public class MiuiUtils {

  private MiuiUtils() {
    throw new UnsupportedOperationException("u can't instantiate me...");
  }

  private static final String KEY_MIUI_VERSION_CODE = "ro.miui.ui.version.code";
  private static final String KEY_MIUI_VERSION_NAME = "ro.miui.ui.version.name";
  private static final String KEY_MIUI_INTERNAL_STORAGE = "ro.miui.internal.storage";
  public static final int REQUEST_CODE_SERVICE_SMS = 100;


  /**
   * @return whether or not is MIUI
   * @link http://dev.xiaomi.com/doc/p=254/index.html
   */
  public static boolean isMIUI() {
    String device = Build.MANUFACTURER;
    LogUtils.v("Build.MANUFACTURER = " + device);
    if (device.equals("Xiaomi")) {
      Properties prop = new Properties();
      try {
        prop.load(new FileInputStream(new File(Environment
            .getRootDirectory(), "build.prop")));
      } catch (IOException e) {
        e.printStackTrace();
        return false;
      }
      return prop.getProperty(KEY_MIUI_VERSION_CODE, null) != null
          || prop.getProperty(KEY_MIUI_VERSION_NAME, null) != null
          || prop.getProperty(KEY_MIUI_INTERNAL_STORAGE, null) != null;
    } else {
      return false;
    }
  }


  public static void goPermissionSettings(Activity context) {
    Intent intent;
    try {//MIUI8/9
      intent = new Intent("miui.intent.action.APP_PERM_EDITOR");
      intent.setClassName("com.miui.securitycenter",
          "com.miui.permcenter.permissions.PermissionsEditorActivity");
      intent.putExtra("extra_pkgname", context.getPackageName());
      context.startActivityForResult(intent, REQUEST_CODE_SERVICE_SMS);
    } catch (ActivityNotFoundException e) {
      try {//MIUI5/6
        intent = new Intent("miui.intent.action.APP_PERM_EDITOR");
        intent.setClassName("com.miui.securitycenter",
            "com.miui.permcenter.permissions.AppPermissionsEditorActivity");
        intent.putExtra("extra_pkgname", context.getPackageName());
        context.startActivityForResult(intent, REQUEST_CODE_SERVICE_SMS);
      } catch (ActivityNotFoundException e1) {
        //應用信息界面
        intent = new Intent(
            Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
        Uri uri = Uri.fromParts("package", context.getPackageName(),
            null);
        intent.setData(uri);
        context.startActivityForResult(intent, REQUEST_CODE_SERVICE_SMS);;
      }
    }
  }
}

adb shell dumpsys activity | findstr "mFocusedActivity"