Navigator as ViewModel pattern

app/build.gradle

@@ -84,6 +84,7 @@ dependencies {
     implementation 'com.ryanharter.auto.value:auto-value-parcel-adapter:0.2.6'
 
     implementation "android.arch.lifecycle:extensions:1.1.1"
+
     annotationProcessor "android.arch.lifecycle:compiler:1.1.1"
     implementation 'com.android.support:appcompat-v7:27.1.1'
 

app/src/main/java/org/sagebionetworks/research/app/MainActivity.java

@@ -57,7 +57,7 @@ protected void onCreate(Bundle savedInstanceState) {
                     .build();
         }
         if (performTaskFragment == null) {
-            performTaskFragment = PerformTaskFragment.newInstance(taskView);
+            performTaskFragment = PerformTaskFragment.newInstance("taskId");
 
             getSupportFragmentManager()
                     .beginTransaction()

data/src/main/java/org/sagebionetworks/research/data/FakeTaskRepository.java

@@ -38,6 +38,7 @@
 import org.sagebionetworks.research.data.model.step.ConcreteUIStep;
 import org.sagebionetworks.research.domain.Schema;
 import org.sagebionetworks.research.domain.repository.TaskRepository;
+import org.sagebionetworks.research.domain.result.TaskResult;
 import org.sagebionetworks.research.domain.step.Step;
 import org.sagebionetworks.research.domain.step.ui.UIStep;
 import org.sagebionetworks.research.domain.task.Task;
@@ -47,14 +48,12 @@
 import java.util.List;
 import java.util.UUID;
 
+import io.reactivex.Completable;
 import io.reactivex.Single;
 import javax.inject.Inject;
 
 public class FakeTaskRepository implements TaskRepository {
-    @Inject
-    public FakeTaskRepository() {
-    }
-
+    @Inject public FakeTaskRepository() {}
     @Override
     public Single<Task> getTask(final String taskIdentifier) {
         return Single.<Task>just(new Task() {
@@ -106,6 +105,12 @@ public Single<List<Step>> getTaskSteps(final Task task) {
         ));
     }
 
+    @NonNull
+    @Override
+    public Completable setTaskResult(final TaskResult taskResult) {
+        return Completable.error(new UnsupportedOperationException("Not implemented yet"));
+    }
+
     private UIStep createUIStep(String id) {
         return ConcreteUIStep.builder()
                 .setIdentifier(id)

domain/src/main/java/org/sagebionetworks/research/domain/repository/TaskRepository.java

@@ -32,13 +32,16 @@
 
 package org.sagebionetworks.research.domain.repository;
 
+import android.support.annotation.CheckResult;
 import android.support.annotation.NonNull;
 
+import org.sagebionetworks.research.domain.result.TaskResult;
 import org.sagebionetworks.research.domain.step.Step;
 import org.sagebionetworks.research.domain.task.Task;
 
 import java.util.List;
 
+import io.reactivex.Completable;
 import io.reactivex.Single;
 
 public interface TaskRepository {
@@ -47,4 +50,8 @@ public interface TaskRepository {
 
     @NonNull
     Single<List<Step>> getTaskSteps(Task task);
+
+    @NonNull
+    @CheckResult
+    Completable setTaskResult(TaskResult taskResult);
 }

domain/src/test/java/org/sagebionetworks/research/domain/task/navigation/strategy/next_step/ConstantNextStepStrategyTest.java

@@ -37,7 +37,7 @@
 import org.sagebionetworks.research.domain.task.navigation.strategy.StepNavigationStrategy.NextStepStrategy;
 
 import static org.junit.Assert.*;
-import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.*;
 
 public class ConstantNextStepStrategyTest {
 

mobile-ui/build.gradle

@@ -91,6 +91,7 @@ dependencies {
     implementation 'android.arch.lifecycle:extensions:1.1.1'
     annotationProcessor "android.arch.lifecycle:compiler:1.1.1"
     testImplementation 'junit:junit:4.12'
+    testImplementation "android.arch.core:core-testing:1.1.1"
     androidTestImplementation 'com.android.support.test:runner:1.0.1'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
 }

mobile-ui/src/main/java/org/sagebionetworks/research/mobile_ui/mapper/TaskMapper.java

@@ -32,5 +32,10 @@
 
 package org.sagebionetworks.research.mobile_ui.mapper;
 
+import javax.inject.Inject;
+
 public class TaskMapper {
+    @Inject
+    public TaskMapper() {
+    }
 }

mobile-ui/src/main/java/org/sagebionetworks/research/mobile_ui/perform_task/PerformTaskFragment.java

@@ -43,15 +43,15 @@
 import android.view.View;
 import android.view.ViewGroup;
 
+import com.google.common.base.Strings;
+
 import org.sagebionetworks.research.domain.mobile_ui.R;
 import org.sagebionetworks.research.mobile_ui.mapper.StepMapper;
-import org.sagebionetworks.research.mobile_ui.show_step.StepPresenter;
 import org.sagebionetworks.research.mobile_ui.show_step.StepPresenterFactory;
 import org.sagebionetworks.research.mobile_ui.show_step.view.ShowStepFragment;
 import org.sagebionetworks.research.mobile_ui.show_step.view.ShowStepFragmentBase;
 import org.sagebionetworks.research.presentation.model.StepView;
 import org.sagebionetworks.research.presentation.model.StepView.NavDirection;
-import org.sagebionetworks.research.presentation.model.TaskView;
 import org.sagebionetworks.research.presentation.perform_task.PerformTaskViewModel;
 import org.sagebionetworks.research.presentation.perform_task.PerformTaskViewModelFactory;
 
@@ -70,7 +70,7 @@
  * A placeholder fragment containing a simple view.
  */
 public class PerformTaskFragment extends Fragment implements HasSupportFragmentInjector {
-    private static final String ARGUMENT_TASK_VIEW = "TASK_VIEW";
+    private static final String ARGUMENT_TASK_IDENTIFIER = "TASK_VIEW";
 
     @Inject
     DispatchingAndroidInjector<Fragment> fragmentDispatchingAndroidInjector;
@@ -88,17 +88,15 @@ public class PerformTaskFragment extends Fragment implements HasSupportFragmentI
 
     private PerformTaskViewModel performTaskViewModel;
 
-    private StepPresenter stepPresenter;
-
-    private TaskView taskView;
+    private String taskIdentifier;
 
     private Unbinder unbinder;
 
-    public static PerformTaskFragment newInstance(@NonNull TaskView taskView) {
-        checkNotNull(taskView);
+    public static PerformTaskFragment newInstance(@NonNull String taskIdentifier) {
+        checkNotNull(taskIdentifier);
 
         Bundle arguments = new Bundle();
-        arguments.putParcelable(ARGUMENT_TASK_VIEW, taskView);
+        arguments.putString(ARGUMENT_TASK_IDENTIFIER, taskIdentifier);
 
         PerformTaskFragment fragment = new PerformTaskFragment();
         fragment.setArguments(arguments);
@@ -119,14 +117,14 @@ public void onCreate(Bundle savedInstanceState) {
         if (savedInstanceState == null) {
             Bundle arguments = getArguments();
             if (arguments != null) {
-                taskView = getArguments().getParcelable(ARGUMENT_TASK_VIEW);
+                taskIdentifier = getArguments().getString(ARGUMENT_TASK_IDENTIFIER);
             }
         } else {
-            taskView = savedInstanceState.getParcelable(ARGUMENT_TASK_VIEW);
+            taskIdentifier = savedInstanceState.getString(ARGUMENT_TASK_IDENTIFIER);
         }
-        checkState(taskView != null, "no taskView found");
+        checkState(!Strings.isNullOrEmpty(taskIdentifier), "taskIdentifier cannot be null or empty");
 
-        performTaskViewModel = ViewModelProviders.of(this, taskViewModelFactory.create(taskView))
+        performTaskViewModel = ViewModelProviders.of(this, taskViewModelFactory.create(taskIdentifier))
                 .get(PerformTaskViewModel.class);
 
         performTaskViewModel.getStep().observe(this, this::showStep);
@@ -143,7 +141,7 @@ public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
     @Override
     public void onSaveInstanceState(Bundle outState) {
         if (outState != null) {
-            outState.putParcelable(ARGUMENT_TASK_VIEW, taskView);
+            outState.putString(ARGUMENT_TASK_IDENTIFIER, taskIdentifier);
         }
     }
 

presentation/build.gradle

@@ -69,6 +69,8 @@ dependencies {
 
     implementation 'com.google.guava:guava:24.1-android'
     implementation "android.arch.lifecycle:extensions:1.1.1"
+    annotationProcessor "android.arch.lifecycle:compiler:1.1.1"
+
     implementation 'org.slf4j:slf4j-api:1.7.21'
 
     api 'com.google.dagger:dagger-android:2.15'
@@ -83,7 +85,11 @@ dependencies {
     annotationProcessor 'com.ryanharter.auto.value:auto-value-parcel:0.2.6'
 
     implementation 'com.android.support:appcompat-v7:27.1.1'
+
     testImplementation 'junit:junit:4.12'
+    testImplementation "android.arch.core:core-testing:1.1.1"
+    testImplementation 'org.mockito:mockito-core:2.8.9'
+
     androidTestImplementation 'com.android.support.test:runner:1.0.1'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
 }

presentation/src/main/java/org/sagebionetworks/research/presentation/mapper/TaskMapper.java

@@ -40,10 +40,17 @@
 import org.sagebionetworks.research.domain.task.Task;
 import org.sagebionetworks.research.presentation.model.TaskView;
 
+import javax.inject.Inject;
+
 /**
  * Map a {@link Task} to a {@link TaskView} when data is moving between the Domain layer and this layer.
  */
 public class TaskMapper implements Function<Task, TaskView> {
+    @Inject
+    public TaskMapper() {
+
+    }
+
     @Override
     @NonNull
     public TaskView apply(@NonNull Task input) {