public static boolean isInstalled(@NonNull final String packageName) {
        return isLaunchable(packageName) || hasPackageInstalled(packageName);
    }
Checks whether a launch intent is available or if the package is just installed
This function is relatively costly, so if you know that the package in question has
a launch intent, use isLaunchable() instead.
main/src/main/java/cgeo/geocaching/utils/ProcessUtils.java