;
    }

    public boolean getCounterVisibility(){
        return this.isCounterVisible;
    }

    public void setTitle(String title){
        this.title = title;
    }

    public void setIcon(int icon){
        this.icon = icon;
    }

    public void setCount(String count){
        this.count = count;
    }

    public void setCounterVisibility(boolean isCounterVisible){
        this.isCounterVisible = isCounterVisible;
    }
}

Update:

Line 71 is this:

mDrawerList.setAdapter(adapter);

Answer 1

Double check your layout file, looks like the reference to the ListView is coming back null.