Android EditText 最简单的限制输入字母和数字

private static final String DIGISTS = "0123456789" +
         "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
private DigitsKeyListener digitsKeyListener;//输入框过滤器
...

digitsKeyListener  =  new DigitsKeyListener() {
    @Override
    public int getInputType() {
        return InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_NORMAL;
    }
    @Override
    protected char[] getAcceptedChars() {
        return DIGISTS.toCharArray();
    }
};
mEditPsw.setKeyListener(digitsKeyListener);