/**

     * Class used to reduce the number of calls to the package manager.

     * This caches app information so it should only be used across parallel PermissionApps

     * instances, and should not be retained across UI refresh.

     */

    public static class PmCache {

        private final SparseArray<List<PackageInfo>> mPackageInfoCache = new SparseArray<>();

        private final PackageManager mPm;

        public PmCache(PackageManager pm) {

            mPm = pm;

        }

        public synchronized List<PackageInfo> getPackages(int userId) {

            List<PackageInfo> ret = mPackageInfoCache.get(userId);

            if (ret == null) {

                ret = mPm.getInstalledPackagesAsUser(PackageManager.GET_PERMISSIONS, userId);

                mPackageInfoCache.put(userId, ret);

            }

            return ret;

        }

    }

private final PmCache mCache;

List<PackageInfo> apps = mCache != null ? mCache.getPackages(user.getIdentifier())

                    : mPm.getInstalledPackagesAsUser(PackageManager.GET_PERMISSIONS,

                            user.getIdentifier());