android - Open installed application from application -

i have opencv color blob sample installed on device. have application button. when button pressed, trying call opencv color blob open, have had no success. have tried:

public class mainactivity extends activity {  public string packge_name = "org.opencv.samples.colorblobdetect"; public string class_name = "colorblobdetectionactivity";  button bt;  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);     bt = (button) findviewbyid(r.id.button1);     }  public void launchcall() {     // todo auto-generated method stub     intent intent = new intent();     intent.setaction(intent.action_main);     intent.addcategory(intent.category_launcher);         intent.setcomponent(new componentname(packge_name, class_name));     startactivity(intent);     }          } 

then have xml

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:paddingbottom="@dimen/activity_vertical_margin"     android:paddingleft="@dimen/activity_horizontal_margin"     android:paddingright="@dimen/activity_horizontal_margin"     android:paddingtop="@dimen/activity_vertical_margin"     tools:context=".mainactivity" >          <button         android:id="@+id/button1"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignparentleft="true"         android:layout_alignparenttop="true"         android:onclick="launchcall"         android:text="call other app" />         </relativelayout> 

how can open application application?

intent launchintent = getpackagemanager().getlaunchintentforpackage("com.package.address"); startactivity(launchintent);