[android] Constraint Layout Vertical Align Center

How to vertically align and center objects in constraint layout? It is possible to align vertically or horizontally but I have not found a way to center at the same time beside constraining the views between two gridlines.

Vertical Align Center: enter image description here

It seems like centering is a huge problem with constraint layout which forces me to go back to relative layout for "centerInParent", "centerVertical", and "centerHorizontal".

I would like to create the layout boxed in red using constraint layout: enter image description here

Unfortunately, the only way I found without using two gridlines is with nested Relative and LinearLayouts (which Constraint Layout was supposed to solve this exact scenario!).

Layout using Relative and Linear Layout:

<RelativeLayout
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginTop="12dp"
    app:layout_constraintTop_toBottomOf="@id/user_points"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent">

    <LinearLayout
        android:id="@+id/stat_1_layout"
        android:layout_width="60dp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="12dp"
        android:layout_marginRight="12dp"
        android:layout_centerVertical="true"
        android:layout_toLeftOf="@+id/divider_1"
        android:orientation="vertical">

        <TextView
            android:id="@+id/stat_1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:gravity="center_horizontal"
            android:text="10"
            android:textSize="16dp"
            android:textColor="@color/textSecondaryDark"
            android:maxLines="1"/>

        <TextView
            android:id="@+id/stat_detail_1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:gravity="center"
            android:text="Streak"
            android:textSize="8sp"
            android:textColor="@color/textSecondary"
            android:maxLines="1"/>
    </LinearLayout>

    <View
        android:id="@+id/divider_1"
        android:layout_width="1dp"
        android:layout_height="38dp"
        android:layout_toLeftOf="@+id/stat_2_layout"
        android:background="@drawable/linedivider"/>

    <LinearLayout
        android:id="@+id/stat_2_layout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="18dp"
        android:layout_marginRight="18dp"
        android:layout_centerInParent="true"
        android:orientation="vertical">

        <TextView
            android:id="@+id/stat_2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:gravity="center_horizontal"
            android:text="243"
            android:textSize="16dp"
            android:textColor="@color/textSecondaryDark"
            android:maxLines="1"/>

        <TextView
            android:id="@+id/stat_detail_2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:gravity="center"
            android:text="Calories Burned"
            android:textSize="8sp"
            android:textColor="@color/textSecondary"
            android:maxLines="1"/>
    </LinearLayout>

    <View
        android:id="@+id/divider_2"
        android:layout_width="1dp"
        android:layout_height="38dp"
        android:layout_toRightOf="@+id/stat_2_layout"
        android:background="@drawable/linedivider"/>

    <LinearLayout
        android:id="@+id/stat_3_layout"
        android:layout_width="60dp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="12dp"
        android:layout_marginRight="12dp"
        android:layout_toRightOf="@+id/divider_2"
        android:layout_centerVertical="true"
        android:orientation="vertical">

        <TextView
            android:id="@+id/stat_3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:gravity="center_horizontal"
            android:text="3200"
            android:textSize="16dp"
            android:textColor="@color/textSecondaryDark"
            android:maxLines="1"/>

        <TextView
            android:id="@+id/stat_detail_3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:gravity="center"
            android:text="Steps"
            android:textSize="8sp"
            android:textColor="@color/textSecondary"
            android:maxLines="1"/>
    </LinearLayout>
</RelativeLayout>

The answer is


I also had a requirement something similar to it. I wanted to have a container in the center of the screen and inside the container there are many views. Following is the xml layout code. Here i'm using nested constraint layout to create container in the center of the screen.

    <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:background="@drawable/gradient_background"
tools:context=".activities.AppInfoActivity">

<ImageView
    android:id="@+id/ivClose"
    android:layout_width="30dp"
    android:layout_height="30dp"
    android:layout_marginStart="20dp"
    android:layout_marginTop="20dp"
    android:src="@drawable/ic_round_close_24"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<androidx.constraintlayout.widget.ConstraintLayout
    android:layout_width="300dp"
    android:layout_height="300dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.5">

    <ImageView
        android:id="@+id/ivAppIcon"
        android:layout_width="100dp"
        android:layout_height="100dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/dead" />

    <TextView
        android:id="@+id/tvAppName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Birds Shooter Plane"
        android:textAlignment="center"
        android:textSize="30sp"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/ivAppIcon" />

    <TextView
        android:id="@+id/tvAppVersion"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Version : 1.0"
        android:textAlignment="center"
        android:textSize="12sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvAppName" />

    <TextView
        android:id="@+id/tvDevelopedBy"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="25dp"
        android:text="Developed by"
        android:textAlignment="center"
        android:textSize="12sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvAppVersion" />

    <TextView
        android:id="@+id/tvDevelopedName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:text="K Pradeep Kumar Reddy"
        android:textAlignment="center"
        android:textSize="14sp"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvDevelopedBy" />

    <TextView
        android:id="@+id/tvContact"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:text="Contact : [email protected]"
        android:textAlignment="center"
        android:textSize="12sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvDevelopedName" />

    <TextView
        android:id="@+id/tvCheckForUpdate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="25dp"
        android:text="@string/check_for_update"
        android:textAlignment="center"
        android:textSize="14sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvContact" />
</androidx.constraintlayout.widget.ConstraintLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

Here is the screenshot of the layout enter image description here

Other solution is to remove the nested constraint layout and add constraint_vertical_bias = 0.5 attribute to the top element in the center of layout. I think this is called as chaining of views.

<?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:background="@drawable/gradient_background"
tools:context=".activities.AppInfoActivity">

<ImageView
android:id="@+id/ivClose"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:src="@drawable/ic_round_close_24"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />

<ImageView
android:id="@+id/ivAppIcon"
android:layout_width="100dp"
android:layout_height="100dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.5"
app:srcCompat="@drawable/dead" />

<TextView
android:id="@+id/tvAppName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/app_display_name"
android:textAlignment="center"
android:textSize="30sp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/ivAppIcon" />

<TextView
android:id="@+id/tvAppVersion"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/version"
android:textAlignment="center"
android:textSize="12sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tvAppName" />

<TextView
android:id="@+id/tvDevelopedBy"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="25dp"
android:text="@string/developed_by"
android:textAlignment="center"
android:textSize="12sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tvAppVersion" />

<TextView
android:id="@+id/tvDevelopedName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:text="@string/developer_name"
android:textAlignment="center"
android:textSize="14sp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tvDevelopedBy" />

<TextView
android:id="@+id/tvContact"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:text="@string/developer_email"
android:textAlignment="center"
android:textSize="12sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tvDevelopedName" />
<TextView
android:id="@+id/tvCheckForUpdate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="25dp"
android:text="@string/check_for_update"
android:textAlignment="center"
android:textSize="14sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tvContact" />
</androidx.constraintlayout.widget.ConstraintLayout>

Here is the screenshot of the layout enter image description here


 <TextView
        android:id="@+id/tvName"
        style="@style/textViewBoldLarge"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="Welcome"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>

You can easily center multiple things by creating a chain. It works both vertically and horizontally

Link to official documentation about chains

Edit to answer comment :

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
    <TextView
        android:id="@+id/first_score"
        android:layout_width="60dp"
        android:layout_height="wrap_content"
        android:text="10"
        app:layout_constraintEnd_toStartOf="@+id/second_score"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@+id/second_score"
        app:layout_constraintBottom_toTopOf="@+id/subtitle"
        app:layout_constraintHorizontal_chainStyle="spread"
        app:layout_constraintVertical_chainStyle="packed"
        android:gravity="center"
        />
    <TextView
        android:id="@+id/subtitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Subtitle"
        app:layout_constraintTop_toBottomOf="@+id/first_score"
        app:layout_constraintBottom_toBottomOf="@+id/second_score"
        app:layout_constraintStart_toStartOf="@id/first_score"
        app:layout_constraintEnd_toEndOf="@id/first_score"
        />
    <TextView
        android:id="@+id/second_score"
        android:layout_width="60dp"
        android:layout_height="120sp"
        android:text="243"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/thrid_score"
        app:layout_constraintStart_toEndOf="@id/first_score"
        app:layout_constraintTop_toTopOf="parent"
        android:gravity="center"
        />
    <TextView
        android:id="@+id/thrid_score"
        android:layout_width="60dp"
        android:layout_height="wrap_content"
        android:text="3200"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@id/second_score"
        app:layout_constraintTop_toTopOf="@id/second_score"
        app:layout_constraintBottom_toBottomOf="@id/second_score"
        android:gravity="center"
        />
</android.support.constraint.ConstraintLayout>

This code gives this result

You have the horizontal chain : first_score <=> second_score <=> third_score. second_score is centered vertically. The other scores are centered vertically according to it.

You can definitely create a vertical chain first_score <=> subtitle and center it according to second_score


May be i did not fully understand the problem, but, centering all view inside a ConstraintLayout seems very simple. This is what I used:

<android.support.constraint.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="wrap_content"
android:layout_gravity="center">

enter image description here

Last two lines did the trick!


If you have a ConstraintLayout with some size, and a child View with some smaller size, you can achieve centering by constraining the child's two edges to the same two edges of the parent. That is, you can write:

app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"

or

app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"

Because the view is smaller, these constraints are impossible. But ConstraintLayout will do the best it can, and each constraint will "pull" at the child view equally, thereby centering it.

This concept works with any target view, not just the parent.

Update

Below is XML that achieves your desired UI with no nesting of views and no Guidelines (though guidelines are not inherently evil).

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#eee">

    <TextView
        android:id="@+id/title1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginBottom="12dp"
        android:gravity="center"
        android:textColor="#777"
        android:textSize="22sp"
        android:text="10"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/divider1"
        app:layout_constraintBottom_toBottomOf="parent"/>

    <TextView
        android:id="@+id/label1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:textColor="#777"
        android:textSize="12sp"
        android:text="Streak"
        app:layout_constraintTop_toBottomOf="@+id/title1"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/divider1"/>

    <View
        android:id="@+id/divider1"
        android:layout_width="1dp"
        android:layout_height="55dp"
        android:layout_marginTop="12dp"
        android:layout_marginBottom="12dp"
        android:background="#ccc"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toRightOf="@+id/title1"
        app:layout_constraintRight_toLeftOf="@+id/title2"
        app:layout_constraintBottom_toBottomOf="parent"/>

    <TextView
        android:id="@+id/title2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginBottom="12dp"
        android:gravity="center"
        android:textColor="#777"
        android:textSize="22sp"
        android:text="243"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toRightOf="@+id/divider1"
        app:layout_constraintRight_toLeftOf="@+id/divider2"
        app:layout_constraintBottom_toBottomOf="parent"/>

    <TextView
        android:id="@+id/label2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:textColor="#777"
        android:textSize="12sp"
        android:text="Calories Burned"
        app:layout_constraintTop_toBottomOf="@+id/title2"
        app:layout_constraintLeft_toRightOf="@+id/divider1"
        app:layout_constraintRight_toLeftOf="@+id/divider2"/>

    <View
        android:id="@+id/divider2"
        android:layout_width="1dp"
        android:layout_height="55dp"
        android:layout_marginTop="12dp"
        android:layout_marginBottom="12dp"
        android:background="#ccc"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toRightOf="@+id/title2"
        app:layout_constraintRight_toLeftOf="@+id/title3"
        app:layout_constraintBottom_toBottomOf="parent"/>

    <TextView
        android:id="@+id/title3"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginBottom="12dp"
        android:gravity="center"
        android:textColor="#777"
        android:textSize="22sp"
        android:text="3200"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toRightOf="@+id/divider2"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>

    <TextView
        android:id="@+id/label3"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:textColor="#777"
        android:textSize="12sp"
        android:text="Steps"
        app:layout_constraintTop_toBottomOf="@+id/title3"
        app:layout_constraintLeft_toRightOf="@+id/divider2"
        app:layout_constraintRight_toRightOf="parent"/>

</android.support.constraint.ConstraintLayout>

enter image description here


Two buttons one centered one below to the left of it

Showing it graphically.

Centering on parent is done by constraining both sides to the parent. You can the constrain additional objects off of the centered object.

Note. Each arrow represents a "app:layout_constraintXXX_toYYY=" attribute. (6 in the picture)