Permanent implementation of the OG holder pattern

app/src/main/java/org/bspeice/minimalbible/OGHolder.java

@@ -0,0 +1,50 @@
+package org.bspeice.minimalbible;
+
+import android.content.Context;
+import android.os.Bundle;
+import android.support.v4.app.Fragment;
+import android.support.v4.app.FragmentActivity;
+import android.support.v4.app.FragmentManager;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import dagger.ObjectGraph;
+
+/**
+ * Holding location for activity object graphs.
+ * This technique could be extended to other things, but honestly,
+ * everything it could be extended to likely needs to be in
+ * an ObjectGraph anyway.
+ * This works because getSupportFragmentManager() is scoped to each activity.
+ * TODO: Prove the above claim.
+ */
+public class OGHolder extends Fragment {
+    private final static String TAG = "OGHolder";
+
+    private ObjectGraph mObjectGraph;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setRetainInstance(true);
+    }
+
+    public void persistGraph(ObjectGraph graph) {
+        mObjectGraph = graph;
+    }
+
+    public ObjectGraph fetchGraph() {
+        return mObjectGraph;
+    }
+
+    public static OGHolder get(FragmentActivity activity) {
+        FragmentManager manager = activity.getSupportFragmentManager();
+        OGHolder holder = (OGHolder) manager.findFragmentByTag(TAG);
+        if (holder == null) {
+            holder = new OGHolder();
+            manager.beginTransaction().add(holder, TAG).commit();
+        }
+        return holder;
+    }
+}

app/src/main/java/org/bspeice/minimalbible/activity/downloader/DownloadActivity.java

@@ -10,6 +10,7 @@ import android.view.MenuItem;
 
 import org.bspeice.minimalbible.Injector;
 import org.bspeice.minimalbible.MinimalBible;
+import org.bspeice.minimalbible.OGHolder;
 import org.bspeice.minimalbible.R;
 import org.bspeice.minimalbible.activity.BaseActivity;
 import org.bspeice.minimalbible.activity.BaseNavigationDrawerFragment;
@@ -26,6 +27,8 @@ public class DownloadActivity extends BaseActivity implements
 		BaseNavigationDrawerFragment.NavigationDrawerCallbacks,
         Injector {
 
+    private final String TAG = "DownloadActivity";
+
 	/**
 	 * Fragment managing the behaviors, interactions and presentation of the
 	 * navigation drawer.
@@ -48,19 +51,15 @@ public class DownloadActivity extends BaseActivity implements
      */
     private void buildObjGraph() {
         if (daObjectGraph == null) {
-            FragmentManager fM = getSupportFragmentManager();
+            OGHolder holder = OGHolder.get(this);
-            DownloadOGHolder ogHolder = (DownloadOGHolder) fM.findFragmentByTag("OG_HOLDER");
+            ObjectGraph holderGraph = holder.fetchGraph();
-            if (ogHolder == null) {
+            if (holderGraph == null) {
-                Log.e("DownloadActivity", "Creating new holder...");
+                Log.i(TAG, "Rebuilding ObjectGraph...");
-                ogHolder = new DownloadOGHolder();
                 daObjectGraph = MinimalBible.get(this)
                         .plus(new DownloadActivityModules(this));
-                ogHolder.persistObjectGraph(daObjectGraph);
+                holder.persistGraph(daObjectGraph);
-                fM.beginTransaction().add(ogHolder, "OG_HOLDER").commit();
             } else {
-                Log.e("DownloadActivity", "Found existing holder...");
+                daObjectGraph = holderGraph;
-                daObjectGraph = ogHolder.fetchObjectGraph();
-                daObjectGraph.inject(this);
             }
         }
         daObjectGraph.inject(this);

app/src/main/java/org/bspeice/minimalbible/activity/downloader/DownloadOGHolder.java

@@ -1,28 +0,0 @@
-package org.bspeice.minimalbible.activity.downloader;
-
-import android.os.Bundle;
-import android.support.v4.app.Fragment;
-
-import dagger.ObjectGraph;
-
-/**
- * Created by bspeice on 7/21/14.
- */
-public class DownloadOGHolder extends Fragment {
-
-    ObjectGraph holder;
-
-    @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-        setRetainInstance(true);
-    }
-
-    public void persistObjectGraph(ObjectGraph holder) {
-        this.holder = holder;
-    }
-
-    public ObjectGraph fetchObjectGraph() {
-        return this.holder;
-    }
-}