Android spinner - Cannot make a static reference to the non-static method help

I have followed a tutorial to populate data from an sqlite database in to a spinner (dropdown) in Android. However, I am getting the error:

Cannot make a static reference to the non开发者_运维知识库-static method fetchAllCategories() from the type DatabaseAdapter

My code is as follows:

In EditTask:

private void fillData() {
        Cursor categoriesCursor;
        Spinner categoriesSpinner = (Spinner) findViewById(R.id.spinDept);
        categoriesCursor = DatabaseAdapter.fetchAllCategories();

        startManagingCursor(categoriesCursor);

        String[] from = new String[] { DatabaseAdapter.CAT_NAME };

        int[] to = new int[] { R.id.tvDBViewRow }; //this part hasnt been implemented in to the layout yet

        SimpleCursorAdapter categoriesAdapter = new SimpleCursorAdapter(this,
                R.layout.db_view_row, categoriesCursor, from, to);

        categoriesSpinner.setAdapter(categoriesAdapter);
    }

And in my DatabaseAdapter class I have the following:

public Cursor fetchAllCategories() {
    if (mDb == null) {
        this.open();
    }
    String tableName = "CAT_TABLE";
    return mDb.query(tableName, new String[] { CAT_ID, CAT_NAME }, null,
            null, null, null, null);
}

The offending line of code is:

categoriesCursor = DatabaseAdapter.fetchAllCategories();

I'm pretty new to Java/Android so it may be something simple/obvious but any help is much appreciated!

---

You have to first instantiate a DatabaseAdapter object. eg:

DatabaseAdapter myDbAdapter = new DatabaseAdapter();
categoriesCursor = myDbAdapter.fetchAllCategories();

---

to be able to make your code work, you need to declare the method fetchAllCategoires() as static as follows:

public static Cursor fetchAllCategories() 

Because you have not instantiated a DatabaseAdapter object, you cannot just call one of it's methods by a class name reference unless the keyword static appears in the method declaration.