Show a snackbar when a peer connected to the hotspot

briar-android/src/main/java/org/briarproject/briar/android/hotspot/HotspotFragment.java

@@ -3,8 +3,12 @@ package org.briarproject.briar.android.hotspot;
 import android.os.Bundle;
 import android.view.View;
 
+import com.google.android.material.snackbar.Snackbar;
+
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 
 import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
@@ -20,12 +24,9 @@ public class HotspotFragment extends AbstractTabsFragment {
 	@Override
 	public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
 		super.onViewCreated(view, savedInstanceState);
-		// no need to call into the ViewModel here
-		connectedButton.setOnClickListener(v -> {
-			Fragment f = new WebsiteFragment();
-			String tag = WebsiteFragment.TAG;
-			showFragment(getParentFragmentManager(), f, tag);
-		});
+		connectedButton.setOnClickListener(v -> showNextFragment());
+		viewModel.getPeerConnectedEvent().observeEvent(getViewLifecycleOwner(),
+				this::onPeerConnected);
 	}
 
 	@Override
@@ -38,4 +39,21 @@ public class HotspotFragment extends AbstractTabsFragment {
 		return QrHotspotFragment.newInstance(true);
 	}
 
+	private void onPeerConnected(boolean connected) {
+		if (!connected) return;
+		new BriarSnackbarBuilder()
+				.setAction(R.string.hotspot_peer_connected_action, v ->
+						showNextFragment())
+				.make(connectedButton, R.string.hotspot_peer_connected,
+						Snackbar.LENGTH_LONG)
+				.setAnchorView(connectedButton)
+				.show();
+	}
+
+	private void showNextFragment() {
+		Fragment f = new WebsiteFragment();
+		String tag = WebsiteFragment.TAG;
+		showFragment(getParentFragmentManager(), f, tag);
+	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/hotspot/HotspotManager.java

@@ -45,6 +45,9 @@ class HotspotManager implements ActionListener {
 		@IoExecutor
 		void onHotspotStarted(NetworkConfig networkConfig);
 
+		@UiThread
+		void onDeviceConnected();
+
 		void onHotspotStopped();
 
 		void onHotspotError(String error);
@@ -216,6 +219,7 @@ class HotspotManager implements ActionListener {
 			}
 		};
 		try {
+			if (channel == null) return;
 			wifiP2pManager.requestGroupInfo(channel, groupListener);
 		} catch (SecurityException e) {
 			// this should never happen, because we request permissions before
@@ -223,6 +227,7 @@ class HotspotManager implements ActionListener {
 		}
 	}
 
+	@UiThread
 	private void onHotspotStarted(WifiP2pGroup group) {
 		DisplayMetrics dm = ctx.getResources().getDisplayMetrics();
 		ioExecutor.execute(() -> {
@@ -233,6 +238,7 @@ class HotspotManager implements ActionListener {
 					group.getPassphrase(), qrCode);
 			listener.onHotspotStarted(config);
 		});
+		requestGroupInfoForConnection();
 	}
 
 	private boolean isGroupValid(@Nullable WifiP2pGroup group) {
@@ -268,6 +274,30 @@ class HotspotManager implements ActionListener {
 		}
 	}
 
+	@UiThread
+	private void requestGroupInfoForConnection() {
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("requestGroupInfo for connection");
+		}
+		GroupInfoListener groupListener = group -> {
+			if (group == null || group.getClientList().isEmpty()) {
+				handler.postDelayed(this::requestGroupInfoForConnection,
+						RETRY_DELAY_MILLIS);
+			} else {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("client list " + group.getClientList());
+				}
+				listener.onDeviceConnected();
+			}
+		};
+		try {
+			if (channel == null) return;
+			wifiP2pManager.requestGroupInfo(channel, groupListener);
+		} catch (SecurityException e) {
+			throw new AssertionError(e);
+		}
+	}
+
 	private static String createWifiLoginString(String ssid, String password) {
 		// https://en.wikipedia.org/wiki/QR_code#WiFi_network_login
 		// do not remove the dangling ';', it can cause problems to omit it

briar-android/src/main/java/org/briarproject/briar/android/hotspot/HotspotViewModel.java

@@ -17,6 +17,8 @@ import org.briarproject.briar.android.hotspot.HotspotState.StartingHotspot;
 import org.briarproject.briar.android.hotspot.HotspotState.WebsiteConfig;
 import org.briarproject.briar.android.hotspot.WebServerManager.WebServerListener;
 import org.briarproject.briar.android.viewmodel.DbViewModel;
+import org.briarproject.briar.android.viewmodel.LiveEvent;
+import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 
 import java.security.SecureRandom;
@@ -47,6 +49,8 @@ class HotspotViewModel extends DbViewModel
 
 	private final MutableLiveData<HotspotState> state =
 			new MutableLiveData<>();
+	private final MutableLiveEvent<Boolean> peerConnected =
+			new MutableLiveEvent<>();
 
 	@Nullable
 	// Field to temporarily store the network config received via onHotspotStarted()
@@ -109,6 +113,12 @@ class HotspotViewModel extends DbViewModel
 		webServerManager.startWebServer();
 	}
 
+	@UiThread
+	@Override
+	public void onDeviceConnected() {
+		peerConnected.setEvent(true);
+	}
+
 	@Override
 	public void onHotspotStopped() {
 		LOG.info("stopping webserver");
@@ -141,4 +151,8 @@ class HotspotViewModel extends DbViewModel
 		return state;
 	}
 
+	LiveEvent<Boolean> getPeerConnectedEvent() {
+		return peerConnected;
+	}
+
 }

briar-android/src/main/res/layout/fragment_error.xml

@@ -49,6 +49,6 @@
 		app:layout_constraintEnd_toEndOf="parent"
 		app:layout_constraintStart_toStartOf="parent"
 		app:layout_constraintTop_toBottomOf="@+id/errorTitle"
-		tools:text="@string/qr_code_unsupported" />
+		tools:text="@string/startup_failed_service_error" />
 
 </androidx.constraintlayout.widget.ConstraintLayout>

briar-android/src/main/res/values/strings.xml

@@ -721,6 +721,8 @@
 	<string name="hotspot_manual_wifi">To download the app on another phone, please connect to this Wi-Fi network:</string>
 	<string name="hotspot_manual_wifi_ssid">Network name (SSID)</string>
 	<string name="hotspot_manual_wifi_alt">Instead of adding the network manually, you can also scan a QR code.</string>
+	<string name="hotspot_peer_connected">Successfully connected</string>
+	<string name="hotspot_peer_connected_action">Show download info</string>
 	<string name="hotspot_manual_site">After you are connected to the Wi-Fi, carefully enter this address in your browser.</string>
 	<string name="hotspot_manual_site_address">Address (URL)</string>
 	<string name="hotspot_manual_site_alt">Instead of typing the address manually, you can also scan a QR code.</string>