Unable to start component activity Component Info Null Pointer Exception

Question

I'm not sure how to find the line number in the Logcat output. Also, with this latest Android Studio version, the regular logcat doesn't work, so I have to start the Android Device Monitor to get a look at it. And I can only snag a png, so sincere apologies for that.

Here's the MainActivity class:

public class MainActivity extends Activity {

ListView listView;

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

    listView = (ListView) findViewById(R.id.listViewCategories);
    String[] categories = getResources().getStringArray(R.array.categories_array);

    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, categories);

    listView.setAdapter(adapter);
    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            // ListView Clicked item index
            int itemPosition = position;
            // ListView Clicked item value
            String itemValue = (String) listView.getItemAtPosition(position);
            // Show Alert
            /*Toast.makeText(getApplicationContext(),
                    "Position: " + itemPosition + "  List Item: " + itemValue,
                    Toast.LENGTH_LONG)
                    .show();*/
            Intent intent = new Intent(MainActivity.this, DisplayResult.class);
            intent.putExtra("ITEMVALUE", itemValue);
            startActivity(intent);
        }


    });
}

}

Here's the second activity, DisplayResult:

public class DisplayResult extends Activity {

String selectedCategory;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.verses);

    Bundle b = getIntent().getExtras();
    String selectedCategory = b.getString("ITEMVALUE");

    //Toast.makeText(DisplayResult.this, "Category passed: " + selectedCategory,
    // Toast.LENGTH_LONG).show();

    final ListView lv = (ListView) findViewById(R.id.listViewItems);
    ArrayList<Promise> results = null;
    lv.setAdapter(new MyCustomArrayAdapter(this, results));
} // end onCreate

public ArrayList<Promise> GetPromises() {
    String table = "promises";
    ArrayList<Promise> promises = new ArrayList<Promise>();
    Promise prms = new Promise();
    SQLiteDatabase newDB;
    //SQLiteDatabase db = MyDBHandler.getReadableDatabase();

    //ArrayList<Promise> results = null;
    ArrayList<Promise> results = new ArrayList<Promise>();

    try {
        MyDBHandler dbHandler = new MyDBHandler(this.getApplicationContext());
        newDB = dbHandler.getReadableDatabase();
        Cursor c = newDB.rawQuery("SELECT * FROM " + MyDBHandler.TABLE_NAME +
                " WHERE KEY_CATEGORY = ?", new String[]{selectedCategory});

        if (c != null) {
            if (c.moveToFirst()) {
                do {
                    String category = c.getString(c.getColumnIndex("KEY_CATEGORY"));
                    String book = c.getString(c.getColumnIndex("KEY_BOOK"));
                    String chapter = c.getString(c.getColumnIndex("KEY_CHAPTER"));
                    String verse = c.getString(c.getColumnIndex("KEY_VERSE"));
                    String word = c.getString(c.getColumnIndex("KEY_WORD"));
                    Promise promise = new Promise();
                    /*promise.add(Strings)
                    results.add(promise)*/
                    results.add(new Promise(category, book, chapter, verse, word));
                } while (c.moveToNext());
            } // end inner if
        } // end outer if
    } catch (SQLiteException se) {
        Log.e(getClass().getSimpleName(), "Could not create or open the database");
    } finally {

    }
    return results;
}

}

Here's the DBHandler class:

public class MyDBHandler extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "promisesdatabase.sqlite";

public static final String TABLE_NAME = "promises";

public static final String KEY_ROWID = "id";
public static final String KEY_CATEGORY = "category";
public static final String KEY_BOOK = "book";
public static final String KEY_CHAPTER = "chapter";
public static final String KEY_VERSE = "verse";
public static final String KEY_WORD = "word";

public MyDBHandler(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
     String DATABASE_CREATE =
            "CREATE TABLE if not exists " + TABLE_NAME + " (" +
                    KEY_ROWID + "integer PRIMARY KEY," +
                    KEY_CATEGORY + " TEXT," +
                    KEY_BOOK + " TEXT," +
                    KEY_CHAPTER + " TEXT," +
                    KEY_VERSE + " TEXT," +
                    KEY_WORD + " TEXT" + ")";

     db.execSQL(DATABASE_CREATE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
    onCreate(db);
}

Here's the CustomArrayAdapter class:

public class MyCustomArrayAdapter extends ArrayAdapter {

private static ArrayList<Promise> promiseArrayList;

private LayoutInflater mInflater;

public MyCustomArrayAdapter(Context context, ArrayList<Promise> results) {
    super(context, 0, results);
    promiseArrayList = results;
    mInflater = LayoutInflater.from(context);
}
public int getCount() {
    return promiseArrayList.size();
}
public Object getItem(int position) {
    return promiseArrayList.get(position);
}
public long getItemId(int position) {
    return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // Get the data item for this position
    // Promise Promise = getItem(position); took out due to other blog geekswithblogs
    // Check if an existing view is being reused, otherwise inflate the view
    ViewHolder holder; // view lookup cache stored in tag
    if (convertView == null) {
        convertView = mInflater.inflate(R.layout.verses, null);
        holder = new ViewHolder();
        //LayoutInflater inflater = LayoutInflater.from(getContext());
        //convertView = inflater.inflate(R.layout.verses, parent, false);
        holder.txtcategory = (TextView) convertView.findViewById(R.id.txtViewCategory);
        holder.txtbook = (TextView) convertView.findViewById(R.id.txtViewBook);
        holder.txtchapter = (TextView) convertView.findViewById(R.id.txtViewChapter);
        holder.txtverse = (TextView) convertView.findViewById(R.id.txtViewVerse);
        holder.txtword = (TextView) convertView.findViewById(R.id.txtViewWord);
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }
    // Populate the data into the template view using the data object
    holder.txtcategory.setText(promiseArrayList.get(position).getCategory());
    holder.txtbook.setText(promiseArrayList.get(position).getBook());
    holder.txtchapter.setText(promiseArrayList.get(position).getChapter());
    holder.txtverse.setText(promiseArrayList.get(position).getVerse());
    holder.txtword.setText(promiseArrayList.get(position).getWord());
    // Return the completed view to render on screen
    return convertView;
}
private static class ViewHolder {
    TextView id;
    TextView txtcategory;
    TextView txtbook;
    TextView txtchapter;
    TextView txtverse;
    TextView txtword;
}

There is also a Promise class (the data model) but I didn't think it necessary to post.

Here's the logcat png

Answer 1

I could be wrong, but should the line

ArrayList<Promise> results = null;

not read

ArrayList<Promise> results = GetPromises();

The issue seems to be that your ListView in DisplayResult is trying to display using the data from your MyCustomAdapter, which is being given null instead of a valid ArrayList of Promises.