Unable to start Activity Android

Question

I've got a NPE when I try to launch this activity. This activity is working fine until I try to add a navigation drawer. I didn't manage to find how to get this work together. I put bellow my Oncreate method. This activity shows a list view with Json parsing and a drawer menu to access to other activities.

My code:

public class FavoritesActivity 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;

private ProgressDialog pDialog;

private static String mylat;
private static String mylng;

// URL to get JSON

private static String url2 = "http://apiurl";

// JSON Node names
private static final String TAG_NAME = "shop_name";
private static final String TAG_ADDRESS_STRING = "shop_address";
private static final String TAG_URL = "shop_url";
private static final String TAG_BOOKLET_URL = "feuilletez";
TextView shop_address;
TextView shop_name;
TextView shop_url;
private LocationManager locMan;
ImageButton feuilletez;
private ListView list;

private String latitude;
private String longitude;


ArrayList<String>shoplatitude;
ArrayList<String>shoplongitude;
ArrayList<String>shopname;
ArrayList<String>shopaddress;
ArrayList<String>shopurl;

// Hashmap for ListView
ArrayList<HashMap<String, String>> oslist = new ArrayList<HashMap<String, String>>();

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


    setContentView(R.layout.activity_favorites);

    mTitle = mDrawerTitle = getTitle();

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

    // nav drawer icons from resources
    navMenuIcons = getResources()
            .obtainTypedArray(R.array.nav_drawer_icons);

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

    navDrawerItems = new ArrayList<NavDrawerItem>();

    // adding nav drawer items to array
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[5], navMenuIcons.getResourceId(5, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[6], navMenuIcons.getResourceId(6, -1), true, "3"));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[7], navMenuIcons.getResourceId(7, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[8], navMenuIcons.getResourceId(8, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[9], navMenuIcons.getResourceId(9, -1)));


    // Recycle the typed array
    navMenuIcons.recycle();

    mDrawerList.setOnItemClickListener(new SlideMenuClickListener());

    // 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);

    // Calling async task to get json
    new GetJson().execute();

    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(1);
    }
}

/**
 * Slide menu item click listener
 * */
public class SlideMenuClickListener implements
        ListView.OnItemClickListener {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,
            long id) {
        // display view for selected nav drawer item
        displayView(position);

    }





}

/**
 * Async task class to get json by making HTTP call
 * */
private class GetJson extends AsyncTask<Void, Void, Void> {

...

Logcat:

01-29 10:00:29.573: E/AndroidRuntime(6923): FATAL EXCEPTION: main
01-29 10:00:29.573: E/AndroidRuntime(6923): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.begital.vitalis/com.begital.vitalis.FavoritesActivity}: java.lang.NullPointerException
01-29 10:00:29.573: E/AndroidRuntime(6923):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at android.app.ActivityThread.access$600(ActivityThread.java:130)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at android.os.Looper.loop(Looper.java:137)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at android.app.ActivityThread.main(ActivityThread.java:4745)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at java.lang.reflect.Method.invokeNative(Native Method)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at java.lang.reflect.Method.invoke(Method.java:511)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at dalvik.system.NativeStart.main(Native Method)
01-29 10:00:29.573: E/AndroidRuntime(6923): Caused by: java.lang.NullPointerException
01-29 10:00:29.573: E/AndroidRuntime(6923):     at com.begital.vitalis.FavoritesActivity.onCreate(FavoritesActivity.java:145)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at android.app.Activity.performCreate(Activity.java:5008)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
01-29 10:00:29.573: E/AndroidRuntime(6923):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
01-29 10:00:29.573: E/AndroidRuntime(6923):     ... 11 more

Answer 1

Declare your

mDrawerList.setOnItemClickListener(new SlideMenuClickListener());

after

mDrawerList.setAdapter(adapter);

like this :

mDrawerList.setAdapter(adapter);
mDrawerList.setOnItemClickListener(new SlideMenuClickListener());

do not declare the onItemClick before setAdapter.