APL Keys provides a full set of APL characters in a familiar layout. In addition to the full qwerty keyboard with overloaded keys there are two dedicated APL views, a phone pad and a symbol view.

Please note that although all APL characters are available in the IME, it is up to the target application to ensure that the glyphs are rendered properly (by using a font that includes the APL glyphs). This means that you may type APL characters and not see the expected text. They are there however, and if you post emails or messages and the receiver has an APL font they will see the text rendered properly.

For a simple notepad that supports APL characters you can use the included app "APL Pad"