Include layout file into constraint layout without affecting performance or Android Studio previews

Question

I have a huge layout file with one flat constraint layout within.

I have android.support.constraint.Group elements that are identical. I want to move these to a separate file and then include them like <include layout="@layout/selection_group"/>

The problem I'm facing is that the group that I have in the file selection_group.xml is not previewed correctly in Android studio. Is there a way to make Android Studio preview this directly in the file or include them in a different way?

selection_group.xml

<layout 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.support.constraint.Group
        android:id="@+id/top_bar_config_one_background_group"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="@drawable/top_bar_background_with_border_fx"
        android:clickable="true"
        app:constraint_referenced_ids="top_bar_config_one,top_bar_tooth_one"
        app:layout_constraintBottom_toBottomOf="@+id/top_bar_container_background"
        app:layout_constraintLeft_toLeftOf="@+id/top_bar_container_background"
        app:layout_constraintRight_toLeftOf="@+id/top_bar_config_two"
        app:layout_constraintTop_toTopOf="@+id/top_bar_container_background" />

    <ImageView
        android:id="@+id/top_bar_config_one"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:clickable="false"
        android:scaleType="center"
        android:src="@drawable/ic_height_over_sea_100x26"
        app:layout_constraintBottom_toTopOf="@+id/top_bar_tooth_one"
        app:layout_constraintLeft_toLeftOf="@+id/top_bar_container_background"
        app:layout_constraintRight_toLeftOf="@+id/top_bar_config_two"
        app:layout_constraintTop_toTopOf="@+id/top_bar_config_one_background_group" />

    <ImageView
        android:id="@+id/top_bar_tooth_one"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleType="center"
        android:src="@drawable/ic_tooth_auto_40x40"
        app:layout_constraintBottom_toBottomOf="@+id/top_bar_config_one_background_group"
        app:layout_constraintLeft_toLeftOf="@+id/top_bar_container_background"
        app:layout_constraintRight_toLeftOf="@+id/top_bar_config_two" />
    <?xml version="1.0" encoding="utf-8"?>
</layout>

I don't want to nest multiple constraint layouts together. I think the root <layout> view in selection_group.xml is optimized and does not affect the performance? My goal is to reduce redundant code and not affect performance

Did you try to invalidate cache and restart android studio? You can check out this thread too. https://stackoverflow.com/questions/34499839/android-studio-does-not-show-layout-preview If this helps your cause. — Pronoy999, Jan 23 '20 at 09:22

score 1 · Accepted Answer · answered Jan 23 '20 at 14:01

1

Try added a merge tag to the included layout:

<layout>
    <merge>
    <group>
    ... etc. ...
    </merge>
</layout>

answered Jan 23 '20 at 14:01

Cheticamp

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Merge was exactly what I needed. Right-click refactor -> layout did this for me I figured. Didn't need the outer tags. – nilsi Jan 23 '20 at 14:24

score 1 · Answer 2 · answered Jan 23 '20 at 14:27

In order to make that layout file ready to be included you need to replace <layout> with <merge>

In case you need to use DataBinding into your layout you need to have <layout first and than <merge> tags on top of the layout file

I order to have proper preview in your inner layout which is going to be included - add on top level into merge tag:

tools:parentTag="ContraintLayout"

Something like this:

<merge 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"
tools:parentTag="androidx.constraintlayout.widget.ConstraintLayout">

Include layout file into constraint layout without affecting performance or Android Studio previews

2 Answers2