var win = Ti.UI.createWindow({
  backgroundColor: '#fff'
});

var container = Ti.UI.createView({
  height: Ti.UI.SIZE,
  layout: 'vertical'
});

var label1 = Ti.UI.createLabel({
  text: Ti.Locale.currentLanguage + ' (' + L('hello_world') + ')',
  color: 'black'
});

var label2 = Ti.UI.createLabel({
  textid: 'hello_world',
  color: 'black'
});

var btn = Ti.UI.createButton({
  title: 'Change'
});

btn.addEventListener('click', function () {
  var newLang = Ti.Locale.currentLanguage  == 'sv' ? 'en' : 'sv';
  Ti.Locale.setLanguage(newLang);
  label1.text =  Ti.Locale.currentLanguage + ' (' + L('hello_world') + ')';
  label2.textid = 'hello_world';
});

container.add(btn);
container.add(label1);
container.add(label2);
win.add(container);

win.open();



///////// strings.xml for en/////////////////////

<?xml version="1.0" encoding="UTF-8"?><resources>
	<string name="hello_world">This is a test string in English</string>
</resources>


//////////////////

///////// strings.xml for sv/////////////////////

<?xml version="1.0" encoding="UTF-8"?><resources>
	<string name="hello_world">This is a test string in Swedish</string>
</resources>


//////////////////