入力フィルタ(半角英数のみ入力可)

AlphaNumericInputFilter.java

/**
 * 入力フィルタ(半角英数)
 * @see <a href="http://y-anz-m.blogspot.jp/2010/10/androidfilter.html">半角英数フィルタ</a>
 */
class AlphaNumericFilter implements InputFilter {
    @Override
    public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
        if (source.toString().matches("^[a-zA-Z0-9]+$")) {
            return source;
        } else {
            return "";
        }
    }
}