"Up" navigation now brings you back to the selected label

app/src/main/java/ch/dissem/apps/abit/DetailActivity.java

@@ -35,8 +35,8 @@ public abstract class DetailActivity extends AppCompatActivity {
 
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
-        int id = item.getItemId();
+        switch (item.getItemId()) {
-        if (id == android.R.id.home) {
+            case android.R.id.home:
                 // This ID represents the Home or Up button. In the case of this
                 // activity, the Up button is shown. Use NavUtils to allow users
                 // to navigate up one level in the application structure. For
@@ -46,7 +46,8 @@ public abstract class DetailActivity extends AppCompatActivity {
                 //
                 NavUtils.navigateUpTo(this, new Intent(this, MainActivity.class));
                 return true;
-        }
+            default:
                 return super.onOptionsItemSelected(item);
         }
     }
+}

app/src/main/java/ch/dissem/apps/abit/MainActivity.java

@@ -91,6 +91,7 @@ import static ch.dissem.apps.abit.service.BitmessageService.isRunning;
 public class MainActivity extends AppCompatActivity
     implements ListSelectionListener<Serializable>, ActionBarListener {
     public static final String EXTRA_SHOW_MESSAGE = "ch.dissem.abit.ShowMessage";
+    public static final String EXTRA_SHOW_LABEL = "ch.dissem.abit.ShowLabel";
     public static final String EXTRA_REPLY_TO_MESSAGE = "ch.dissem.abit.ReplyToMessage";
     public static final String ACTION_SHOW_INBOX = "ch.dissem.abit.ShowInbox";
 
@@ -122,7 +123,9 @@ public class MainActivity extends AppCompatActivity
         instance = new WeakReference<>(this);
         bmc = Singleton.getBitmessageContext(this);
         List<Label> labels = bmc.messages().getLabels();
-        if (selectedLabel == null) {
+        if (getIntent().hasExtra(EXTRA_SHOW_LABEL)) {
+            selectedLabel = (Label) getIntent().getSerializableExtra(EXTRA_SHOW_LABEL);
+        } else if (selectedLabel == null) {
             selectedLabel = labels.get(0);
         }
 
@@ -508,15 +511,16 @@ public class MainActivity extends AppCompatActivity
             // In single-pane mode, simply start the detail activity
             // for the selected item ID.
             Intent detailIntent;
-            if (item instanceof Plaintext)
+            if (item instanceof Plaintext) {
                 detailIntent = new Intent(this, MessageDetailActivity.class);
-            else if (item instanceof BitmessageAddress)
+                detailIntent.putExtra(EXTRA_SHOW_LABEL, selectedLabel);
+            } else if (item instanceof BitmessageAddress) {
                 detailIntent = new Intent(this, AddressDetailActivity.class);
-            else
+            } else {
                 throw new IllegalArgumentException("Plaintext or BitmessageAddress expected, but " +
                     "was "
                     + item.getClass().getSimpleName());
-
+            }
             detailIntent.putExtra(MessageDetailFragment.ARG_ITEM, item);
             startActivity(detailIntent);
         }

app/src/main/java/ch/dissem/apps/abit/MessageDetailActivity.java

@@ -1,6 +1,11 @@
 package ch.dissem.apps.abit;
 
+import android.content.Intent;
 import android.os.Bundle;
+import android.support.v4.app.NavUtils;
+import android.view.MenuItem;
+
+import ch.dissem.bitmessage.entity.valueobject.Label;
 
 
 /**
@@ -13,6 +18,7 @@ import android.os.Bundle;
  * more than a {@link MessageDetailFragment}.
  */
 public class MessageDetailActivity extends DetailActivity {
+    private Label label;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -28,6 +34,7 @@ public class MessageDetailActivity extends DetailActivity {
         // http://developer.android.com/guide/components/fragments.html
         //
         if (savedInstanceState == null) {
+            label = (Label) getIntent().getSerializableExtra(MainActivity.EXTRA_SHOW_LABEL);
             // Create the detail fragment and add it to the activity
             // using a fragment transaction.
             Bundle arguments = new Bundle();
@@ -40,4 +47,17 @@ public class MessageDetailActivity extends DetailActivity {
                 .commit();
         }
     }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        switch (item.getItemId()) {
+            case android.R.id.home:
+                Intent parentIntent = new Intent(this, MainActivity.class);
+                parentIntent.putExtra(MainActivity.EXTRA_SHOW_LABEL, label);
+                NavUtils.navigateUpTo(this, parentIntent);
+                return true;
+            default:
+                return super.onOptionsItemSelected(item);
+        }
+    }
 }