Android：检查应用程序安装成功的时间

Question

如何检查android中的应用是否已成功安装？还有其他方法

private boolean isInstalled(String pack) {
    PackageManager pm = getPackageManager();
    boolean app_installed = false;
    try {
        pm.getPackageInfo(pack, PackageManager.GET_ACTIVITIES);
        app_installed = true;
    } catch (PackageManager.NameNotFoundException e) {
        app_installed = false;
    }
    return app_installed;
}