title: import android packages cannot be resolved
body: <p>My android application, built inside Eclipse, suddenly fails to build with dozens of errors.  The most obvious are errors indicating that all the android imports cannot be resolved.</p>
  
  <pre><code>import android.os.Bundle;
  import android.app.Activity;
  import android.graphics.drawable.Drawable;
  import android.media.AudioManager;
  import android.util.Log;
  import android.view.Menu;
  import android.view.View;
  import android.widget.Button;
  import android.widget.ImageView;
  </code></pre>
  
  <p>All of these are flagged as unresolvable.  I've tried removing and re-adding the JRE System Library.  I've tried cleaning and rebuilding.  I've tried the "Quick fix" option to "Fix Project Setup..." but that simply responds with a dialog box that say...</p>
  
  <p>"<strong>No proposals have been found to fix the unresolvable reference to 'android.app.Bundle'.  Click here to manually configure the build path of project 'Silent Mode Toggle."</strong></p>
  
  <p>I'm new to Android development and this one has me completely stumped.</p>
  
  <p>Thanks in advance for any help you can provide.</p>
  
  <p>Rich</p>