Determining if an Activity exists on the current device?

Question

Is there a way to check and see if an Activity exists on your device? If I have a youtube video link I want to specify it open in the YouTube PlayerActivity. However, I don\

Answer 1

I ended up doing:

        Intent intent = new Intent();
        intent.setClassName( "com.google.android.gsf", "com.google.android.gsf.login.AccountIntroActivity" );

        if(getContext().getPackageManager().resolveActivity(intent, PackageManager.MATCH_DEFAULT_ONLY) != null) {
            getContext().startActivity( intent );
        } else {
            getContext().startActivity(new Intent(Settings.ACTION_ADD_ACCOUNT));
        }

This ensures that the google-specific Add Account intent exists, and if not, falls back on the general more general ACTION_ADD_ACCOUNTS.