Create an empty activity named LoginActivity.kt, and a layout named activity_login.xml. Here is the code in the xml (you will find the full version of this layout on GitHub):

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<android.support.v7.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentStart="true"
        android:layout_centerHorizontal="true"
        android:background="@color/reg_body"
        app:layout_constraintTop_toTopOf="parent" app:layout_constraintStart_toStartOf="parent"
        android:layout_marginBottom="64dp" app:layout_constraintBottom_toBottomOf="parent"
        android:layout_marginStart="32dp" app:layout_constraintEnd_toEndOf="parent" android:layout_marginEnd="32dp"
        android:id="@+id/cardView">


    <android.support.constraint.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintVertical_bias="1.0" android:layout_marginEnd="24dp"
            android:layout_marginTop="32dp"
            android:layout_marginStart="24dp" android:layout_marginBottom="32dp">
        <TextView
                android:id="@+id/LogIn"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentTop="true"
                android:layout_centerHorizontal="true"
                android:text="@string/title_login"
                android:textSize="30sp"
                android:textStyle="bold"
                android:typeface="monospace" app:layout_constraintEnd_toEndOf="parent"
                android:layout_marginEnd="8dp" app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" android:layout_marginStart="8dp"
                android:layout_marginTop="8dp"/>
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 <Button android:layout_width="match_parent" android:layout_height="wrap_content"
                    android:text="@string/title_login"
                    android:id="@+id/reg_submit"

                    app:layout_constraintTop_toBottomOf="@+id/password_title_reg"
                    app:layout_constraintStart_toStartOf="parent" app:layout_constraintEnd_toEndOf="parent"
                    android:layout_marginEnd="32dp" android:layout_marginStart="32dp"
                    android:layout_marginTop="64dp"/>
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Here we have user input for Username and Password. In this layout, we have also one button to log in and one TextView to go to the RegistrationActivity.

Here is the image preview of this layout: