how to install apk file programmatically

Intent intent = new Intent(Intent.ACTION_VIEW);
    intent.setDataAndType(Uri.fromFile(new File
            (Environment.getExternalStorageDirectory()  + "/barcode.apk")), "application/vnd.android.package-archive");
    startActivity(intent);

It probably will not work with an android.resource Uri. Try copying the APK out to external storage and doing the install from there.