Don't create extra activity instances from splash screen.

briar-android/src/main/java/org/briarproject/briar/android/login/OpenDatabaseActivity.java

@@ -16,14 +16,10 @@ import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
-import org.briarproject.briar.android.logout.HideUiActivity;
 import org.briarproject.briar.android.navdrawer.NavDrawerActivity;
 
 import javax.inject.Inject;
 
-import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TASK;
-import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
-import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.COMPACTING_DATABASE;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.MIGRATING_DATABASE;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STARTING_SERVICES;
@@ -73,14 +69,6 @@ public class OpenDatabaseActivity extends BriarActivity
 		eventBus.removeListener(this);
 	}
 
-	@Override
-	public void onBackPressed() {
-		Intent i = new Intent(this, HideUiActivity.class);
-		i.addFlags(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TASK);
-		startActivity(i);
-		supportFinishAfterTransition();
-	}
-
 	@Override
 	public void eventOccurred(Event e) {
 		if (e instanceof LifecycleEvent) {
@@ -109,9 +97,7 @@ public class OpenDatabaseActivity extends BriarActivity
 	}
 
 	private void finishAndStartApp() {
-		Intent i = new Intent(this, NavDrawerActivity.class);
+		startActivity(new Intent(this, NavDrawerActivity.class));
-		i.setFlags(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TOP);
-		startActivity(i);
 		supportFinishAfterTransition();
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/splash/SplashScreenActivity.java

@@ -1,5 +1,6 @@
 package org.briarproject.briar.android.splash;
 
+import android.app.Activity;
 import android.content.Intent;
 import android.os.Build;
 import android.os.Bundle;
@@ -8,6 +9,8 @@ import android.support.v7.preference.PreferenceManager;
 import android.transition.Fade;
 
 import org.briarproject.bramble.api.account.AccountManager;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
@@ -19,10 +22,15 @@ import org.briarproject.briar.api.android.LockManager;
 
 import java.util.logging.Logger;
 
+import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
+import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
 import static org.briarproject.briar.android.TestingConstants.EXPIRY_DATE;
 
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 public class SplashScreenActivity extends BaseActivity {
 
 	private static final Logger LOG =
@@ -36,7 +44,7 @@ public class SplashScreenActivity extends BaseActivity {
 	protected AndroidExecutor androidExecutor;
 
 	@Override
-	public void onCreate(Bundle state) {
+	public void onCreate(@Nullable Bundle state) {
 		super.onCreate(state);
 
 		if (Build.VERSION.SDK_INT >= 21) {
@@ -48,16 +56,14 @@ public class SplashScreenActivity extends BaseActivity {
 		setContentView(R.layout.splash);
 
 		if (accountManager.hasDatabaseKey()) {
-			Intent i;
 			if (lockManager.isLocked()) {
 				// The database needs to be opened for the app to be locked.
 				// Start main activity right away. It will open UnlockActivity.
 				// Otherwise, we would end up with two screen unlock inputs.
-				i = new Intent(this, NavDrawerActivity.class);
+				startNextActivity(NavDrawerActivity.class);
 			} else {
-				i = new Intent(this, OpenDatabaseActivity.class);
+				startNextActivity(OpenDatabaseActivity.class);
 			}
-			startActivity(i);
 			finish();
 		} else {
 			new Handler().postDelayed(() -> {
@@ -72,22 +78,28 @@ public class SplashScreenActivity extends BaseActivity {
 		component.inject(this);
 	}
 
-	protected void startNextActivity() {
+	private void startNextActivity() {
 		if (System.currentTimeMillis() >= EXPIRY_DATE) {
 			LOG.info("Expired");
-			startActivity(new Intent(this, ExpiredActivity.class));
+			startNextActivity(ExpiredActivity.class);
 		} else {
 			if (accountManager.accountExists()) {
 				LOG.info("Account exists");
-				startActivity(new Intent(this, OpenDatabaseActivity.class));
+				startNextActivity(OpenDatabaseActivity.class);
 			} else {
 				LOG.info("Account does not exist");
 				accountManager.deleteAccount();
-				startActivity(new Intent(this, SetupActivity.class));
+				startNextActivity(SetupActivity.class);
 			}
 		}
 	}
 
+	private void startNextActivity(Class<? extends Activity> activityClass) {
+		Intent i = new Intent(this, activityClass);
+		i.addFlags(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TOP);
+		startActivity(i);
+	}
+
 	private void setPreferencesDefaults() {
 		androidExecutor.runOnBackgroundThread(() ->
 				PreferenceManager.setDefaultValues(SplashScreenActivity.this,