Multiband light curves of two RR-Lyrae variables in SegueII and Ursa-MajorII ultrafaint dwarf galaxies were collected from near simultaneous observations using the Lulin One-meter Telescope in Vgri bands. Together with Gaia G-band light curves, we determined photometric metallicities using empirical relations involving pulsation period and Fourier parameter as dependent parameters. We demonstrated that the RR-Lyrae photometric metallicity can be determined accurately when these empirical relations were employed at multiple wavelengths, which can potentially improve the distance determination based on RR-Lyrae stars. The photometric metallicities based on our approach were found to be -2.27{+/-}0.13dex and -1.87{+/-}0.16dex for the RR-Lyrae in SegueII and Ursa-MajorII UFD, respectively, with corresponding distance moduli of 17.69{+/-}0.15 mag and 17.58{+/-}0.15 mag, in agreement with previous literature determinations. This approach of photometric metallicity of RR Lyrae based on multiband optical light curves will be particularly relevant for distance measurements in the era of the Vera C Rubin's Legacy Survey of Space and Time.