For some reason Android defaults to some kind of Chinese-Japanese-Korean compatibility font when the OS language is English, and it looks terrible. As Ryuudou said, changing the OS language to Japanese will use a standard Japanese font. It's more of an inconvenient workaround than a solution though, and Google is to blame for not providing something better.
As for AnkiDroid, you can use custom fonts by copying them into the media folder (the filename should be prefixed with an underscore), and then specifying them with CSS in the card styles (follow the link in Zarxrax's post). I have a bad feeling that the entire font is loaded into memory each time a card is loaded card though, since there's a significant delay with the stroke order font on each of my cards, despite having a device with 2-3GB of RAM.
As for AnkiDroid, you can use custom fonts by copying them into the media folder (the filename should be prefixed with an underscore), and then specifying them with CSS in the card styles (follow the link in Zarxrax's post). I have a bad feeling that the entire font is loaded into memory each time a card is loaded card though, since there's a significant delay with the stroke order font on each of my cards, despite having a device with 2-3GB of RAM.