The question of viruses on Android-powered devices goes way back to 2010 when Kaspersky Labs identified the “first virus targeted at the Android operating system”. The particular virus, Trojan-SMS.AndroidOS.FakePlaye r.a, was a Trojan distributed through a text message asking users to install a 13KB “harmless” media player app. It was anything but harmless.
Fortunately, Android is set up such that applications installed from third-party sources are blocked by default. To actually infect your phone you would have had to consciously disable that feature, and accepted the warning which Android presents when doing so. In other words, you were given the choice whether or not you wanted to assume the risk.