public class MyApplication extends Application{

    @Override
    public void onCreate() {
        super.onCreate();
        TwitterAuthConfig authConfig = new TwitterAuthConfig(TWITTER_KEY, TWITTER_SECRET);
        Fabric.with(this, new Twitter(authConfig));
        FacebookSdk.sdkInitialize(getApplicationContext());
        AppEventsLogger.activateApp(this);
        try {
            @SuppressLint("PackageManagerGetSignatures") PackageInfo info = getPackageManager().getPackageInfo(
                    "com.tettares.whatdoieat",
                    PackageManager.GET_SIGNATURES);
            for (Signature signature : info.signatures) {
                MessageDigest md = MessageDigest.getInstance("SHA");
                md.update(signature.toByteArray());
                Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT));
            }
        } catch (PackageManager.NameNotFoundException | NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
    }
}