ItemView: Item Container with Layouts

The Dali::Toolkit::ItemView class is a scrollable container that can contain many items. It provides several scrollable layouts, as illustrated in the following figure.

Figure: ItemView layouts

Grid	Spiral	Depth

You can also create your own custom layout by inheriting from the Dali::Toolkit::ItemLayout class.

Implementing ItemFactory

To create a Dali::Toolkit::ItemView instance, you must create your own ItemFactory class by deriving from the Dali::Toolkit::ItemFactory class and providing its instance to the ItemView::New() function. ItemFactory is an abstract class having 2 pure virtual member functions to create items and get the number of created items. The following basic example shows how to implement an ItemFactory class:

class MyFactory : public ItemFactory
{
  public:  
    virtual unsigned int GetNumberOfItems()
    {
      // Return the number of items
      return MY_ITEM_COUNT;
    } 
 
    virtual Actor NewItem( unsigned int itemId ) 
    { 
      // Create the actor representing the item based on the itemId
      return ImageView::New( MY_IMAGE_PATHS[itemId] );
    }
};

The overridden functions in the derived class are called by the ItemView object.

Creating an ItemView

The following basic example shows how to create a Dali::Toolkit::ItemView object:

// This sample code is for the HelloWorldExample class
// in Creating a DALi Application
class HelloWorldExample : public ConnectionTracker
{
  // Store a factory as a member variable
  MyFactory mFactory; 
};

void HelloWorldExample::Create( Application& application )
{
  // Create an ItemView with the factory
  ItemView itemView = ItemView::New( mFactory ); 
  itemView.SetParentOrigin( ParentOrigin::CENTER );

  // Create a layout
  ItemLayoutPtr spiralLayout = DefaultItemLayout::New( DefaultItemLayout::SPIRAL );

  // Add the layout to the itemView
  itemView.AddLayout( *spiralLayout );
  // More layouts can be created and added to the itemView

  // Activate the layout
  itemView.ActivateLayout( 0, Vector3( Stage::GetCurrent().GetSize() ), 0 );

  // Add the itemView to the stage
  Stage::GetCurrent().Add( itemView );
}