How can restrict my EditText input to some special character like backslash(/),tild(~) etc by soft keyboard in android programmatically

Question

I am developing an application for keyboard, but i am geting an issue. I want to restrict/block some special character from soft keyboard in EditText in android programmatic

Answer 1

Unfortunately the accepted solution doesn't work in all the cases. The proper solution would be to use the following InputFilter:

private InputFilter filter = new InputFilter() {
    // An example pattern that restricts the input only to the lowercase letters
    private static final Pattern restrictedChars = Pattern.compile("[a-z]*")

    @Override
    public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
        final CharSequence replacementText = source.subSequence(start, end);
        final CharSequence replacedText = dest.subSequence(dstart, dend);

        if (source == null || restrictedChars.matcher(replacementText).matches()) {
            return null; // Accept the original replacement
        }

        return replacedText; // Keep the original text
    }
};

This solution differs from the accepted one in that it solves the following problems:

• only a subsequence of the source is the replacement, not the full source
• source doesn't necessarily include only the newly typed text, sometimes it is the full text typed so-far