FlexboxLayout

layout.xml

<?xml version="1.0" encoding="utf-8"?>
<com.google.android.flexbox.FlexboxLayout 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"
    app:flexWrap="wrap"
    android:layout_gravity="center"
    app:alignItems="center"
    tools:context="com.androidfung.layoutsample.MainActivity">


    <android.support.v7.widget.CardView

        android:layout_width="320dp"
        android:layout_height="wrap_content"
        android:layout_margin="8dp"
        android:minWidth="320dp"
        app:layout_flexGrow="1"
        app:layout_gravity="center"
        >

        <TextView
            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" />
    </android.support.v7.widget.CardView>
    <android.support.v7.widget.CardView

        android:layout_width="320dp"
        android:layout_height="wrap_content"
        android:layout_margin="8dp"
        android:minWidth="320dp"
        app:layout_flexGrow="1"
        app:layout_gravity="center"
        >

        <TextView
            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" />
    </android.support.v7.widget.CardView>    <android.support.v7.widget.CardView

    android:layout_width="320dp"
    android:layout_height="wrap_content"
    android:layout_margin="8dp"
    android:minWidth="320dp"
    app:layout_flexGrow="1"
    app:layout_gravity="center"
    >

    <TextView
        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" />
</android.support.v7.widget.CardView>

</com.google.android.flexbox.FlexboxLayout>