https://tetzzang.com/android-%ed%95%9c%ea%b8%80-%ec%82%ac%ec%9a%a9%ec%9e%90-%eb%aa%85%ec%9c%bc%eb%a1%9c-%ec%9d%b4%ed%81%b4%eb%a6%bd%ec%8a%a4%ec%97%90%ec%84%9c-%eb%a7%8c%eb%93%a0-avd-%ec%97%90%eb%9f%ac-%ec%b2%98%eb%a6%ac/