APKPure Appを使用する
WiFi Password Viewerの旧いバージョンをダウンロードすることが可能
WiFi Password Viewer helps you view your connected wifi password.
'WiFi Password Viewer' helps you view your connected wifi password, which you cannot see in device default setting.
You need to ROOT your device to use 'WiFi Password Viewer', as this only works on rooted devices (needs super-user permissions) because your device stores Wi-Fi passwords when you connect to a new Wi-Fi network. You are not able to access the previous passwords and retrieve them unless you have super-user permissions. Checkout here for more information on root: http://www.androidcentral.com/root