为什么网络发现服务（NSD）发现但无法解析多个服务？

Question

我遇到了这个问题，无法解决。我正在使用NSD Android API查找网络上的多个服务。问题是，如果网络中只有一台具有该服务类型的设备，我可以检测到它并解决它，但是如果有不止一次，我可以检测到它，但是没有一个可以解决。

我在互联网上读到一些人也遇到过同样的问题，他们建议每次尝试解析服务时都创建新的onResolveListener。我也为DiscoveryListener做过，但似乎无法解决多个服务问题。

如果您有任何建议或示例，请提前谢谢！

public class MainActivity extends AppCompatActivity {

private String SERVICE_NAME = "printer";
private String SERVICE_TYPE = "_print._tcp.";


private InetAddress hostAddress;
private int hostPort;
private NsdManager mNsdManager;
NsdServiceInfo mService;
private WebView mWebView;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    //Getting toolbar by id
    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);


    //disabling default title text
    getSupportActionBar().setDisplayShowTitleEnabled(false);

    mWebView = findViewById(R.id.activity_main_webview);

    //Enable JavasScript for webView

    WebSettings webSettings = mWebView.getSettings();
    webSettings.setJavaScriptEnabled(true);
    mWebView.setWebViewClient(new WebViewClient());

    //mWebView.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);

    mWebView.getSettings().setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NORMAL);
    mWebView.getSettings().setLoadWithOverviewMode(true);
    mWebView.getSettings().setUseWideViewPort(true);
    mWebView.getSettings().setBuiltInZoomControls(true);
    mWebView.getSettings().setSupportZoom(true);

    getWindow().setFlags(WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED,
            WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED);

    if (Build.VERSION.SDK_INT >= 19) {
        mWebView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
    } else {
        mWebView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
    }

    //NSD stuff

    mNsdManager = (NsdManager) getSystemService(Context.NSD_SERVICE);
    mNsdManager.discoverServices(SERVICE_TYPE, NsdManager.PROTOCOL_DNS_SD, mDiscoveryListener);

}

@Override
public void onBackPressed() {
    if (mWebView.canGoBack() && mWebView.isFocused()) {
        mWebView.goBack();
    } else {
        super.onBackPressed();
    }
}



NsdManager.DiscoveryListener mDiscoveryListener = new NsdManager.DiscoveryListener() {
    @Override
    public void onStartDiscoveryFailed(String serviceType, int errorCode) {
        Log.e("TAG", "DiscoveryFailed: Error code: " + errorCode);
        mNsdManager.stopServiceDiscovery(this);

    }

    @Override
    public void onStopDiscoveryFailed(String serviceType, int errorCode) {
        Log.e("TAG", "Discovery failed : Error code: " + errorCode);
        mNsdManager.stopServiceDiscovery(this);
    }

    @Override
    public void onDiscoveryStarted(String regType) {
        Log.d("TAG", "Service discovery started");

    }

    @Override
    public void onDiscoveryStopped(String serviceType) {
        Log.i("TAG", "Discovery stopped: " + serviceType);

    }

    @Override
    public void onServiceFound(final NsdServiceInfo serviceInfo) {

        Log.d("TAG", "Service discovery success : " + serviceInfo);
        Log.d("TAG", "Host = " + serviceInfo.getServiceName());
        Log.d("TAG", "Port = " + serviceInfo.getPort());

        if (serviceInfo.getServiceType().equals(SERVICE_TYPE)) {
            Log.d("TAG", "Unknown Service Type: " + serviceInfo.getServiceType());


            mNsdManager.resolveService(serviceInfo, new NsdManager.ResolveListener() {
                @Override
                public void onResolveFailed(NsdServiceInfo nsdServiceInfo, int errorCode) {
                    Log.e("TAG", "Resolve failed: " + nsdServiceInfo);

                }


                @Override
                public void onServiceResolved(NsdServiceInfo nsdServiceInfo) {

                    final String nsdServiceInfoName = nsdServiceInfo.getServiceName();
                    final TextView myTextView = findViewById(R.id.serviceName);

                    /*
                    CountDownLatch latch = new CountDownLatch(1);
                    mNsdManager.discoverServices(SERVICE_TYPE, NsdManager.PROTOCOL_DNS_SD,mDiscoveryListener);
                    try {
                        latch.await();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    mNsdManager.discoverServices(SERVICE_TYPE,NsdManager.PROTOCOL_DNS_SD,mDiscoveryListener);


                    latch.countDown();
                    */


                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            myTextView.setText(nsdServiceInfoName);
                            myTextView.setOnClickListener(new View.OnClickListener() {
                                @Override
                                public void onClick(View view) {
                                    //Toast.makeText(MainActivity.this, "im printer",Toast.LENGTH_SHORT).show();
                                    mWebView.loadUrl("http://10.0.0.115");

                                }
                            });

                        }
                    });

                    Log.d("TAG", "Resolve Succeeded " + nsdServiceInfo);

                    if (nsdServiceInfo.getServiceType().equals(SERVICE_TYPE)) {
                        Log.d("TAG", "Same IP");
                        return;
                    }

                    hostPort = nsdServiceInfo.getPort();
                    hostAddress = nsdServiceInfo.getHost();
                }

            });

        }
    }

    @Override
    public void onServiceLost(NsdServiceInfo nsdServiceInfo) {

        Log.d("TAG", "Service lost " + nsdServiceInfo);
    }

};
}

我得到的错误是“解决失败，服务名称”