android Studio layout preview is empty when include layout into the coordinatior view

Question

After I have posted this question, it wasnt giving enough detail, now I have come to a point where the problem occurs. so I have edited my question to a specific way below

EDITED

Hi , I have tried many possible solutions but preview layout not giving rendering error.

It gives the error on coordinatorLayout. It shows preview actually for coordinator layout but it shows nothing when I include another layout using

<include layout="@layout/content_main" />

into the coordinatorview

I have tried to clean and build project, I have tried to change the app style to the one below

<style name="AppTheme" parent="Base.Theme.AppCompat.Light.DarkActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>

I have changed the preview api from 22 to others

But nothing works.

while it does preview the other layouts, it doesnt do it in both included layout and the coordinatorlayout. when I comment the include tag line, then it displays what is in it.

SO WHAT AM I DOING WITH THIS COORDINATORVIEW AND INCLUDED LAYOUT??

I dont know!! I have android studio 1.5.1 and I have JUST create an BLANK ACTIVITY ınstead of empty activity, then it automatically creates these layouts. no idea why

here are the screenshots of both layouts.

here are the codes content layout

<?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="com.example.algtek.magnetotest.MainActivity"
tools:showIn="@layout/activity_main">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!" />
</RelativeLayout>

coordinator layout

<?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.example.algtek.magnetotest.MainActivity">

<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/content_main" />

<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="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>

Answer 1

I had the same bug in Android Studio 2.1.1 and managed to resolve it by tweaking the content of the include_view.

I don't know why but the empty preview comes from the attribute:

app:layout_behavior="@string/appbar_scrolling_view_behavior"

The trick is to have this attribute in the main layout and have an included layout for the content. This way everything works as expected...

Here is what you should have.

Activity layout :

<?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.example.algtek.magnetotest.MainActivity">

<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>

<android.support.v4.widget.NestedScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <include layout="@layout/content_main" />

</android.support.v4.widget.NestedScrollView>

<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="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>

content_main.xml :

<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">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!" />
</RelativeLayout>

Do not forget to remove the tools:showIn in your included xml. It seems that it keeps the preview broken (probably because it tries to render the app:layout_behavior).

I took the liberty of adding a NestedScrollView as a parent of the RelativeLayout so that you can take advantage of the CoordinatorLayout. If you don't want/need the NestedScrollView, replace it by your RelativeLayout and use a merge tag as the parent of your main_content.xml

Answer 2

Activity layout XML looks OK. Problem could be in the included content_main layout. Open that and see if it renders fine first. Also post the XML for that layout here. Does it have any views added to it? They should show. If not, try adding some and then check if the rendering works for the activity layout then.