title: Start activity from another package
body: <p>I have this manifest:</p>
  
  <pre><code>&lt;manifest ...
      package="com.my"&gt;
  
      &lt;application ...&gt;
  
          &lt;activity ...
              android:name=".app.Run"&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;
  
      &lt;activity ...
      android:name=".app.Preferences"/&gt;
  
      &lt;activity ...
      android:name=".library.error.ErrorDialog"/&gt;
  
      &lt;/application&gt;
  
  &lt;/manifest&gt;
  </code></pre>
  
  <p>How can I start <code>ErrorDialog</code> activity from <code>Run</code> activity?</p>
  
  <pre><code>Intent intent = new Intent();
  intent.setComponent(new ComponentName("com.my.library.error", "com.my.library.error.ErrorDialog"));
  startActivity(intent);
  </code></pre>
  
  <p>Or  </p>
  
  <pre><code>Intent intent = new Intent();
  intent.setComponent(new ComponentName("library.error", "library.error.ErrorDialog"));
  startActivity(intent);
  </code></pre>
  
  <p>Not working</p>
  
  <hr>
  
  <p><strong>MEA CULPA... MEA CULPA...</strong></p>
  
  <p>My <code>ErrorDialog</code> Activity was not public. :D</p>