@Override
        public List<PermissionGroup> loadInBackground() {
            ArraySet<String> launcherPkgs = Utils.getLauncherPackages(getContext());
            PermissionApps.PmCache pmCache = new PermissionApps.PmCache(
                    getContext().getPackageManager());

            List<PermissionGroup> groups = new ArrayList<>();
            Set<String> seenPermissions = new ArraySet<>();

            PackageManager packageManager = getContext().getPackageManager();
            List<PermissionGroupInfo> groupInfos = packageManager.getAllPermissionGroups(0);

            for (PermissionGroupInfo groupInfo : groupInfos) {
                // Mare sure we respond to cancellation.
                if (isLoadInBackgroundCanceled()) {
                    return Collections.emptyList();
                }

                // 得到权限组里的所有权限
                // Get the permissions in this group.
                final List<PermissionInfo> groupPermissions;
                try {
                    groupPermissions = packageManager.queryPermissionsByGroup(groupInfo.name, 0);
                } catch (PackageManager.NameNotFoundException e) {
                    continue;
                }

                boolean hasRuntimePermissions = false;

                // 查看某个权限组是否含有运行时权限
                // Cache seen permissions and see if group has runtime permissions.
                for (PermissionInfo groupPermission : groupPermissions) {
                    seenPermissions.add(groupPermission.name);
                    if ((groupPermission.protectionLevel & PermissionInfo.PROTECTION_MASK_BASE)
                            == PermissionInfo.PROTECTION_DANGEROUS
                            && (groupPermission.flags & PermissionInfo.FLAG_INSTALLED) != 0
                            && (groupPermission.flags & PermissionInfo.FLAG_REMOVED) == 0) {
                        hasRuntimePermissions = true;
                    }
                }

                // 权限组里没有运行时权限，我们不感兴趣，继续循环查询
                // No runtime permissions - not interesting for us.
                if (!hasRuntimePermissions) {
                    continue;
                }

                // 如果权限组里含有运行时权限，则继续往下执行

                // 获取权限组的label
                CharSequence label = loadItemInfoLabel(groupInfo);
                Drawable icon = loadItemInfoIcon(groupInfo);

                // 根据权限组 新建 PermissionApps 对象
                PermissionApps permApps = new PermissionApps(getContext(), groupInfo.name, null,
                        pmCache);
                permApps.refreshSync();

                // 创建 PermissionGroup 对象
                // Create the group and add to the list.
                PermissionGroup group = new PermissionGroup(groupInfo.name,
                        groupInfo.packageName, label, icon, permApps.getTotalCount(launcherPkgs),
                        permApps.getGrantedCount(launcherPkgs));
                groups.add(group);
            }


            // 获取所有的安装包权限
            // Make sure we add groups for lone runtime permissions.
            List<PackageInfo> installedPackages = getContext().getPackageManager()
                    .getInstalledPackages(PackageManager.GET_PERMISSIONS);


            // We will filter out permissions that no package requests.
            Set<String> requestedPermissions = new ArraySet<>();
            for (PackageInfo installedPackage : installedPackages) {
                if (installedPackage.requestedPermissions == null) {
                    continue;
                }
                // 将安装包请求的权限加入到 列表中
                for (String requestedPermission : installedPackage.requestedPermissions) {
                    requestedPermissions.add(requestedPermission);
                }
            }

            for (PackageInfo installedPackage : installedPackages) {
                if (installedPackage.permissions == null) {
                    continue;
                }

                // 自定义的权限
                for (PermissionInfo permissionInfo : installedPackage.permissions) {
                    // If we have handled this permission, no more work to do.
                    if (!seenPermissions.add(permissionInfo.name)) {
                        continue;
                    }

                    // 关心的是 运行时权限
                    // We care only about installed runtime permissions.
                    if ((permissionInfo.protectionLevel & PermissionInfo.PROTECTION_MASK_BASE)
                            != PermissionInfo.PROTECTION_DANGEROUS
                            || (permissionInfo.flags & PermissionInfo.FLAG_INSTALLED) == 0) {
                        continue;
                    }

                    // 没有app使用那个自定义的权限
                    // If no app uses this permission,
                    if (!requestedPermissions.contains(permissionInfo.name)) {
                        continue;
                    }

                    CharSequence label = loadItemInfoLabel(permissionInfo);
                    Drawable icon = loadItemInfoIcon(permissionInfo);

                    PermissionApps permApps = new PermissionApps(getContext(), permissionInfo.name,
                            null, pmCache);
                    permApps.refreshSync();

                    // Create the group and add to the list.
                    PermissionGroup group = new PermissionGroup(permissionInfo.name,
                            permissionInfo.packageName, label, icon,
                            permApps.getTotalCount(launcherPkgs),
                            permApps.getGrantedCount(launcherPkgs));
                    groups.add(group);
                }
            }

            Collections.sort(groups);
            return groups;
        }

  /**
     * Refresh the state and do not return until it finishes. Should not be called while an {@link
     * #refresh async referesh} is in progress.
     */
    public void refreshSync() {
        mSkipUi = true;
        createMap(loadPermissionApps());
    }

/**
 * For each permission there are four events. The events are in the order of
 * #ALL_DANGEROUS_PERMISSIONS. The four events per permission are (in that order): "requested",
 * "granted", "denied", and "revoked".
 */
public class EventLogger {
    private static final String LOG_TAG = EventLogger.class.getSimpleName();

    /** All dangerous permission names in the same order as the events in MetricsEvent */
    private static final List<String> ALL_DANGEROUS_PERMISSIONS = Arrays.asList(
            Manifest.permission.READ_CALENDAR,
            Manifest.permission.WRITE_CALENDAR,
            Manifest.permission.CAMERA,
            Manifest.permission.READ_CONTACTS,
            Manifest.permission.WRITE_CONTACTS,
            Manifest.permission.GET_ACCOUNTS,
            Manifest.permission.ACCESS_FINE_LOCATION,
            Manifest.permission.ACCESS_COARSE_LOCATION,
            Manifest.permission.RECORD_AUDIO,
            Manifest.permission.READ_PHONE_STATE,
            Manifest.permission.CALL_PHONE,
            Manifest.permission.READ_CALL_LOG,
            Manifest.permission.WRITE_CALL_LOG,
            Manifest.permission.ADD_VOICEMAIL,
            Manifest.permission.USE_SIP,
            Manifest.permission.PROCESS_OUTGOING_CALLS,
            Manifest.permission.READ_CELL_BROADCASTS,
            Manifest.permission.BODY_SENSORS,
            Manifest.permission.SEND_SMS,
            Manifest.permission.RECEIVE_SMS,
            Manifest.permission.READ_SMS,
            Manifest.permission.RECEIVE_WAP_PUSH,
            Manifest.permission.RECEIVE_MMS,
            Manifest.permission.READ_EXTERNAL_STORAGE,
            Manifest.permission.WRITE_EXTERNAL_STORAGE,
            Manifest.permission.READ_PHONE_NUMBERS,
            Manifest.permission.ANSWER_PHONE_CALLS,
            Manifest.permission.ACCEPT_HANDOVER);

    private static final List<String> ALL_APPOP_PERMISSIONS = Arrays.asList(
            Manifest.permission.ACCESS_NOTIFICATIONS,
            Manifest.permission.SYSTEM_ALERT_WINDOW,
            Manifest.permission.WRITE_SETTINGS,
            Manifest.permission.REQUEST_INSTALL_PACKAGES);

......

}

    public static final String OS_PKG = "android";

    public static final String[] MODERN_PERMISSION_GROUPS = {
            Manifest.permission_group.CALENDAR,
            Manifest.permission_group.CAMERA,
            Manifest.permission_group.CONTACTS,
            Manifest.permission_group.LOCATION,
            Manifest.permission_group.SENSORS,
            Manifest.permission_group.SMS,
            Manifest.permission_group.PHONE,
            Manifest.permission_group.MICROPHONE,
            Manifest.permission_group.STORAGE
    };

    private static final Intent LAUNCHER_INTENT = new Intent(Intent.ACTION_MAIN, null)
                            .addCategory(Intent.CATEGORY_LAUNCHER);