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POKeep getting NullPointerExceptions when attempting to call getWritableDatabase()
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  1. POKeep getting NullPointerExceptions when attempting to call getWritableDatabase()
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    copied!<p>I'm new to the Android framework and I can't get past first base with SQLite.</p> <p>I'm trying to build a very simple application that has a EditText search box, which when a key is pressed performs a Like %word% search on a SQLite database for for the text entered in the EditText box, and displays the results in a ListView.</p> <p>N.B. the below code included debugging and commented code, sorry I haven't got round to cleaning it up yet.</p> <p>The Activate is</p> <pre><code>public class sustainable_fish extends Activity { private String keycodeToAscii(int arg2){ String retvar = ""; switch(arg2){ case KeyEvent.KEYCODE_A: retvar = "a";break; case KeyEvent.KEYCODE_B: retvar = "b";break; </code></pre> <p>snipped, but you get the idea.</p> <pre><code> case KeyEvent.KEYCODE_RIGHT_BRACKET: retvar = ")";break; default: retvar = ""; break; }; return retvar; } Context that = getApplicationContext(); fishDB dh = new fishDB(getApplicationContext()); private OnKeyListener search = new OnKeyListener() { public boolean onKey(View arg0, int arg1, KeyEvent arg2) { @SuppressWarnings("unused") Cursor cur = null; String searchData; EditText myEditText = (EditText) findViewById(R.id.fish_search); CharSequence edit_text_value = myEditText.getText(); searchData = edit_text_value.toString(); searchData = searchData + keycodeToAscii(arg2.getKeyCode() ); Log.d("onKey", "searchData = "+searchData); /* Commented out because as the database doesn't work, so theirs no point just yet searching. cur = fish.search(searchData); if (cur != null) { String[] displayFields = new String[] {cur.getString(2), cur.getString(1)}; int[] displayViews = new int[] { R.id.fish_rank, R.id.fish_name}; SimpleCursorAdapter adapter = new SimpleCursorAdapter(that, R.layout.text_list, cur, displayFields, displayViews); ListView myList=(ListView)findViewById(android.R.id.list); myList.setAdapter(adapter); } */ return false; } }; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); EditText searchBar = (EditText) findViewById(R.id.fish_search); searchBar.setOnKeyListener(search); } } </code></pre> <p>The SQLite database is handled by fishDB</p> <pre><code> public class fishDB { public static final String DATABASE_NAME = "fish.db3"; public static final int DATABASE_VERSION = 1; private SQLiteDatabase database; private Context myContext; private static boolean booFirstrun = false; fishDB(Context inContext){ myContext = inContext; OpenHelper helper = new OpenHelper(myContext); Log.w("fishDB", "Called OpenHelper"); // Here be the problem... database = helper.getWritableDatabase(); } public boolean firstRun(){ return booFirstrun; } private static class OpenHelper extends SQLiteOpenHelper { private static final String CREATE_TABLE_FEEDS = "create table feeds (feed_id integer primary key autoincrement, " + "title text not null, url text not null);"; OpenHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); Log.w("OpenHelper", "Called superconstructor"); } @Override public void onCreate(SQLiteDatabase db) { try { Log.w("OpenHelper", "in onCreate"); booFirstrun = true; Log.w("OpenHelper", "set booFirstrun"); db.beginTransaction(); Log.w("OpenHelper", "db.beginTransaction"); try { // Create tables and test data db.execSQL(CREATE_TABLE_FEEDS); Log.w("OpenHelper", "execSQL"); db.setTransactionSuccessful(); Log.w("OpenHelper", "setTransactionSuccessful"); } catch (SQLException e) { Log.e("Error creating tables and debug data", e.toString()); throw e; } finally { db.endTransaction(); } } catch (Exception e) { Log.e("OpenHelper", e.toString() ); } finally { Log.w("OpenHelper", "out of onCreate"); } } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { Log.w("OpenHelper", "Upgrading database, this will drop tables and recreate."); onCreate(db); } } } </code></pre> <p>Now every time "database = helper.getWritableDatabase();" is called the app crashes with a NullPointerException. I've managed to trace the error to the onCreate method of OpenHelper and the "db.beginTransaction();" line.</p> <p>What am I missing?</p>
 

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