Detecting if an app is installed and still installed on Android device

Hello,

I'm using this code to launch another unity game from within my game. This code detects if the the other game is installed and launch it. The problem is if I uninstalled it will detect that it is still installed! How do I fix this?

 AndroidJavaClass up = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
 AndroidJavaObject ca = up.GetStatic<AndroidJavaObject>("currentActivity");
 AndroidJavaObject packageManager = ca.Call<AndroidJavaObject>("getPackageManager");
 AndroidJavaObject launchIntent = null;
 //if the app is installed, no errors. Else, doesn't get past next line
 try
 {
     launchIntent = packageManager.Call<AndroidJavaObject>("getLaunchIntentForPackage", currentGameInfo.bundleId);
     if (launchIntent != null)
         ca.Call("startActivity", launchIntent);
 }
 catch (Exception ex)
 {
 }