Question: There is already a good SO question for displaying a Google+ Page in the Google+ Android app:

[Open Google Plus Page Via Intent In Android](https://stackoverflow.com/questions/11867989/open-google-plus-page-via-intent-in-android)

But what about the Intent to launch the Google+ app at a specific Google+ Community?

EDIT - to the silent down-voters, please explain why you down-voted.

Answer: 
I achieved this by using: 

```
String communityPage = "communities/123456789";
    try {
        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setClassName("com.google.android.apps.plus",
                "com.google.android.apps.plus.phone.UrlGatewayActivity");
        intent.putExtra("customAppUri", communityPage);
        startActivity(intent);
        } catch(ActivityNotFoundException e) {
            // fallback if G+ app is not installed
            startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("https://plus.google.com/"+communityPage)));
        }

```

Where 123456789 is the id of the community copied from the address bar.
Just in case anyone else needs to do this I had to do this in my app and used the below code

```
startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("https://plus.google.com/communities/1234356789")));

```

Where 1234356789 is the community id from the address bar.

This then prompts whether you want to open with Google+ or browser.