CODEWITHSUNDEEP
androidsqlitelistview
Socaprice
Socaprice

Reputation: 55

Loading a ListView Adapter in Android

I am trying to load an Adapter from a SQLite database and I cannot seem to wrap my head around how this works. I am extremely new to Android and Java programming so forgive if I stumble around some of the obvious.

I understand that to have a "proper" database setup I must have the 3 java files, the Main, DatabaseHandler and the class for whatever my table is, so getting there. I have most of working in some form but I cannot seem to get my ListView to load with the rows in my table.

I only have one table with two columns, ID and Item. The code in the DatabaseHandler to get all the items is shown below:

public List<Item> getAllItems()
{
    List<Item> itemList = new ArrayList<Item>();
    String selectQuery = "SELECT * FROM " + TABLE_ITEMS;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    if (cursor.moveToFirst())
    {
        do {
            Item item = new Item();
            item.setID(Integer.parseInt(cursor.getString(0)));
            item.setItem(cursor.getString(1));
            itemList.add(item);
        } while (cursor.moveToNext());
    }
    return itemList;
}

How do put that into a ListView Adapter in the main activity? This is what I tried below and it did not work I was getting pointer positions instead:

    List itemArray = db.getAllItems();
    //Define a new Adapter
    ArrayAdapter<List> adapter = new ArrayAdapter<List>(this,
            android.R.layout.simple_list_item_1, android.R.id.text1, itemArray);

    //Bind the adapter to the listView
    itemView.setAdapter(adapter);

How do I load the items in?

Thanks for any help given.

Socaprice

Upvotes: 0

Views: 905

Answers (3)

Simas
Simas

Reputation: 44118

You can use a SimpleCursorAdapter here. You won't have to parse anything yourself and you won't need a custom adapter.

First adjust your DB method to return a Cursor:

public Cursor getData() {
    String selectQuery = "SELECT * FROM " + TABLE_ITEMS;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    return cursor;
}

Next create and set the SimpleCursorAdapter:

Cursor cursor = db.getData();
String[] from = new String[] { "StringColumn" };
int[] to = new int[] { android.R.id.text1 };

SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,
        android.R.layout.simple_list_item_1, cursor, from, to, 0);

listView.setAdapter(adapter);

Note: Change "StringColumn" to the DB column name that will be used.

Edit: You can fetch the column names afterwards like this:

String itemColumn = cursor.getColumnName(1);

And then use it for the SimpleCursorAdapter:

String[] from = new String[] { itemColumn };

Upvotes: 2

Hadi Satrio
Hadi Satrio

Reputation: 4292

Unless you're working with a simple String array, you would have to implement your own adaptation of ArrayAdapter along with its getView() method in order to actually use it in an AdapterView.

This is a great place to start.

But to give you a rough idea on this (and as I don't justify answering an SO question by only giving links) your ArrayAdapter would work like this:

  • Make an XML layout for your ListView item. Tis coul be a simple TextView or complex, composite View.
  • Pass your List<Item> to the adapter and save it as a global variable (or field).
  • Override ArrayAdapter's getView() to bind the TextViews Buttons you might have in your XML layout defined above with the actual data from your List<Item>. Android automatically called this method, passing the actual position, so that you could call the relevant item in your list.

Upvotes: 0

loose11
loose11

Reputation: 627

You should write your own ArrayAdapter. Because the normal ArrayAdapter dont know your item, so he can't do anything with it.

See Custom Array Adapter example / tutorial

Upvotes: 0

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