SQLite Data Binding

Slides By: Amit Kotlovski

The Problem

• We have a Database holding all our data
• We can get a Cursor with the data we want to display
• We want to display the data in a ListView

A Possible Solution

• Create an ArrayList
• Iterate over the Cursor and add its contents to the ArrayList
• Use an ArrayAdapter to connect to the ListView

Issues with the Solution

Complication

• We need to create a temporary collection each time
• We need to iterate all the items in the Cursor

Issues with the Solution

Efficiency / Performance

• For a very big Cursor will take a lot of time iterate it
• Even if the user only looks at the first few items

Issues with the Solution

Limiting

• Hard to display a complex View for each item

A Better Solution

An Adapter for Cursors

Enter SimpleCursorAdapter

An Adapter that wraps a Cursor

SimpleCursorAdapter

Connects columns in the Cursor data to TextViews and ImageViews in a Layout

SimpleCursorAdapter

Syntax

// FROM
String[] cols = new String[] { NAME_COL_NAME, DESCRIPTION_COL_NAME };

// TO
int[] ids = new int[] { R.id.name_txt, R.id.desc_txt};

SimpleCursorAdapter adapter =
        new SimpleCursorAdapter(this,               // Context
                                R.layout.item,      // Item layout
                                cursor,             // Results cursor
                                cols,               // Columns
                                ids,                // Views
                                0);                 // Special flags

But What If We Need More?

• Column data that requires processing before display
• Data that does not fit neither a TextView nor ImageView

Meet the ViewBinder

• Allow basic columns → id mapping
• Enable manual override for some mappings

ViewBinder

• Allows customizing the translation of Cursor data by handling specific columns' data presentations

Answers and Questions

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