Try to provide hotspot and discover peers at the same time.

app/src/main/java/org/briarproject/publicmesh/MainActivity.java

@@ -59,49 +59,23 @@ public class MainActivity extends AppCompatActivity {
 		((MeshApplication) getApplication()).getAppComponent().inject(this);
 		setContentView(R.layout.activity_main);
 		Button hotspotButton = findViewById(R.id.hotspotButton);
-		Button discoveryButton = findViewById(R.id.discoveryButton);
 		LiveData<Status> hotspotStatus = wifiDirectService.getHotspotStatus();
-		LiveData<Status> discoveryStatus = wifiDirectService.getDiscoveryStatus();
 		hotspotStatus.observe(this, status -> {
 			if (status == STARTING) {
 				hotspotButton.setText(R.string.start_hotspot);
 				hotspotButton.setEnabled(false);
-				discoveryButton.setEnabled(false);
 			} else if (status == STARTED) {
 				hotspotButton.setText(R.string.stop_hotspot);
 				hotspotButton.setEnabled(true);
-				discoveryButton.setEnabled(false);
 			} else if (status == STOPPING) {
 				hotspotButton.setText(R.string.stop_hotspot);
 				hotspotButton.setEnabled(false);
-				discoveryButton.setEnabled(false);
 			} else if (status == STOPPED) {
 				hotspotButton.setText(R.string.start_hotspot);
-				hotspotButton.setEnabled(discoveryStatus.getValue() == STOPPED);
-				discoveryButton.setEnabled(discoveryStatus.getValue() == STOPPED);
-			}
-		});
-		discoveryStatus.observe(this, status -> {
-			if (status == STARTING) {
-				discoveryButton.setText(R.string.start_discovery);
-				discoveryButton.setEnabled(false);
-				hotspotButton.setEnabled(false);
-			} else if (status == STARTED) {
-				discoveryButton.setText(R.string.stop_discovery);
-				discoveryButton.setEnabled(true);
-				hotspotButton.setEnabled(false);
-			} else if (status == STOPPING) {
-				discoveryButton.setText(R.string.stop_discovery);
-				discoveryButton.setEnabled(false);
-				hotspotButton.setEnabled(false);
-			} else if (status == STOPPED) {
-				discoveryButton.setText(R.string.start_discovery);
-				discoveryButton.setEnabled(hotspotStatus.getValue() == STOPPED);
-				hotspotButton.setEnabled(hotspotStatus.getValue() == STOPPED);
+				hotspotButton.setEnabled(true);
 			}
 		});
 		hotspotButton.setOnClickListener(v -> onHotspotButtonClicked());
-		discoveryButton.setOnClickListener(v -> onDiscoveryButtonClicked());
 	}
 
 	@Override
@@ -173,10 +147,4 @@ public class MainActivity extends AppCompatActivity {
 		if (status == STARTED) wifiDirectService.stopHotspot();
 		else if (status == STOPPED) wifiDirectService.startHotspot();
 	}
-
-	private void onDiscoveryButtonClicked() {
-		Status status = wifiDirectService.getDiscoveryStatus().getValue();
-		if (status == STARTED) wifiDirectService.stopDiscovery();
-		else if (status == STOPPED) wifiDirectService.startDiscovery();
-	}
 }
\ No newline at end of file

app/src/main/java/org/briarproject/publicmesh/util/IoUtils.java

@@ -5,18 +5,28 @@ import org.briarproject.publicmesh.nullsafety.NotNullByDefault;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.net.NetworkInterface;
 import java.net.ServerSocket;
 import java.net.Socket;
+import java.net.SocketException;
+import java.util.Enumeration;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
+import static java.util.Collections.emptyList;
+import static java.util.Collections.list;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.publicmesh.util.LogUtils.logException;
 
 @NotNullByDefault
 public class IoUtils {
 
+	private static final Logger LOG = getLogger(IoUtils.class.getName());
+
 	public static void tryToClose(@Nullable Socket s, Logger logger,
 			Level level) {
 		try {
@@ -63,4 +73,16 @@ public class IoUtils {
 		ipBytes[3] = (byte) ((ip >> 24) & 0xFF);
 		return ipBytes;
 	}
+
+	public static List<NetworkInterface> getNetworkInterfaces() {
+		try {
+			Enumeration<NetworkInterface> ifaces =
+					NetworkInterface.getNetworkInterfaces();
+			// Despite what the docs say, the return value can be null
+			return ifaces == null ? emptyList() : list(ifaces);
+		} catch (SocketException e) {
+			logException(LOG, WARNING, e);
+			return emptyList();
+		}
+	}
 }

app/src/main/java/org/briarproject/publicmesh/wifidirect/WifiDirectService.java

@@ -10,12 +10,6 @@ public interface WifiDirectService {
 
 	LiveData<Status> getHotspotStatus();
 
-	void startDiscovery();
-
-	void stopDiscovery();
-
-	LiveData<Status> getDiscoveryStatus();
-
 	enum Status {
 		STARTING,
 		STARTED,

app/src/main/res/layout/activity_main.xml

@@ -11,20 +11,10 @@
 		android:layout_width="wrap_content"
 		android:layout_height="wrap_content"
 		android:text="@string/start_hotspot"
-		app:layout_constraintVertical_chainStyle="packed"
-		app:layout_constraintBottom_toTopOf="@id/discoveryButton"
-		app:layout_constraintLeft_toLeftOf="parent"
-		app:layout_constraintRight_toRightOf="parent"
-		app:layout_constraintTop_toTopOf="parent" />
-
-	<Button
-		android:id="@+id/discoveryButton"
-		android:layout_width="wrap_content"
-		android:layout_height="wrap_content"
-		android:text="@string/start_discovery"
 		app:layout_constraintBottom_toBottomOf="parent"
 		app:layout_constraintLeft_toLeftOf="parent"
 		app:layout_constraintRight_toRightOf="parent"
-		app:layout_constraintTop_toBottomOf="@id/hotspotButton" />
+		app:layout_constraintTop_toTopOf="parent"
+		app:layout_constraintVertical_chainStyle="packed" />
 
 </androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file