Field Alignment Using RIM's Alignment Styles

It is more efficient to align fields manually by overriding sublayout() since it does not require extra wrapper managers. See Centering a Field in a HorizontalFieldManager for an example.

Field alignment is not as straight forward as it could be on the Blackberry. The
Field class provides the following style bits for alignment:

• Horizontal alignment styles
  • FIELD_LEFT
  • FIELD_HCENTER
  • FIELD_RIGHT
• Vertical alignment styles
  • FIELD_TOP
  • FIELD_VCENTER
  • FIELD_BOTTOM

The horizontal alignment styles are only recognized when a Field is added to a VerticalFieldManager, and the vertical alignment styles only apply when a Field is added to a HorizontalFieldManager. Below is a simple example that should illustrate the basic idea.

Creating a HorizontalFieldManager containing fields aligned to either side

We'll assume you've created the following objects:

ButtonField leftField = new ButtonField( "Left", null, Field.FIELD_LEFT );
ButtonField rightField = new ButtonField( "Right", null, Field.FIELD_RIGHT );

HorizontalFieldManager horizontalFieldManager = new HorizontalFieldManager();

Fields added to a HorizontalFieldManager are ALWAYS aligned to the left. This is the correct behavior for the leftField, so we can simply add it directly to the HorizontalFieldManager:

horizontalFieldManager.add( leftField );

The rightField on the other-hand MUST be added to a VerticalFieldManager in order to be aligned to the right. We can accomplish this with the following code:

VerticalFieldManager rightFieldManager = new VerticalFieldManager(Field.USE_ALL_WIDTH);
rightFieldManager.add( rightField );
horizontalFieldManager.add( rightFieldManager );

We must create a VerticalFieldManager that consumes the remaining width of the HorizontalFieldManager. When the rightField is added to this VerticalFieldManager it will be aligned to the right side of the manager, and subsequently to the right side of the screen.