Q:

Android How to launch Google + Photos activity?

The Google Plus app contains two separate apps inside the one app. One app is the Google Photos App itself while the other is a Photos app. Launching the Google Plus app is simple since all you need is the Intent action name of the app, but how would you launch the photos app that is inside the G+ app. 
Something like this:
startActivity(new Intent("com.google.android.apps.plus.photos"));

But of coarse this just force closes due to the intent not being found. 

A:

Try following
    Intent intent = new Intent("android.intent.action.MAIN");  
    intent.setComponent(ComponentName.unflattenFromString("com.google.android.apps.plus.photos"));
    intent.addCategory("android.intent.category.LAUNCHER");
    intent.setPackage("com.google.android.apps.plus");
    startActivity(intent);

or:
Intent i;
PackageManager manager = getPackageManager();
try {
    i = manager.getLaunchIntentForPackage("com.google.android.apps.plus.photos");
    if (i == null)
        throw new PackageManager.NameNotFoundException();
    i.addCategory(Intent.CATEGORY_LAUNCHER);
    startActivity(i);
} catch (PackageManager.NameNotFoundException e) {

}

