title: how to make the Launcher-Pick-Up popup window showing?
body: <p>I have an Launcher app installed. And user has choose another launcher as default, that means when pressing HOME the default launcher will come to front.</p>
  
  <p>I wanna supply user with an convenience of reseting default launcher. Such as a button clicking in my launcher's UI will make Launcher-Pick-Up popup window showing.</p>
  
  <p>Go Launcher can do that(in Go's setting view). it seems Go Launcher does something like "PackageManager.clearPackagePreferredActivities("com.android.launcher")" to clear the prefered launcher activity!</p>
  
  <p>how to achive that ?</p>