Question

I can’t seem to figure out this SimpleCursorAdapter, every time I fix one error, another one pops up and if I follow the steps to fix that one, the first one comes up again. I feel like I’m going in circles here, so here’s the chunk of code I’m trying to debug, note, the first part is just creating the DB, but I figured anything could be helpful in figuring it out.

        SQLiteDatabase rpgDB = null;
        String classFields = " (classID, className, classHP)";

        try {
            rpgDB = this.openOrCreateDatabase("RpgDB", MODE_PRIVATE, null);
            rpgDB.execSQL("DROP TABLE IF EXISTS " + classTable);

            rpgDB.execSQL("CREATE TABLE IF NOT EXISTS " + classTable + " (classID INT(3), className TEXT, classHP INT(4));");
            rpgDB.execSQL("INSERT INTO " + classTable + classFields + " VALUES (1, 'Warrior', 10);");
            rpgDB.execSQL("INSERT INTO " + classTable + classFields + " VALUES (2, 'Rogue', 7);");
            rpgDB.execSQL("INSERT INTO " + classTable + classFields + " VALUES (3, 'Mage', 5);");


            String query = "SELECT className AS _id FROM " + classTable;
            Cursor cursor = rpgDB.rawQuery(query, null);
            rpgDB.close();

            int[] to = new int[] { R.id.classDropDown };
            String[] spinnerFields = new String[] { "_id" };
            /**
             * Test code to check value of cursor
             */ 
            int count = cursor.getCount();
            cursor.moveToFirst();
            while (cursor.isAfterLast() == false) 
            {
                String test  = cursor.getString(0);
                cursor.moveToNext();
            }

            SimpleCursorAdapter cursorAdapter = new SimpleCursorAdapter(this, R.layout.main, cursor, spinnerFields, to);
            int cursorcount = cursorAdapter.getCount();
            // cursorAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            Spinner classDropDown = (Spinner) this.findViewById(R.id.classDropDown);
            classDropDown.setAdapter(cursorAdapter);
        } catch (Exception ex) {
            System.out.println("Exception: " + ex);
        }

Populating a Spinner from a SimpleCursorAdapter seems to be ridiculously troublesome.

EDIT: The error with this code is

Invalid statement in fill window

If I comment out the rpgDB.close() line

Spinner is not a view that can be bounds by this SimpleCursorAdapter

If I change the select statement and spinnerfields to (with the DB commented out):

String query = "SELECT className FROM " + classTable;
String[] spinnerFields = new String[] { "className" };

I get:

column '_id' does not exist

EDIT XML: Here is the main.xml (also id main) XML

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/main"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:background="@color/white" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:textSize="11pt"
        android:text="@string/hello"
        android:textColor="@color/baseTextColor" />

    <Spinner
        android:id="@+id/classDropDown"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />


</LinearLayout>

EXPLANATION: So if anyone comes upon this in the future, thanks to Luksprog, I understand this a bit better (and he showed me the fixes):

The android.R.id and android.R.layout “ids/layouts” are default xml layouts for Android components such as a TextField and Spinner “list” layouts. The Spinner object is basically NOT complete on its own. You need another XML portion to define how the list itself looks and another one for the lines (the text1 is a default android TextField).

So in short, assign your “to” field to a TextField or use one of the default Android ones such as android.id.text1, but in order to use that I believe you also have to use the layout that CONTAINS the default android field, andoid.R.layout (in my case, simple_spinner_item). Lastly, set the dropdownresource to your own xml or an android default (mine was android.R.layout.simple_spinner_dropdown_item).

Answer 1

Check this:

String query = "SELECT _id, className FROM " + classTable;
Cursor cursor = rpgDB.rawQuery(query, null);
int[] to = new int[] { android.R.id.text1 };
String[] spinnerFields = new String[] { "className"};
SimpleCursorAdapter cursorAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_spinner, cursor, spinnerFields, to);
cursorAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
Spinner classDropDown = (Spinner) this.findViewById(R.id.classDropDown);
classDropDown.setAdapter(cursorAdapter);

Invalid statement in fill window

You can’t close the database connection if you want to pull data from that Cursor.

Spinner is not a view that can be bounds by this SimpleCursorAdapter

The to int array represents the ids of the Views from the row layout file that you pass to the SimpleCursorAdapter to bind data from the from array (R.layout.main, I hope that you do have a layout file and just pass the activity’s layout). The id R.id.classDropDown that you used there represents a Spinner view and a SimpleCursorAdapter doesn’t know how to bind data to that(it can bind data to a TextView or ImageView). If you want a Spinner on each row(do you really want this? or do you want the default spinner row layout?) then use a custom adapter or a SimpleCursorAdapter.ViewBinder.

column ‘_id’ does not exist

Because you don’t have a column with this name in the table classTable. This column should be declared like:

INTEGER PRIMARY KEY AUTOINCREMENT

Maybe you can check this simple tutorial for Spinners.