Question

In my apps I currently only support the portrait orientation for some activities, because I assume that most phone users will be using portrait orientation (and holding the device with one hand) most of the time.

On the new Honeycomb tablets, however, it seems likely that users will be using the landscape orientation much more often, so I’d like to support both orientations for more of my activities.

I’d rather not have to go back and add landscape layouts for the smaller screen sizes (all the way down to QVGA), though, so I’m wondering if there’s a way of supporting landscape only for the xlarge screen type but not for the others.

Answer 1

You can combine the orientation and size attributes on the resource objects like:

res/layout/             -- default
res/layout-port/        -- portrait for any screen size
res/layout-xlarge/      -- any orientation on xlarge screens
res/layout-xlarge-land/ -- landscape on xlarge screens

Use the layout-port directory for your portrait-only layouts for smaller screen sizes, and then add your xlarge layouts to the layout-xlarge directory if you want to use the same layout file for portrait and landscape on xlarge, or to layout-xlarge-land and layout-xlarge-port if you want different layout files depending on the orientation.

Then, when you rotate to landscape on a smaller-screened device the OS will try to load a landscape layout but fail because there isn’t one that matches and throw a Resources.NotFoundException. You can catch that exception, though, and force the activity to portrait mode in those cases using Activity.setRequestedOrientation():

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    try {
        setContentView(R.layout.titlescreen);
    } catch (Resources.NotFoundException e) {
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        return;
    }
    [...]
}

That will then cause the activity to be recreated in portrait mode and it won’t try to change again because using setRequestedOrientation() overrides the orientation sensor.