“插入单词”不会将单词添加到数据库中

Question

在我的应用程序中，当我转到名为“编辑单词”的屏幕，然后转到“添加单词”时 当我输入一个单词时，它不会被添加到我的database中。 我认为问题出在我的“ DBHelper”中的“插入单词”中。

非常感谢您的帮助。

public class DBHelper extends SQLiteOpenHelper {

    public static final String DATABASE_NAME = "MyDBName.db";
    public static final String WORDS_TABLE_NAME = "words";
    public static final String WORDS_COLUMN_ID = "id";
    public static final String WORDS_COLUMN_NAME = "word";

    public DBHelper(Context context) {

        super(context, DATABASE_NAME , null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        db.execSQL(
                "create table words " +
                        "(id integer primary key, word text)"
        );
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
    {
        // TODO Auto-generated method stub
        db.execSQL("DROP TABLE IF EXISTS words");
        onCreate(db);
    }

    public boolean insertWord (String word) {

        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put("word", word);
        db.insert("words", null, contentValues);
        return true;
    }

/*        public Cursor getData(int id) {
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor res =  db.rawQuery( "select * from words where id="+id+"", 
        null );
        return res;
    }
*/
    public int numberOfRows(){
        SQLiteDatabase db = this.getReadableDatabase();
        int numRows = (int) DatabaseUtils.queryNumEntries(db, 
        WORDS_TABLE_NAME);
        return numRows;
    }

    public Integer deleteWord (String word) {
        SQLiteDatabase db = this.getWritableDatabase();
        return db.delete("words",
                "word = ? ",
                new String[] { word });
    }

    public Integer deleteWord (Integer id) {
        SQLiteDatabase db = this.getWritableDatabase();
        return db.delete("words",
                "id = ? ",
                new String[] { Integer.toString(id) });
    }

    public String getRandomWord() {
        int id = (int)(Math.random())*(numberOfRows())+1;
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor res =  db.rawQuery( "select word from words where id="+id+"", 
        null );
        String s = "";
        if (res.moveToFirst())
            s = res.getString(res.getColumnIndex("word"));
        res.close();
        return s;
    }
/*
    public ArrayList<String> getAllWords() {
        ArrayList<String> array_list = new ArrayList<String>();

        //hp = new HashMap();
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor res =  db.rawQuery( "select * from words", null );
        res.moveToFirst();

        while(res.isAfterLast() == false){

       array_list.add(res.getString(res.getColumnIndex(WORDS_COLUMN_NAME)));
            res.moveToNext();
        }
        return array_list;
    }*/
}