NumberTextWatcher.java

import java.text.DecimalFormat;
import java.text.ParseException;

import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;

public class NumberTextWatcher implements TextWatcher {
    
    private DecimalFormat df;
    private DecimalFormat dfnd;
    private boolean hasFractionalPart;    
    
    private EditText et;
    
    public NumberTextWatcher(EditText et)
    {
		df = new DecimalFormat("#,###.##");
		df.setDecimalSeparatorAlwaysShown(true);
		dfnd = new DecimalFormat("#,###");
		
		this.et = et;
		hasFractionalPart = false;
    }
    
    @Override
	public void afterTextChanged(Editable s)
    {
		et.removeTextChangedListener(this);
		
		try {
		    
			int inilen, endlen;
		    inilen = et.getText().length();
		    
		    String v = s.toString().replace(String.valueOf(df.getDecimalFormatSymbols().getGroupingSeparator()), "");
		    Number n = df.parse(v);
		    
		    int cp = et.getSelectionStart();
		    
		    if (hasFractionalPart) {
		    	et.setText(df.format(n));
		    } else {
		    	et.setText(dfnd.format(n));
		    }
		    
		    endlen = et.getText().length();
		    int sel = (cp + (endlen - inilen));
		    if (sel > 0 && sel <= et.getText().length()) {
		    	et.setSelection(sel);
		    } else {
				// place cursor at the end?
				et.setSelection(et.getText().length() - 1);
		    }
		    
		} catch (NumberFormatException nfe) {
		    // do nothing?
		} catch (ParseException e) {
		    // do nothing?
		}
		
		et.addTextChangedListener(this);
    }

    @Override
	public void beforeTextChanged(CharSequence s, int start, int count, int after)
    {
    }

    @Override
	public void onTextChanged(CharSequence s, int start, int before, int count)
    {
    	if (s.toString().contains(String.valueOf(df.getDecimalFormatSymbols().getDecimalSeparator())))
	    {
    		hasFractionalPart = true;
	    } else {
	    	hasFractionalPart = false;
	    }
    }

}