display explainer screen when choosing recover account

briar-android/src/main/java/org/briarproject/briar/android/account/NewOrRecoverActivity.java

@@ -42,6 +42,7 @@ public class NewOrRecoverActivity extends BaseActivity implements
 		startActivity(i);
 	}
 
+	@Override
 	public void recoverAccountChosen() {
 		finish();
 		Intent i = new Intent(this, RecoverActivity.class);
@@ -51,7 +52,8 @@ public class NewOrRecoverActivity extends BaseActivity implements
 	}
 
 	@Override
+	@Deprecated
 	public void runOnDbThread(Runnable runnable) {
-
+		throw new RuntimeException("Don't use this deprecated method here.");
 	}
 }

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/ExplainerDismissedListener.java

@@ -0,0 +1,8 @@
+package org.briarproject.briar.android.socialbackup;
+
+import androidx.annotation.UiThread;
+
+public interface ExplainerDismissedListener {
+	@UiThread
+	void explainerDismissed();
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/OwnerRecoveryModeExplainerFragment.java

@@ -1,5 +1,6 @@
 package org.briarproject.briar.android.socialbackup;
 
+import android.content.Context;
 import android.os.Bundle;
 
 import android.view.LayoutInflater;
@@ -16,6 +17,7 @@ import androidx.annotation.Nullable;
 
 public class OwnerRecoveryModeExplainerFragment extends BaseFragment {
 
+	protected ExplainerDismissedListener listener;
 	public static final String TAG =
 			OwnerRecoveryModeExplainerFragment.class.getName();
 
@@ -32,14 +34,18 @@ public class OwnerRecoveryModeExplainerFragment extends BaseFragment {
 			@Nullable Bundle savedInstanceState) {
 		View view = inflater.inflate(R.layout.fragment_recovery_owner_explainer,
 				container, false);
-//		Button button = view.findViewById(R.id.button);
-//		button.setOnClickListener(e -> {
-//			listener.shardsSentDismissed();
-//		});
+		Button button = view.findViewById(R.id.beginButton);
+		button.setOnClickListener(e -> listener.explainerDismissed());
 
 		return view;
 	}
 
+	@Override
+	public void onAttach(Context context) {
+		super.onAttach(context);
+		listener = (ExplainerDismissedListener) context;
+	}
+
 	@Override
 	public void injectFragment(ActivityComponent component) {
 		component.inject(this);

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/RecoverActivity.java

@@ -1,25 +1,42 @@
 package org.briarproject.briar.android.socialbackup;
 
 import android.os.Bundle;
+import android.widget.Toast;
 
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BaseActivity;
 import org.briarproject.briar.android.activity.BriarActivity;
 import org.briarproject.briar.android.fragment.BaseFragment;
 
-public class RecoverActivity extends BriarActivity implements
-		BaseFragment.BaseFragmentListener {
+public class RecoverActivity extends BaseActivity implements
+		BaseFragment.BaseFragmentListener, ExplainerDismissedListener {
 
 	@Override
 	public void onCreate(Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
 		setContentView(R.layout.activity_recover);
-
 		OwnerRecoveryModeExplainerFragment fragment = new OwnerRecoveryModeExplainerFragment();
 		showInitialFragment(fragment);
 	}
+
 	@Override
 	public void injectActivity(ActivityComponent component) {
 		component.inject(this);
 	}
+
+	@Override
+	public void explainerDismissed () {
+		Toast.makeText(this,
+				"coming soon...",
+				Toast.LENGTH_SHORT).show();
+		// TODO go to the next screen in the recover process
+		finish();
+	}
+
+	@Override
+	@Deprecated
+	public void runOnDbThread(Runnable runnable) {
+		throw new RuntimeException("Don't use this deprecated method here.");
+	}
 }

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

@@ -34,7 +34,7 @@
 		app:srcCompat="@drawable/qr_code_intro" />
 
 	<Button
-		android:id="@+id/button"
+		android:id="@+id/beginButton"
 		android:layout_width="match_parent"
 		android:layout_height="wrap_content"
 		android:layout_marginTop="24dp"