How to properly save data across Activities. savedInstanceState always appears to be null
<p>I have 2 activities A and B.</p>

<ol>
<li>I call activity B from activity A using startActivity(B);</li>
<li>I do some operations in B and call back activity A using startActivity(A);</li>
</ol>

<p>I have noticed that instance variables in class A are cleared (reinitialized). Is using <code>onSaveInstanceState(Bundle)</code> a correct way to save these variables before A gets stopped?</p>

<p>In my <code>onCreate(Bundle savedInstanceState)</code> method of class A, I try to retrieve the data previously saved by <code>onSaveInstanceState(Bundle)</code>. However the variable <code>savedInstanceState</code> is always null and I can't retrieve any data.</p>
