java - 如何在没有 Activity 的情况下知道 Android VPN 准备何时准备就绪？

Question

当您想启动 Vpn 时，我们可以这样做：

VpnService.prepare(activity)

然后 ：

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data)
    if (requestCode == REQUEST_VPN && resultCode == AppCompatActivity.RESULT_OK) {
 
        }

    }
}

但我们是在活动之外做的，我是这样做的：

private void setupVPN() {
     if (vpnInterface == null) {

         jni_context = jni_init(Build.VERSION.SDK_INT);
        Builder builder = new Builder();
        builder.addAddress(VPN_ADDRESS, 1);

        vpnInterface = getBuilder().establish();//.setSession(getString(R.string.app_name)).setConfigureIntent(pendingIntent).establish();

        if (vpnInterface != null) {
             startNative();
        } else {
            // vpn failed to establish, prepare may not call or called but not yey prepared,
            // we will try 3 times or destroy vpn
            Timber.e("vpnInterface failed to establish");
            vpnSetupAttempts++;
            if (vpnSetupAttempts < 4) {
                VpnService.prepare(this);
                final Handler handler = new Handler(Looper.getMainLooper());
                handler.postDelayed(this::setupVPN, 2000);
            } else {
                vpnSetupAttempts = 0;
                logNonFatalException("vpnInterface failed to establish");
                stopVpn();

            }
        }

    }
}

所以基本上我正在等待 VPN 准备好而没有任何指示，这是可行的，但感觉不是一个好习惯，当 VPN 准备好时，还有其他方法可以收听吗？某种监听器？