Hide the bottom navigation container if there are no visible buttons. (…

…google#2453)

* Hide bottomnavigation container if no buttons are visible.

* use constraintlayout to fix the issue.

* Change the constraints according to Submit button.

* Rmove redundant attributes.

---------

Co-authored-by: Santosh Pingle <spingle@google.com>

datacapture/src/main/res/layout/questionnaire_fragment.xml

@@ -72,13 +72,11 @@
         app:layout_constraintBottom_toTopOf="@id/bottom_nav_container"
     />
 
-    <LinearLayout
+    <androidx.constraintlayout.widget.ConstraintLayout
         android:id="@+id/bottom_nav_container"
         style="?attr/questionnaireBottomNavContainerStyle"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:layout_alignParentTop="true"
-        android:layout_alignParentBottom="true"
         android:orientation="horizontal"
         app:layout_constraintBottom_toBottomOf="parent"
     >
@@ -89,12 +87,9 @@
             android:layout_marginHorizontal="@dimen/action_button_margin_horizontal"
             android:layout_marginVertical="@dimen/action_button_margin_vertical"
             android:text="@string/cancel_questionnaire"
-        />
-
-        <View
-            android:layout_width="0dp"
-            android:layout_height="match_parent"
-            android:layout_weight="1"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintBottom_toBottomOf="parent"
         />
 
         <Button
@@ -103,6 +98,9 @@
             android:layout_marginHorizontal="@dimen/action_button_margin_horizontal"
             android:layout_marginVertical="@dimen/action_button_margin_vertical"
             android:text="@string/button_pagination_previous"
+            app:layout_constraintEnd_toStartOf="@+id/pagination_next_button"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintBottom_toBottomOf="parent"
         />
 
         <Button
@@ -111,6 +109,9 @@
             android:layout_marginHorizontal="@dimen/action_button_margin_horizontal"
             android:layout_marginVertical="@dimen/action_button_margin_vertical"
             android:text="@string/button_pagination_next"
+            app:layout_constraintEnd_toStartOf="@+id/submit_questionnaire"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintBottom_toBottomOf="parent"
         />
 
         <Button
@@ -119,16 +120,24 @@
             android:layout_marginHorizontal="@dimen/action_button_margin_horizontal"
             android:layout_marginVertical="@dimen/action_button_margin_vertical"
             android:text="@string/button_review"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintBottom_toBottomOf="parent"
         />
 
         <Button
             android:id="@+id/submit_questionnaire"
             style="?attr/questionnaireSubmitButtonStyle"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
             android:layout_marginHorizontal="@dimen/action_button_margin_horizontal"
             android:layout_marginVertical="@dimen/action_button_margin_vertical"
             android:text="@string/submit_questionnaire"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintBottom_toBottomOf="parent"
         />
 
-    </LinearLayout>
+    </androidx.constraintlayout.widget.ConstraintLayout>
 
 </androidx.constraintlayout.widget.ConstraintLayout>

datacapture/src/main/res/values/dimens.xml

@@ -23,7 +23,7 @@
 
     <!--  Action button  -->
     <dimen name="action_button_margin_horizontal">16dp</dimen>
-    <dimen name="action_button_margin_vertical">8dp</dimen>
+    <dimen name="action_button_margin_vertical">16dp</dimen>
 
     <!--  Header  -->
     <dimen name="error_text_at_header_margin_top">4dp</dimen>

datacapture/src/main/res/values/styles.xml

@@ -227,12 +227,6 @@
 
     <style name="Questionnaire.BottomNavContainerStyle" parent="">
       <item name="android:background">?attr/colorSurface</item>
-      <item
-            name="android:paddingTop"
-        >@dimen/bottom_container_padding_vertical</item>
-      <item
-            name="android:paddingBottom"
-        >@dimen/bottom_container_padding_vertical</item>
     </style>
 
     <style