Code Block :
 
//Define the current window
var currentWin = Ti.UI.currentWindow;
 
//Define a label
var messageLbl = Ti.UI.createLabel({
      width   : '100dp',      //assign the width with dp values
      height  : '20dp',       //assign the height with dp values
      top      : '20dp',       //assign the top position with dp values 
      left      : '10dp',       // assign the left position with dp values
      text     : 'Hi! this is a label control'
});
 
//Label added to the window
currentWin.add(messageLbl);
 
//Define a button
var  sampleButton = Ti.UI.createButton({
     width     : '50%',      //assign the width with % values
      height   : '10%',       //assign the height with % values
      bottom  : '20%',       //assign the bottom position with % values 
      right     : '10%',       // assign the right position with % values
      title      : 'Hi! this is a button control'
});
 
//Button added to the window
currentWin.add(sampleButton);

I have tested it with different resolutions of Android devices.