code: public static boolean isPackageInstalled(Context context, String packageName) {
  		try {
  			context.getPackageManager().getApplicationInfo(packageName, 0);
  			return true;
  		} catch (Exception e) {
  			return false;
  		}
  	}
docs: Checks if a package is installed.
  
  @param context Context to be used to verify the existence of the package.
  @param packageName Package name to be searched.
  @return true if the package is discovered; false otherwise