Portrait and landscape orientation
In most cases, you should lay out your app in portrait view. Users tend to hold their BlackBerry smartphone in one hand, and therefore, typically use it in portrait view. Plus, smartphones with a physical keyboard use portrait view exclusively.
Sometimes, landscape view can offer benefits and provide a better experience for users of all-touch BlackBerry smartphones. For example, movies and games. Movies are made to be viewed in wide screen, and games often require two-handed interaction, which suits a landscape orientation well.
In some cases, you might lay out your application in both portrait and landscape orientation. This approach lets you provide a different focus in each orientation to enrich the user experience. For example, you could show a basic calculator in portrait orientation and a more advanced version in landscape orientation.
If you create custom UI components, make sure the components appear correctly in both orientations. If you use BlackBerry UI components, they're designed to transition seamlessly if users switch between views.
Maintain consistency. Don't force your users to switch between orientations manually as they use your app. If a screen supports landscape orientation, any subsequent screen should also be available in that orientation.
Don't create views in landscape orientation for smartphones with a 1:1 aspect ratio. The BlackBerry Application Platform does not support landscape orientation on smartphones with a 1:1 aspect ratio.