Introduce ContactExchangeResult

to include all result information in LiveData

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/ContactExchangeActivity.java

@@ -8,13 +8,10 @@ import org.briarproject.bramble.api.keyagreement.KeyAgreementResult;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.activity.ActivityComponent;
 
 import javax.annotation.Nullable;
-import javax.inject.Inject;
 
 import androidx.annotation.UiThread;
-import androidx.lifecycle.ViewModelProvider;
 
 import static android.widget.Toast.LENGTH_LONG;
 import static java.util.Objects.requireNonNull;
@@ -23,40 +20,29 @@ import static java.util.Objects.requireNonNull;
 @ParametersNotNullByDefault
 public class ContactExchangeActivity extends KeyAgreementActivity {
 
-	@Inject
-	ViewModelProvider.Factory viewModelFactory;
-
-	private ContactExchangeViewModel viewModel;
-
-	@Override
-	public void injectActivity(ActivityComponent component) {
-		component.inject(this);
-	}
-
 	@Override
 	public void onCreate(@Nullable Bundle state) {
 		super.onCreate(state);
 		requireNonNull(getSupportActionBar())
 				.setTitle(R.string.add_contact_title);
-		viewModel = new ViewModelProvider(this, viewModelFactory)
-				.get(ContactExchangeViewModel.class);
 	}
 
-	private void startContactExchange(KeyAgreementResult result) {
-		viewModel.getSucceeded().observe(this, succeeded -> {
-			if (succeeded == null) return;
-			if (succeeded) {
-				Author remote = requireNonNull(viewModel.getRemoteAuthor());
-				contactExchangeSucceeded(remote);
-			} else {
-				Author duplicate = viewModel.getDuplicateAuthor();
-				if (duplicate == null) contactExchangeFailed();
-				else duplicateContact(duplicate);
-			}
+	private void startContactExchange(KeyAgreementResult agreementResult) {
+		viewModel.getContactExchangeResult().observe(this, result -> {
+			if (result instanceof ContactExchangeResult.Success) {
+				Author remoteAuthor =
+						((ContactExchangeResult.Success) result).remoteAuthor;
+				contactExchangeSucceeded(remoteAuthor);
+			} else if (result instanceof ContactExchangeResult.Error) {
+				Author duplicateAuthor =
+						((ContactExchangeResult.Error) result).duplicateAuthor;
+				if (duplicateAuthor == null) contactExchangeFailed();
+				else duplicateContact(duplicateAuthor);
+			} else throw new AssertionError();
 		});
-		viewModel.startContactExchange(result.getTransportId(),
-				result.getConnection(), result.getMasterKey(),
-				result.wasAlice());
+		viewModel.startContactExchange(agreementResult.getTransportId(),
+				agreementResult.getConnection(), agreementResult.getMasterKey(),
+				agreementResult.wasAlice());
 	}
 
 	@UiThread

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/ContactExchangeResult.java

@@ -0,0 +1,30 @@
+package org.briarproject.briar.android.contact.add.nearby;
+
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+abstract class ContactExchangeResult {
+
+	static class Success extends ContactExchangeResult {
+		final Author remoteAuthor;
+
+		Success(Author remoteAuthor) {
+			this.remoteAuthor = remoteAuthor;
+		}
+	}
+
+	static class Error extends ContactExchangeResult {
+		@Nullable
+		final Author duplicateAuthor;
+
+		Error(@Nullable Author duplicateAuthor) {
+			this.duplicateAuthor = duplicateAuthor;
+		}
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/ContactExchangeViewModel.java

@@ -8,17 +8,17 @@ import org.briarproject.bramble.api.contact.ContactExchangeManager;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.briar.android.contact.add.nearby.ContactExchangeResult.Error;
+import org.briarproject.briar.android.contact.add.nearby.ContactExchangeResult.Success;
 
 import java.io.IOException;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
-import javax.annotation.Nullable;
 import javax.inject.Inject;
 
 import androidx.annotation.UiThread;
@@ -39,10 +39,8 @@ class ContactExchangeViewModel extends AndroidViewModel {
 	private final Executor ioExecutor;
 	private final ContactExchangeManager contactExchangeManager;
 	private final ConnectionManager connectionManager;
-	private final MutableLiveData<Boolean> succeeded = new MutableLiveData<>();
-
-	@Nullable
-	private volatile Author remoteAuthor, duplicateAuthor;
+	private final MutableLiveData<ContactExchangeResult> exchangeResult =
+			new MutableLiveData<>();
 
 	@Inject
 	ContactExchangeViewModel(Application app, @IoExecutor Executor ioExecutor,
@@ -62,18 +60,16 @@ class ContactExchangeViewModel extends AndroidViewModel {
 				Contact contact = contactExchangeManager.exchangeContacts(conn,
 						masterKey, alice, true);
 				// Reuse the connection as a transport connection
-				connectionManager.manageOutgoingConnection(contact.getId(),
-						t, conn);
-				remoteAuthor = contact.getAuthor();
-				succeeded.postValue(true);
+				connectionManager
+						.manageOutgoingConnection(contact.getId(), t, conn);
+				exchangeResult.postValue(new Success(contact.getAuthor()));
 			} catch (ContactExistsException e) {
 				tryToClose(conn);
-				duplicateAuthor = e.getRemoteAuthor();
-				succeeded.postValue(false);
+				exchangeResult.postValue(new Error(e.getRemoteAuthor()));
 			} catch (DbException | IOException e) {
 				tryToClose(conn);
 				logException(LOG, WARNING, e);
-				succeeded.postValue(false);
+				exchangeResult.postValue(new Error(null));
 			}
 		});
 	}
@@ -87,19 +83,7 @@ class ContactExchangeViewModel extends AndroidViewModel {
 		}
 	}
 
-	@UiThread
-	@Nullable
-	Author getRemoteAuthor() {
-		return remoteAuthor;
-	}
-
-	@UiThread
-	@Nullable
-	Author getDuplicateAuthor() {
-		return duplicateAuthor;
-	}
-
-	LiveData<Boolean> getSucceeded() {
-		return succeeded;
+	LiveData<ContactExchangeResult> getContactExchangeResult() {
+		return exchangeResult;
 	}
 }

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/KeyAgreementActivity.java

@@ -22,10 +22,10 @@ import org.briarproject.bramble.api.plugin.event.TransportStateEvent;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
-import org.briarproject.briar.android.fragment.BaseFragment;
-import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
 import org.briarproject.briar.android.contact.add.nearby.IntroFragment.IntroScreenSeenListener;
 import org.briarproject.briar.android.contact.add.nearby.KeyAgreementFragment.KeyAgreementEventListener;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
 
 import java.util.logging.Logger;
 
@@ -38,6 +38,7 @@ import androidx.appcompat.app.AlertDialog.Builder;
 import androidx.appcompat.widget.Toolbar;
 import androidx.core.app.ActivityCompat;
 import androidx.fragment.app.FragmentManager;
+import androidx.lifecycle.ViewModelProvider;
 
 import static android.Manifest.permission.ACCESS_FINE_LOCATION;
 import static android.Manifest.permission.CAMERA;
@@ -97,12 +98,18 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 	private static final Logger LOG =
 			getLogger(KeyAgreementActivity.class.getName());
 
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
 	@Inject
 	EventBus eventBus;
 
 	@Inject
 	PluginManager pluginManager;
 
+	protected ContactExchangeViewModel viewModel;
+
 	/**
 	 * Set to true in onPostResume() and false in onPause(). This prevents the
 	 * QR code fragment from being shown if onRequestPermissionsResult() is
@@ -140,6 +147,8 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 	@Override
 	public void injectActivity(ActivityComponent component) {
 		component.inject(this);
+		viewModel = new ViewModelProvider(this, viewModelFactory)
+				.get(ContactExchangeViewModel.class);
 	}
 
 	@Override