title: how to define a class on framework(aosp)
body: <p>I want to define my class on frameworks/base/core, and use it as common library.
  So what I did was adding a java class file 'MyTime.java' on frameworks/base/core/java/android/text/format folder. However, when I try to import the class, error 'cannot find symbol' occurred.</p>
  <p>The code of MyTime class is like below.</p>
  <pre><code>package android.text.format;
  ...
  public class MyTime {
      ...
  }
  </code></pre>
  <p>I can't use this class, and tried for days, but still have not found the solution.
  Could anyone help me?</p>