NotEnoughItems/src/codechicken/nei/ItemQuantityField.java

package codechicken.nei;

public class ItemQuantityField extends TextField
{
    public ItemQuantityField(String ident) {
        super(ident);
        centered = true;
    }

    @Override
    public boolean isValid(String string) {
        if (string.equals(""))
            return true;

        try {
            return Integer.parseInt(string) >= 0;
        } catch (NumberFormatException nfe) {
            return false;
        }
    }

    public int intValue() {
        return intValue(text());
    }

    public int intValue(String s) {
        try {
            return Integer.parseInt(s);
        } catch (NumberFormatException nfe) {
            return 0;
        }
    }

    @Override
    public void loseFocus() {
        setText(Integer.toString(NEIClientConfig.getItemQuantity()));
    }

    @Override
    public void onTextChange(String oldText) {
        if (intValue(oldText) != intValue())//hacky recursion stopper
            NEIClientUtils.setItemQuantity(intValue());
    }
}