activity_login.xml

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginLeft="16dp"
    android:layout_marginRight="16dp"
    tools:context="com.sendbird.androidchattutorial.LoginActivity">

    <android.support.design.widget.TextInputLayout
        android:id="@+id/text_input_login_user_id"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:hint="User ID"
        app:layout_constraintVertical_chainStyle="packed"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toTopOf="@+id/text_input_login_user_nickname"
        android:layout_marginBottom="16dp">

        <android.support.design.widget.TextInputEditText
            android:id="@+id/edit_text_login_user_id"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:imeOptions="actionNext"/>

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

    <android.support.design.widget.TextInputLayout
        android:id="@id/text_input_login_user_nickname"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toBottomOf="@id/text_input_login_user_id"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toTopOf="@+id/button_login"
        android:hint="User Nickname"
        android:layout_marginBottom="16dp">

        <android.support.design.widget.TextInputEditText
            android:id="@+id/edit_text_login_user_nickname"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:imeOptions="actionDone"/>

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

    <Button
        android:id="@id/button_login"
        android:text="Log in"
        android:layout_width="0dp"
        android:layout_height="56dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/text_input_login_user_nickname"
        app:layout_constraintVertical_chainStyle="packed"/>

</android.support.constraint.ConstraintLayout>