title: How to prevent user input?
body: <p>My <code>activity_main.xml</code>'s interface is <strong>shared</strong> by <code>MainActivity.java</code> (which contains the actual code for buttons), and <code>SecondActivity.java</code>. </p>
  
  <p>The problem is , It would let the user play around with the buttons, when they are in <code>MainActivity</code>, but If they are in <code>SecondActivity</code>, and they were to press a button, It would crash my app, because It doesn't have the code for the buttons.</p>
  
  <p>So how do I prevent user clicking the screen in <code>SecondActivity</code>?</p>