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Android Studio does not show layout preview(no error occurs also)

Android Studio does not display a preview of the layout. No errors or warnings are showing. I already try this solution Invalidate Caches/ Restart.
XML File :
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context=".MainActivity">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:showIn="#layout/activity_main"
tools:context=".MainActivity">
<ListView
android:id="#+id/peripherals_list"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<TextView android:id="#+id/peripheral_list_empty"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="#string/peripheral_list_empty"/>
</RelativeLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="#+id/txt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World!"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ListView
android:id="#+id/list"
android:layout_width="wrap_content"
android:layout_below="#+id/txt"
android:layout_height="wrap_content"/>
</RelativeLayout>

If the system UI is on Listview will not show. Look for an icon with eye and unmark show system UI

where can I add include in my xml file?

I'm trying to add a toolbar in my xml files.
So I made toolbar.xml and I need to include it in upload.xml:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_upload"
android:layout_width="match_parent"
android:padding="10dp"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.sk.mf.Upload"
android:background="#fff">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/imageToUpload"
android:layout_gravity="center_horizontal"
android:layout_width="150dp"
android:layout_height="150dp" />
<EditText
android:id="#+id/etUploadName"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<Button
android:id="#+id/bUploadImage"
android:text="Upload Image"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</ScrollView>
the problem is, anywhere I place it I had error like:
scrollview can host only one direct child (inside scrollview)
multiple root tags (after scrollview)
...
my question here is, where and how can I put the code below in the xml above?
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include android:id="#+id/toolbar" layout="#layout/toolbar"></include>
</RelativeLayout>

try this : wrap your layout in LinearLayout and the toolbar tag
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include
android:id="#+id/toolbar"
layout="#layout/toolbar"></include>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_upload"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#fff"
android:padding="10dp"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.sk.mf.Upload">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<ImageView
android:id="#+id/imageToUpload"
android:layout_width="150dp"
android:layout_height="150dp"
android:layout_gravity="center_horizontal" />
<EditText
android:id="#+id/etUploadName"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<Button
android:id="#+id/bUploadImage"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Upload Image" />
</LinearLayout>
</ScrollView>
</LinearLayout>

Why my toolbar is overlapping my textView?

This is the xml layout of the file
Here, when i made the layout the toolbar is overlapping the content of my textView, Why this is happening.
Have tried several other things but no luck..!!!
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/drawer"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.alpit.formula2.MainActivity">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:weightSum="1">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="alpit isfdfsdfwefwes great jhfjhvjhhbnmbjk"
android:textSize="20dp" />
</RelativeLayout>
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="start"
app:menu="#menu/navigation_menu"
>
</android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>
This is my current situation.

add top margin to relativelayout like
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:weightSum="1">
I should have written this as comment but I don't have reputations so I have added it as answer

try this give margin to Textview
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/drawer"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.alpit.formula2.MainActivity">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text=" alpit isfdfsdfwefwes great jhfjhvjhhbnmbjk"
android:textSize="20dp" />
</RelativeLayout>
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="start"
app:menu="#menu/navigation_menu"
></android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>

Don't put hard coded values to layout you can try this,
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="#dimen/activity_vertical_margin"
android:text="alpit isfdfsdfwefwes great jhfjhvjhhbnmbjk"
android:textSize="?android:textAppearanceMedium" />
</RelativeLayout>

remove
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
and use into relative_layout
android:layout_marginTop="#dimen/activity_vertical_margin"

Problem is just because you have given padding to your Drawer layout and your relative layout start drawing from top which includes paddingTop also
please try below code
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/drawer"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:weightSum="1"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="alpit isfdfsdfwefwes great jhfjhvjhhbnmbjk"
android:textSize="20dp" />
</RelativeLayout>
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="start"
app:menu="#menu/navigation_menu"
>
</android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>
also you can use parent layout as relative layout and inside these use Drawer layout

Enable textView above fragment

How can i be able to enable this textView on top of the fragment. I want it to remain static even when fragments change from one another. Iam having no luck enabling it on top. Here is my layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.skwebviewapp.MainActivity">
<fragment
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:id="#+id/mainFragment"
tools:layout="#layout/fragment_main" />
<TextView
android:layout_width="wrap_content"
android:layout_height="16dp"
android:id="#+id/textView"
android:text="#string/app_name"/>
</LinearLayout>

Try below code,
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.skwebviewapp.MainActivity”
android:orientation=“vertical"
android:weightSum=“1.0">
<TextView
android:layout_width="wrap_content"
android:layout_height=“0dp”
android:layout_weight=“0.10"
android:id="#+id/textView"
android:text="#string/app_name”/>
<fragment
android:layout_width="match_parent"
android:layout_height=“0dp"
android:layout_weight=“0.90"
android:id="#+id/mainFragment"
tools:layout="#layout/fragment_main" />
</LinearLayout>

You can try this with RelativeLayout.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="#+id/textView"
android:layout_width="match_parent"
android:layout_height="16dp"
android:text="#string/app_name" />
<fragment xmlns:map="http://schemas.android.com/apk/res-auto"
android:id="#+id/map_view_fargment"
android:name="com.google.android.gms.maps.MapFragment"
class="com.google.android.gms.maps.MapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="40dp"
/>
</LinearLayout>

Layout overlapping included layout

I have a layout A that includes another layout B, but A overlaps B such that part of B isn't shown.
This is layout B:
and this is the source code:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:id="#+id/listView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true" />
</RelativeLayout>
and layout A:
and its source:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.byte64.i_assembly.activity.BillDetailActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<include layout="#layout/test_layout" />
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="#dimen/fab_margin"
android:src="#drawable/ic_action_download" />
</android.support.design.widget.CoordinatorLayout>
as you can see the first item in the list is hidden.How do i solve this? I've played around with the layout_height and layout_width of both layouts with no luck.

Use your test_layout like this.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context=".MainActivity"
tools:showIn="#layout/activity_main">
<ListView
android:id="#+id/listView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true" />
</RelativeLayout>
Change value of tools:context=".MainActivity" with your layout where you want to display.
Change your name of layout in tools:showIn="#layout/activity_main" if you are not using default name of layou

you should add xmlns:app="http://schemas.android.com/apk/res-auto" and app:layout_behavior="#string/appbar_scrolling_view_behavior"to your RelativeLayout which wrapp ListView , this work for me

Try this out...
<android.support.v4.widget.NestedScrollView
android:id="#+id/scrollView"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- include your layout-->
</android.support.v4.widget.NestedScrollView>