title: android.content.ActivityNotFoundException: Unable to find explicit activity class {}; have you declared this activity in your AndroidManifest.xml?
body: <p>This is the scenario: i have <strong>2 diferent package in the same proyect.</strong>
  When i try to launch vía intent <strong>ActivityB (which is in com.stable.app.in)</strong> from package <strong>com.stable.app ActivityA</strong>, i get this error. My Manifest is OK i guess, but seems to be wrong. My Manifest is:</p>
  
  <pre><code>&lt;activity android:name=".in.Principal"&gt;
     &lt;intent-filter&gt;
       &lt;action android:name="android.intent.action.MAIN" /&gt;
       &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
     &lt;/intent-filter&gt;
  &lt;/activity&gt;
  </code></pre>
  
  <p>And my code is:</p>
  
  <pre><code>final Intent intent = new Intent();                
  intent.setClassName("com.stable.app.in", "com.stable.app.in.Principal");
  intent.setAction(Intent.ACTION_MAIN);
  intent.addCategory(Intent.CATEGORY_LAUNCHER);
  startActivity(intent);
  </code></pre>
  
  <p>I have tried a lot of suggestions seemed in other topics. Those are: 
  Give to Manifest the whole route of the package.
  try to cut out MAIN, LAUNCHER, etc.
  a lot more.</p>
  
  <p>If you have had the same problem, or have a potencional solution, dont hasitate to respond!</p>