Add swap button to route form

app/src/main/java/com/dougkeen/bart/activities/AbstractRouteSelectionFragment.java

@@ -14,6 +14,8 @@ import android.support.v7.app.AlertDialog;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.widget.ArrayAdapter;
+import android.widget.Button;
+import android.widget.ImageButton;
 import android.widget.Spinner;
 import android.widget.Toast;
 
@@ -80,6 +82,16 @@ public abstract class AbstractRouteSelectionFragment extends DialogFragment {
                 .findViewById(R.id.destination_spinner);
         destinationSpinner.setAdapter(destinationSpinnerAdapter);
         destinationSpinner.setSelection(lastSelectedDestinationPosition);
+
+        final ImageButton swapButton = (ImageButton) dialog.findViewById(R.id.swap_button);
+        swapButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                int destinationSelection = destinationSpinner.getSelectedItemPosition();
+                destinationSpinner.setSelection(originSpinner.getSelectedItemPosition());
+                originSpinner.setSelection(destinationSelection);
+            }
+        });
     }
 
     @NonNull

app/src/main/res/layout/route_form.xml

@@ -38,16 +38,25 @@
         android:text="@string/origin"
         android:textSize="15sp"></TextView>
 
+    <ImageButton
+        android:id="@+id/swap_button"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:src="@drawable/ic_action_action_swap_vert"
+        style="?android:attr/borderlessButtonStyle"
+        android:layout_alignLeft="@id/origin_spinner"
+        android:layout_below="@id/origin_spinner"
+        />
+
     <Spinner
         android:id="@+id/destination_spinner"
         android:layout_width="200dp"
         android:layout_height="wrap_content"
         android:layout_alignParentRight="true"
-        android:layout_below="@+id/origin_spinner"
+        android:layout_below="@+id/swap_button"
         android:drawSelectorOnTop="true"
         android:paddingLeft="5dp"
         android:paddingRight="5dp"
-        android:paddingTop="15dip"
         />
 
     <TextView
@@ -56,11 +65,10 @@
         android:layout_height="wrap_content"
         android:layout_alignBottom="@+id/destination_spinner"
         android:layout_alignParentLeft="true"
-        android:layout_below="@+id/origin_spinner"
+        android:layout_below="@+id/swap_button"
         android:gravity="center_vertical"
         android:paddingLeft="5dp"
         android:paddingRight="5dp"
-        android:paddingTop="15dip"
         android:text="@string/destination"
         android:textSize="15sp"></TextView>