Text input

RegexInputFilter.java

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import android.text.InputFilter;
import android.text.Spanned;


public class RegexInputFilter implements InputFilter {
	private Pattern mPattern;

	public RegexInputFilter(String pattern) {
		mPattern = Pattern.compile(pattern);
	}

	@Override
	public CharSequence filter(CharSequence source, int sourceStart, int sourceEnd, Spanned destination, int destinationStart, int destinationEnd) {
		String textToCheck = destination.subSequence(0, destinationStart).toString()
		                     + source.subSequence(sourceStart, sourceEnd)
		                     + destination.subSequence(destinationEnd, destination.length()).toString();

		Matcher matcher = mPattern.matcher(textToCheck);
		if (!matcher.matches() && !matcher.hitEnd()) {
				return "";
		}
		return null;
	}
}

UserIdEditText.java

import android.content.Context;
import android.support.v7.widget.AppCompatEditText;
import android.text.Editable;
import android.text.InputFilter;
import android.text.InputType;
import android.text.method.DigitsKeyListener;
import android.util.AttributeSet;

public class UserIdEditText extends AppCompatEditText {
	public static final int MINIMAL_USER_ID_LENGTH = 10;

	public UserIdEditText(Context context) {
		super(context);
	}

	public UserIdEditText(Context context, AttributeSet attrs) {
		super(context, attrs);
	}

	public UserIdEditText(Context context, AttributeSet attrs, int defStyleAttr) {
		super(context, attrs, defStyleAttr);
	}

	@Override
	protected void onFinishInflate() {
		super.onFinishInflate();

		setInputType(InputType.TYPE_CLASS_NUMBER);
		setKeyListener(DigitsKeyListener.getInstance("0123456789-"));

		setFilters(new InputFilter[]{
				new RegexInputFilter("\\d{3}-\\d{6,7}")
		});

		addTextChangedListener(new TextWatcherAdapter() {
			int mPreviousLength;

			@Override
			public void beforeTextChanged(CharSequence s, int start, int count, int after) {
				mPreviousLength = s.length();
			}

			@Override
			public void afterTextChanged(Editable text) {
				if (mPreviousLength < 3 && text.length() == 3) {
					text.append('-');
				} else if (mPreviousLength > 3 && text.length() == 3) {
					text.delete(2, 3);
				}
			}
		});
	}
}