Add base activity without a viewmodel. Add log in case view was not set.

Author: Daniel Novak

library/src/main/java/eu/inloop/viewmodel/AbstractViewModel.java

@@ -6,6 +6,7 @@
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v4.app.Fragment;
+import android.util.Log;
 
 public abstract class AbstractViewModel<T extends IView> {
 
@@ -15,6 +16,8 @@ public abstract class AbstractViewModel<T extends IView> {
     @Nullable
     private T mView;
 
+    private boolean mBindViewWasCalled;
+
     void setUniqueIdentifier(@NonNull final String uniqueIdentifier) {
         mUniqueIdentifier = uniqueIdentifier;
     }
@@ -44,6 +47,7 @@ public void onCreate(@Nullable Bundle arguments, @Nullable Bundle savedInstanceS
     }
 
     public void bindView(@NonNull T view) {
+        mBindViewWasCalled = true;
         mView = view;
     }
 
@@ -68,7 +72,9 @@ public void onStop() {
 
     @SuppressWarnings("EmptyMethod")
     public void onStart() {
-
+        if (mView == null && !mBindViewWasCalled) {
+            Log.e("AndroidViewModel", this.getClass().getSimpleName() + " - no view associated. You probably did not call setModelView() in your Fragment or Activity");
+        }
     }
 
     /**

library/src/main/java/eu/inloop/viewmodel/base/ViewModelBaseActivity.java

@@ -3,23 +3,17 @@
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
-import android.support.v7.app.AppCompatActivity;
 
 import eu.inloop.viewmodel.AbstractViewModel;
 import eu.inloop.viewmodel.IView;
-import eu.inloop.viewmodel.IViewModelProvider;
 import eu.inloop.viewmodel.ViewModelHelper;
-import eu.inloop.viewmodel.ViewModelProvider;
 
-public abstract class ViewModelBaseActivity<T extends IView, R extends AbstractViewModel<T>> extends AppCompatActivity implements IView, IViewModelProvider {
+public abstract class ViewModelBaseActivity<T extends IView, R extends AbstractViewModel<T>> extends ViewModelBaseEmptyActivity implements IView  {
 
     private final ViewModelHelper<T, R> mViewModeHelper = new ViewModelHelper<>();
-    private ViewModelProvider mViewModelProvider;
 
     @Override
     protected void onCreate(@Nullable final Bundle savedInstanceState) {
-        //This code must be execute prior to super.onCreate()
-        mViewModelProvider = ViewModelProvider.newInstance(this);
         super.onCreate(savedInstanceState);
         mViewModeHelper.onCreate(this, savedInstanceState, getViewModelClass(), getIntent().getExtras());
     }
@@ -35,12 +29,6 @@ public void setModelView(@NonNull final T view) {
 
     public abstract Class<R> getViewModelClass();
 
-    @Override
-    @Nullable
-    public Object onRetainCustomNonConfigurationInstance() {
-        return mViewModelProvider;
-    }
-
     @Override
     public void onSaveInstanceState(@NonNull final Bundle outState) {
         super.onSaveInstanceState(outState);
@@ -57,9 +45,6 @@ public void onStart() {
     public void onStop() {
         super.onStop();
         mViewModeHelper.onStop();
-        if (isFinishing()) {
-            mViewModelProvider.removeAllViewModels();
-        }
     }
 
     @Override
@@ -74,8 +59,4 @@ public R getViewModel() {
         return mViewModeHelper.getViewModel();
     }
 
-    @Override
-    public ViewModelProvider getViewModelProvider() {
-        return mViewModelProvider;
-    }
 }

library/src/main/java/eu/inloop/viewmodel/base/ViewModelBaseEmptyActivity.java

@@ -0,0 +1,44 @@
+package eu.inloop.viewmodel.base;
+
+import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.support.v7.app.AppCompatActivity;
+
+import eu.inloop.viewmodel.IViewModelProvider;
+import eu.inloop.viewmodel.ViewModelProvider;
+
+/**
+ * All your activities must extend this activity - even in case your activity has no viewmodel. The fragment viewmodels are using the {@link IViewModelProvider}
+ * interface to get the {@link ViewModelProvider} from the current activity.
+ * You can copy this implementation in case you don't want to extend this class.
+ */
+public abstract class ViewModelBaseEmptyActivity extends AppCompatActivity implements IViewModelProvider {
+
+    private ViewModelProvider mViewModelProvider;
+
+    @Override
+    protected void onCreate(@Nullable final Bundle savedInstanceState) {
+        //This code must be execute prior to super.onCreate()
+        mViewModelProvider = ViewModelProvider.newInstance(this);
+        super.onCreate(savedInstanceState);
+    }
+
+    @Override
+    @Nullable
+    public Object onRetainCustomNonConfigurationInstance() {
+        return mViewModelProvider;
+    }
+
+    @Override
+    public void onStop() {
+        super.onStop();
+        if (isFinishing()) {
+            mViewModelProvider.removeAllViewModels();
+        }
+    }
+
+    @Override
+    public ViewModelProvider getViewModelProvider() {
+        return mViewModelProvider;
+    }
+}

sample/src/main/java/eu/inloop/viewmodel/sample/activity/MainActivity.java

@@ -4,11 +4,12 @@
 
 import butterknife.ButterKnife;
 import eu.inloop.viewmodel.base.ViewModelBaseActivity;
+import eu.inloop.viewmodel.base.ViewModelBaseEmptyActivity;
 import eu.inloop.viewmodel.sample.R;
 import eu.inloop.viewmodel.sample.fragment.UserListFragment;
 
 
-public class MainActivity extends ViewModelBaseActivity {
+public class MainActivity extends ViewModelBaseEmptyActivity {
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -21,9 +22,4 @@ protected void onCreate(Bundle savedInstanceState) {
         }
     }
 
-    @Override
-    public Class getViewModelClass() {
-        return null;
-    }
-
 }

sample/src/main/java/eu/inloop/viewmodel/sample/activity/ViewPagerActivity.java

@@ -7,10 +7,11 @@
 import android.support.v4.view.ViewPager;
 
 import eu.inloop.viewmodel.base.ViewModelBaseActivity;
+import eu.inloop.viewmodel.base.ViewModelBaseEmptyActivity;
 import eu.inloop.viewmodel.sample.R;
 import eu.inloop.viewmodel.sample.fragment.PagerFragment;
 
-public class ViewPagerActivity extends ViewModelBaseActivity {
+public class ViewPagerActivity extends ViewModelBaseEmptyActivity {
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -21,11 +22,6 @@ protected void onCreate(Bundle savedInstanceState) {
         viewPager.setAdapter(new TestPagerAdapter(getSupportFragmentManager()));
     }
 
-    @Override
-    public Class getViewModelClass() {
-        return null;
-    }
-
     private final static class TestPagerAdapter extends FragmentStatePagerAdapter {
         public TestPagerAdapter(FragmentManager fm) {
             super(fm);