SQLiteDatabase update not working?

Question

I am trying to get db.update to update one of the rows of my database with new values but it does not seem to be saving. I have looked over my syntax but I cannot seem to get the data to save. The insert function is working but not update. Any help would be appreciated. Below is my data class which uses a DbHelper object.

  public class Data {
    static final String TAG = "Data";

    public static final String DB_NAME = "data.db";
    public static final String TABLE_NAME = "tasks";
    public static final String C_ID = "_id";
    public static final String C_TASK = "taskname";
    public static final String C_DUE_DATE = "due_date";
    public static final String C_PRIORITY = "priority";
    public static final int DB_VERSION = 1;

    Context context;
    DbHelper dbHelper;
    SQLiteDatabase db;

    public Data(Context context) {
        this.context = context;
        dbHelper = new DbHelper();
    }

    public void insert(ToDoItem task) {
        db = dbHelper.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(C_TASK, task.getTask());
        values.put(C_PRIORITY, task.getPriority());

        db.insert(TABLE_NAME, null, values);
    }
    public void update(int id, ToDoItem task) {
    ContentValues values = new ContentValues();
    values.put(C_ID, id);
    values.put(C_TASK, task.getTask());
    values.put(C_PRIORITY, task.getPriority());

    String[] whereArgs = {String.valueOf(id)};

    db.update(TABLE_NAME, values, C_ID +" =?", whereArgs);
    System.out.println(db.update(TABLE_NAME, values, C_ID +" =?", whereArgs));

    Log.d(TAG, "updating task " + db.toString() +" "+ id + " to priority " + task.getPriority());
}

    public void delete(int id){
        db.delete(TABLE_NAME, C_ID+"="+id, null);
    }

    public Cursor queueAll(){
        db = dbHelper.getWritableDatabase();

        String[] columns = new String[]{C_ID, C_TASK, C_DUE_DATE, C_PRIORITY};

        Cursor cursor = db.query(TABLE_NAME, columns,   
                null, null, null, null, null);
        return cursor;
     }

    class DbHelper extends SQLiteOpenHelper {

        public DbHelper() {
            super(context, DB_NAME, null, DB_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            String sql = String.format("create table %s" +
                        "(%s int primary key, %s text, %s text, %s int)", 
                        TABLE_NAME, C_ID, C_TASK, C_DUE_DATE, C_PRIORITY);

            Log.d(TAG, "onCreate with SQL:"+sql);

            db.execSQL(sql);    
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            db.execSQL("drop if exists " + TABLE_NAME);
            onCreate(db);
        }
    }

}

Here is the ToDoItem object class I am trying to update the priority when an item is clicked

     public class ToDoItem {
        private String task;
        private String dueDate;
        private int priority;

        public ToDoItem(String task) {
        this.task = task;
        this.priority = 1;
    }

    public ToDoItem(String task, String dueDate) {
        this.task = task;
        this.dueDate = dueDate;
        this.priority = 1;
    }

    public ToDoItem(String task, int priority) {
        this.task = task;
        if(priority <=3 && priority > 0) {
            this.priority = priority;
        } else 
            this.priority = 1;
    }

    public ToDoItem(String task, String dueDate, int priority) {
        this.task = task;
        this.dueDate = dueDate;
        if(priority <=3 && priority > 0) {
            this.priority = priority;
        } else 
            this.priority = 1; 
    }

    public String getTask() {
        return task;
    }

    public void setTask(String task) {
        this.task = task;
    }

    public String getDueDate() {
        return dueDate;
    }

    public void setDueDate(String dueDate) {
        this.dueDate = dueDate;
    }

    public int getPriority() {
        return priority;
    }

    public void setPriority(int priority) {
        if(priority <=3 && priority > 0) {
            this.priority = priority;
        } else 
            this.priority = 1;
    }
}

Finally here is my onListItemClickListener it uses an ArrayList of ToDoItems, changes the priority and calls the update method from my data class. However the values of the row that I am trying to update remain unchanged. I used Log.d to check if the correct values were being passed and they were. For some reason the changes are not happening. Any help would be appreciated.

        todoList.setOnItemClickListener(new AdapterView.OnItemClickListener() {

    @Override
          public void onItemClick(AdapterView<?> arg0, View arg1, final int arg2,
                long arg3) {

            if(soundEnabled) {
                playSound();
            }

            // Change the priority of the item inside the arrayList todoItems
            todoItems.get(arg2).setPriority(todoItems.get(arg2).getPriority() + 1);
            String name = todoItems.get(arg2).getTask();
            int priority = todoItems.get(arg2).getPriority();
            final ToDoItem task = new ToDoItem(name, priority);

            // Get the position of the task in the database
            int id = arg2 + 1;
            data.update(id, task);


});

Answer 1

Would you print the db.update(TABLE_NAME, values, C_ID +"="+id, null) function return value?

If the return value is 0, so there is no such "id" row record in DB.