fix #864, fixing a glitch at 1 tab visible only

Author: tibbi

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

@@ -21,7 +21,7 @@
 
     </com.google.android.material.appbar.AppBarLayout>
 
-    <RelativeLayout
+    <androidx.constraintlayout.widget.ConstraintLayout
         android:id="@+id/main_holder"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
@@ -30,30 +30,32 @@
         <com.simplemobiletools.commons.views.MyViewPager
             android:id="@+id/view_pager"
             android:layout_width="match_parent"
-            android:layout_height="match_parent"
-            android:layout_above="@+id/main_tabs_holder" />
+            android:layout_height="0dp"
+            app:layout_constraintBottom_toTopOf="@+id/main_tabs_holder"
+            app:layout_constraintTop_toTopOf="parent" />
 
         <ImageView
             android:id="@+id/main_dialpad_button"
             android:layout_width="@dimen/dialpad_button_size"
             android:layout_height="@dimen/dialpad_button_size"
-            android:layout_above="@+id/main_tabs_holder"
-            android:layout_centerHorizontal="true"
             android:layout_marginBottom="@dimen/activity_margin"
             android:background="@drawable/circle_background"
             android:contentDescription="@string/dialpad"
             android:elevation="@dimen/medium_margin"
             android:padding="@dimen/activity_margin"
-            android:src="@drawable/ic_dialpad_vector" />
+            android:src="@drawable/ic_dialpad_vector"
+            app:layout_constraintBottom_toTopOf="@+id/main_tabs_holder"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent" />
 
         <com.google.android.material.tabs.TabLayout
             android:id="@+id/main_tabs_holder"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
-            android:layout_alignParentBottom="true"
+            app:layout_constraintBottom_toBottomOf="parent"
             app:tabIndicator="@null"
             app:tabMinWidth="150dp"
             app:tabRippleColor="@null" />
 
-    </RelativeLayout>
+    </androidx.constraintlayout.widget.ConstraintLayout>
 </androidx.coordinatorlayout.widget.CoordinatorLayout>

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

@@ -1,10 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
-<com.simplemobiletools.contacts.pro.fragments.ContactsFragment
-    xmlns:android="http://schemas.android.com/apk/res/android"
+<com.simplemobiletools.contacts.pro.fragments.ContactsFragment xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/contacts_fragment"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
-    <include layout="@layout/fragment_letters_layout"/>
+    <include layout="@layout/fragment_letters_layout" />
 
 </com.simplemobiletools.contacts.pro.fragments.ContactsFragment>